TOP END REFINISHING

[mike100]

I'm lost. Again.

If a vacuum solenoid - EGR, ZR1 secondaries, etc., is in the vent position, ...

http://www.zr1.net/forum/images/icons/icon5.gif

then it vents the actuator diaphragms to the atmosphere speeding up their closing. You should be able to vacuum charge the little black can reservoir at that point. You may have to apply 12v to get the vacuum to pass to the secondaries- I'm away from my FSM's at the moment, but that is the testing path i would take.

[Paul Workman]

Of course, there is another solution -

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/ZR-1009.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/ZR-1009.jpg.html)

Parts that don't exist never break...and they don't cost much! (read: chuck the secondary port throttles - same approach Lotus took on the LT5-II prototype).

Just sayin...:thumbsup:

[Schrade]

Of course, there is another solution -

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/ZR-1009.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/ZR-1009.jpg.html)

Parts that don't exist never break...and they don't cost much! (read: chuck the secondary port throttles - same approach Lotus took on the LT5-II prototype).

Just sayin...:thumbsup:

Would I have to pull the IH's to remove the sec vac system? Is it reversible? Hasn't someone mentioned 'fixing' the secondary Valves OPEN? THAT I have thought of here...

Where the link here Cliff?

[XfireZ51]

Would I have to pull the IH's to remove the sec vac system? Is it reversible? Hasn't someone mentioned 'fixing' the secondary Valves OPEN? THAT I have thought of here...

Where the link here Cliff?

I just tie-wrapped mine open. Later on I took the throttle plates out and left the shafts in. Need to modify the cal so the ECM thinks the secondaries are OK and won't throw a code. I ran like that until I put on ported heads and cam. With just top end done, it pulled 400 at the wheels w headers.

[Paul Workman]

Completely reversible if you tie them open. Just the cost of gaskets and the chip and the tune. I doubt you would ever switch back!

[Schrade]

Is there a vac schematic that shows where to cap off vac lines? To retain Cruise and EVAP functions?

How do you know that the tied sec linkage is holding the sec ports' butterflies perfectly vertical? Or are they vertical when 'pegged'?

[Dynomite]

Would I have to pull the IH's to remove the sec vac system? Is it reversible? Hasn't someone mentioned 'fixing' the secondary Valves OPEN? THAT I have thought of here...

Where the link here Cliff?

LT5 Eliminated Systems (http://forums.corvetteforum.com/c4-zr-1-discussion/2942569-tech-info-lt5-eliminated-systems.html)

I retained the secondary system on my 90' and eliminated secondary on 91' :p

I just wanted to experience the power key on my 90' and not have anyone accuse me of not being able to get a secondary system functioning :D

What you should do is eliminate TB coolant....naw.....I promised GC I would not mention that...so forget I said that ;)

Is there a vac schematic that shows where to cap off vac lines? To retain Cruise and EVAP functions?
There is not a schematic in this link but everything is described in detail LT5 Eliminated Systems (http://forums.corvetteforum.com/c4-zr-1-discussion/2942569-tech-info-lt5-eliminated-systems.html)

You can tie wrap or remove secondary plates or remove shafts completely. With your mechanical talents, anything and everything is reversible :thumbsup:

[Dynomite]

That's this one - correct?



Why can't it be removed as well, with a cap on the plenum port?

Looks like Paul W has it out???



Allen Head Aluminum Plug like this where it says Plenum Vacuum ;)

http://i287.photobucket.com/albums/ll142/dynomite007/LT5/PlenumblockN.jpg

[XfireZ51]

That's this one - correct?

https://lh6.googleusercontent.com/-X9sv7wR_teU/UokJMKTwHfI/AAAAAAAAC3Y/CrW7uRpXDp4/s1280/HPIM7543.JPG

Why can't it be removed as well, with a cap on the plenum port?

Looks like Paul W has it out???

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/ZR-1009.jpg


Because you'll want to use it when u install the DynoMax Ultraflos
w the Z06 NPP tips/actuators. ;)

[Paul Workman]

All the HVAC, cruise, etc gets it's vacuum from the starboard-side plenum nipple between #4 and # 6.

On mine I left the port side vacuum connector (the one that serves the SPTs) and a short piece of the hose tucked under the plenum. But, the hose is plugged, giving it an "un-altered" appearance. Same goes for the TB bypass. The IH is plugged, but I left the hoses "as tho" everything were stock. (That way Scottfab wouldn't have a cow if ever he saw a photo of my motor (:mrgreen:) (Oh, I like Scott a lot. But, he definitely sees thing trough a different prism than I do...make that MOST do!:p LOL!)

Hats off to you. You may not have all the answers (most of us don't), but you haven't let that deter you from forging ahead anyway. Serendipity is one hell of a teacher!! In the end, you'll know more about the top end (at least) than more than half of the ZR-1 drivers do, I'd bet! Good on you!!=D>

[XfireZ51]

I left the actuators on and used tie wraps. Worked just fine for months.

[Paul Workman]

Uhhhhh.... Well... I don't know that I'd ever brush a gasket with a wire brush before reinstalling it; wiping it clean with brake cleaner on a rag, tho perhaps.

I DO spray one side of the gasket (the top side) with silicon spray as a release agent to facilitate future removals w/o damaging the gasket. I don't know that I'd use grease, but for sure you want the gasket to stay put, i.e., not squirm around, especially near coolant passages.

I've experience a few gaskets that slid around, e.g., this one was actually the IH/head gasket. Note the gasket has squeezed into the runner, and the coolant too. (This can be a problem with ported runners especially, as the space between coolant and the runner gets narrow.)

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/ZR-1007.jpg (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/ZR-1007.jpg.html)

This happened within weeks of installation on a couple occasions (note the runners are significantly ported). I had been smearing a film of RTV on the gaskets - thinking that would "help". NOT!

I switched to Jerry's gaskets, and it was he (as I recall, Jerry?) that suggested than the gaskets be applied dry (read: NO RTV, etc to "help").

Now (especially with ported top end) I take great pains to get the metal surfaces absolutely dry and clean with (CRC - red can) brake cleaner and a razor blade, before installing (Jerry's gaskets) dry, except on the IH around the coolant port. There, around the coolant port only, I use some Permatex sealer (I forget the exact part number, but it is opaque, powder blue colored, bonds like glue and seals as well). That seems to have done the trick!

Well, you may get away with it (greasing the gasket(s)). But, if you develop a high idle later, you'll have a pretty good idea where to start looking.

Don't forget the BLUE LOCTITE on the threads before torquing the plenum/IH.

[Dynomite]

Don't forget the BLUE LOCTITE on the threads before torquing the plenum/IH.

Concur :thumbsup:

Clean, dry bolts with a couple drops of blue Loctite on bottom threads of bolts (Injector Housing) and thin coat of Permatex on gaskets (except when I have a gasket NOT exposed to coolant in which case NOTHING on gasket). Red Loctite on everything inside the Front Cover. Blue Loctite on Oil Pan Bolts. Nothing on Head Gasket and nothing on Plenum gasket since I have TB/Plenum coolant locked.

Actually I do not use any Loctite on my SS Allen Head Bolts (Cam Covers or Plenum). I use Aluminum Stat-O-Seal Washers on all Allen Head SS Steel Bolts installed in the Plenum and Cam Covers (including the IH Coolant Manifolds).

Aluminum Stat-O-Seal washers with molded Buna-N inner seals are much more reliable than the more common steel stat-o-seals. If the rubber portion fails to make contact all around the port, the aluminum will act as a crush washer, providing a reliable metal to metal seal. Use them to seal screws, bolts or plumbing fittings. The Buna-N seal is resistant to petroleum fuels and oils.

http://i287.photobucket.com/albums/ll142/dynomite007/ZR1%20NET/StatOSeal.jpg

[XfireZ51]

Why not just get a cover from Lgaff?

[Schrade]

Memory / Calibration Module to Marc... (and maybe it WILL get there quicker ;) )

https://lh3.googleusercontent.com/-rsAgrC5joDg/UopywoY2XnI/AAAAAAAAC7E/t0jybK4bLJw/s1280/Untitled.jpg

[Schrade]

Any tricks to getting on a new UN-stretched serpentine belt? This Dayco is a bear here...

[Dynomite]

Any tricks to getting on a new UN-stretched serpentine belt? This Dayco is a bear here...

Make sure you have the correct length belt :p

Then....having someone hold the tensioner open.....slip belt under water pump pulley (the back side of the belt) onto the smooth surface of the water pump pulley.

Actually I have an aluminum Water Pump pulley with NO lip. For your stock situation maybe the alternator is the final pulley.

[Schrade]

Make sure you have the correct length belt :p

Then....having someone hold the tensioner open.....slip belt under water pump pulley (the back side of the belt) onto the smooth surface of the water pump pulley.

Actually I have an aluminum Water Pump pulley with NO lip. For your stock situation maybe the alternator is the final pulley.

Hmm... might NOT be the right belt here Cliff - sure is CLOSE fit tho'...

What IS spec length?

Advance's database has some L98 parts indexed as LT5...

ed.:
Dayco web info shows correct

This product is a fit for your:
1990 Chevrolet Corvette ZR-1 5.7L MFI DOHC 8cyl
Part Number: 5060805
Warranty: 3 YR (http://www.autozone.com/autozone/termsandconditions/termsAndConditionsHome.jsp?leftNavPage=warranties&pageCategory=warranties)

[Dynomite]

Hmm... might NOT be the right belt here Cliff - sure is CLOSE fit tho'...

What IS spec length?



That I am not sure on the length.......as I have several different lengths having installed different alternator, Power steering, and Water Pump pulleys from time to time. You should be able to get the belt started around the alternator pulley....it might be tight but slip it over one groove at a time.

[Bearly Flying]

Schrade; With all the work you have done to date, why not get your intake ported, You have already eliminated the secondaries, Give Lgaff a shout and get your plenum ported, He does Great work....

In for a penny.... in for a Pound....

[A26B]

Not burned away.

Autolite® XP Xtreme Performance® Spark Plugs

•Iridium-enhanced center electrode
•Patented, platinum sidewire technology.
•.6-mm finewire design
•Nickel-plated shell

[Franke]

Schrade, what is the gap on those plugs? Should be .035. I don't use Autolite plugs I stay with AC Delco for the Z.
I think the HVAC line goes into the firewall with the harness for the vac operated hvac doors, controls etc. Not sure you can access it at the firewall. Maybe someone else knows for sure.
Vacuum leaks generally show up at idle which I remember was not an issue from your datamaster video.

[mike100]

Yellow circled item is the air injection diverter valve. it is connected properly from the looks of it. The big outlet with no hose is a purge to the atmosphere. the other hose goes to the air injection lines.

[Schrade]

Thanks there Mike - like I've said before, I don't know much... Vacuum does hold at the device, which I'm guessing is correct...

Cruise solenoid :rolleyes: - don't laugh too loud

Anyone remember the name of the CF user who's the A/C guru? 'Sun-tech', something or other... (can't log on since being banned) - he is THE A/C expert, and need to know if the vacuum line that goes to the HVAC should hold vacuum when system is powered down.

ed.:
Got it; the CF user is suncr. Dom; Darryl - know if he happens to be registered here? Know him on CF boards there???

[Dynomite]

Coolant cross-over in place, plus new serp belt...



Looking great :thumbsup:

Are those new coolant hoses?
Those hose clamps look PLENTY tight ;)

I have to check my 90'.....I do not recall those two wire clamps attached to my AC compressor (what wires are they?) :dontknow:

But then again...I reroute vacuum lines and wires somewhat differently than stock when I rebuild an LT5. For example, the wire bundle going forward on driver side goes OVER upper drivers side A-Arm. I loosen the A-Arm and slip that wire bundle UNDER the A-Arm out of the way.

Are you checking fuel pressure (Schrader valve on passenger side fuel rail)?

[Franke]

Looking great :thumbsup:

Are those new coolant hoses?
Those hose clamps look PLENTY tight ;)

I have to check my 90'.....I do not recall those two wire clamps attached to my AC compressor (what wires are they?) :dontknow:

But then again...I reroute vacuum lines and wires somewhat differently than stock when I rebuild an LT5. For example, the wire bundle going forward on driver side goes OVER upper drivers side A-Arm. I loosen the A-Arm and slip that wire bundle UNDER the A-Arm out of the way.

Are you checking fuel pressure (Schrader valve on passenger side fuel rail)?

Wiring could be compressor clutch?:dontknow:

[Schrade]

Looking great :thumbsup:

Are those new coolant hoses?
Those hose clamps look PLENTY tight ;)

I have to check my 90'.....I do not recall those two wire clamps attached to my AC compressor (what wires are they?) :dontknow:

But then again...I reroute vacuum lines and wires somewhat differently than stock when I rebuild an LT5. For example, the wire bundle going forward on driver side goes OVER upper drivers side A-Arm. I loosen the A-Arm and slip that wire bundle UNDER the A-Arm out of the way.

Are you checking fuel pressure (Schrader valve on passenger side fuel rail)?

Thanks there Cliff...

Coolant hoses are the ones that were on there. You think the clamps are a little too tight? I snug 'em just til the clamp is at the level of the rubber, in a different spot, of course...

The 2 wires on the A/C comp I think are the A/C clutch engage wires.
https://lh5.googleusercontent.com/-5_LGuG1CO_0/UogqXy0R5JI/AAAAAAAAC1w/mx8WNuSLVKM/s1280/HPIM7538.JPG
In Paul Workman's photo, I can't see them there either... :confused: maybe just out of the frame.

Unless you're talking about the 2 vac lines in the Blue bread bag tie? Not too sharp work - I know.

FP guage is still plugged in - I haven't gotten a good leakdown yet - think it still has air in the line. It held good first time, before I broke it down to find the missing socket. And cut the other O-ring in the process :censored:

Still gotta' check the vacuum to HVAC hose (hate to go into the dash for that, unless I can find out what circuit to jump, such that it's supposed to hold, THEN check), CC-to-PCV cross-over back in (withOUT dropping the socket), SP boots + wipedown, bolt the TB 2' butterflies into the shaft (thanks again for the screws BF), coolant, and the chip from MarcH for the 2' delete, plenum, ... Maybe another 2 weeks??? UGH..........................

[Dynomite]

The 2 wires on the A/C comp I think are the A/C clutch engage wires.

Coolant hoses are the ones that were on there. You think the clamps are a little too tight? I snug 'em just til the clamp is at the level of the rubber, in a different spot, of course...


:handshak:
Yep....on my 90' those two wire clips were missing and I routed the wire down under the AC pipes.....because I did not know any better :D

On my 91' I DO have those two clips.....Oh...well ;)

I guess I would have installed NEW coolant hoses (Marc has the coolant hoses as well as Jerry now has the Silicon Hoses and appropriate hose clamps)

Marc Haibeck Coolant Hoses (http://www.zr1specialist.com/HAT%20Web/products/hoses.htm)

Jerry's Silicon Coolant Hoses (http://jerrysgaskets.com/store2/root/index.php?main_page=advanced_search_result&search_in_description=1&keyword=silicon+hose)

Jerry's Silicon Coolant Hose Clamps (http://jerrysgaskets.com/store2/root/index.php?main_page=product_info&cPath=5&products_id=826)

[Schrade]

Thanks there Cliff...

Coolant hoses are the ones that were on there. You think the clamps are a little too tight? I snug 'em just til the clamp is at the level of the rubber, in a different spot, of course...

The 2 wires on the A/C comp I think are the A/C clutch engage wires.
https://lh5.googleusercontent.com/-5_LGuG1CO_0/UogqXy0R5JI/AAAAAAAAC1w/mx8WNuSLVKM/s1280/HPIM7538.JPG
In Paul Workman's photo, I can't see them there either... :confused: maybe just out of the frame.

Unless you're talking about the 2 vac lines in the Blue bread bag tie? Not too sharp work - I know.

FP guage is still plugged in - I haven't gotten a good leakdown yet - think it still has air in the line. It held good first time, before I broke it down to find the missing socket. And cut the other O-ring in the process :censored:

Still gotta' check the vacuum to HVAC hose (hate to go into the dash for that, unless I can find out what circuit to jump, such that it's supposed to hold, THEN check), CC-to-PCV cross-over back in (withOUT dropping the socket), SP boots + wipedown, bolt the TB 2' butterflies into the shaft (thanks again for the screws BF), coolant, and the chip from MarcH for the 2' delete, plenum, ... Maybe another 2 weeks??? UGH..........................

2 weeks for me screwing something up; NOT ON MARC'S ACCOUNT - did NOT mean that Marc!!!

[Franke]

Schrade, Reading in the FSM indicates the black hose from the vacuum tank (left front fender) goes to the heater/AC control head in the dash (black hose) and is where vacuum is distributed to the various duct doors. Pages 8a-68-5. It doesn't look like there is any way to check in between those two points for vac leaks.

[Franke]

Maybe that hesitation might go away with the eprom recal.

[Schrade]

Ok - just read the coolant bypass thread (http://www.zr1.net/forum/showthread.php?t=11425) in entirety...

Jury still out?

My lines are painted, so bypass or not, the lines will stay.

Fuel line ok for a by pass?

[Dynomite]

Great Photos and a very colorful LT5 for sure :thumbsup:

I am not sure why you did not just block off TB coolant with a 1/8 inch Allen Head Pipe plug (same with IH housing and Plenum TB coolant path). That would eliminate having to draw down coolant every time you remove the Plenum which I just know will be whenever you get the urge :D

I defined a great Coolant Filling technique which has eliminated the fear of Water Pump Air Locking after a Coolant Refill.

Are you uncertain of TB Icing? Just am interested in your opinion leading to your modifications.

Thanks,
Cliff

[Schrade]

Great Photos and a very colorful LT5 for sure :thumbsup:

I am not sure why you did not just block off TB coolant with a 1/8 inch Allen Head Pipe plug (same with IH housing and Plenum TB coolant path). That would eliminate having to draw down coolant every time you remove the Plenum which I just know will be whenever you get the urge :D

I defined a great Coolant Filling technique which has eliminated the fear of Water Pump Air Locking after a Coolant Refill.

Are you uncertain of TB Icing? Just am interested in your opinion leading to your modifications.

Thanks,
Cliff

What's up Cliff...

If [when] I pull the plenum again, I don't relish the idea of coolant getting all over cleaned parts. Mike100 said it gets dirty under there, but I do more cleaning / tuning, than driving (they called my '94 a 'garage queen' on CF before banning. Not QUITE so...).

anyway

Marc's page says 20' w/ 90% RH, can cause ice-up, and we DO get that here on RARE occasion. But I think even ONLY with sustained hammer down, under those conditions, will you get ice. And I got an extra 'radiator' up front, for the automatic, and the fans stay on most of the time, with the extra heat.

And thanks to Marc for gettin' the re-coded Memory / Calibration module back in short order here http://www.zr1.net/forum/images/icons/icon14.gif (I sure wish someone ELSE could get somethin' in the mail to me as fast as he did, for my tranny http://www.zr1.net/forum/images/icons/icon13.gif ).

Where's the info on bleeding air from coolant lines? Doesn't the air push through after a couple of Closed Loop outings?

[Schrade]

And as far as the TB coolant ports, they are kind of ugly as they are (the caps on now are just temporary).

Only thing I can think of to reduce their 'profile', is spot 'em with the Satin Black.

You got a snappic of the 1/8 inch Allen Head Pipe plugs, that you have installed?

What did the rest of you do? I'd like to keep it 're-configure-able', to OEM, just in case...

[Dynomite]

Where's the info on bleeding air from coolant lines? Doesn't the air push through after a couple of Closed Loop outings?

Getting The Air Out of the Coolant System (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1580070565)

See Details here of how to get the Air Out of the Air Locked Water Pump Filling With Coolant and the Air Locked Water Pump (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-5.html#post1581827089)

You got a snappic of the 1/8 inch Allen Head Pipe plugs, that you have installed?


See Item #4 LT5 Eliminated Systems (http://forums.corvetteforum.com/c4-zr-1-discussion/2942569-tech-info-lt5-eliminated-systems.html) You can get the 1/8 inch Allen Head Pipe Plugs at Summit Racing as referenced in the LT5 Eliminated Systems post ;)

There is also a 1/8 inch Allen Head Pipe Plug inserted in the top of each Injector Housing that makes sure you do not have coolant issues when removing the Plenum. That is the Pipe Plug that actually stops the coolant flow. The other (two each side) only plug the holes in the Plenum and TB.

http://i287.photobucket.com/albums/ll142/dynomite007/LT5/PlenumblockN.jpg

[Schrade]

She spun right up, second try, DESPITE:

I forgot to plug in the TPS.
Forgot to CALIBRATE the TPS.
Had the A/C head unit un-plugged.
Forgot to plug in the rear vacuum connector of the 2 at the plenum, behind the TB.
AND the vacuum connector under the TB extension!!!

I know there's air in it still - it went to about 245 pretty quick - I didn't fill with one of the coolant manifold elbows turned up...

And she's idling at about 1,250.

Anyway, still lots to do, and she'll have to wait til after Thanksgiving.

YouTube (uploading now):

http://www.youtube.com/watch?v=OqjZd_GOaWg&feature=youtu.be

or here

https://www.youtube.com/watch?v=OqjZd_GOaWg

[Dynomite]

I know there's air in it still - it went to about 245 pretty quick - I didn't fill with one of the coolant manifold elbows turned up...



Getting the Air Out of the Coolant System

The two coolant manifolds attached to the injector housings should get warm within 30 seconds with engine running if the water pump is pumping coolant. If not......you have to get that air out of the water pump area (Air Locked Water Pump). See LT5 Air Locked Water Pump Simplified (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584756847)



See LT5 Radiator and Initial Coolant Fill Tricks (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1580070559)

[Franke]

Yeah what Dyno says but don't drink the coolant:) Motor looks good and it seemed to run/sound good albeit the high idle etc. Are you going to run Datamaster again?

[Schrade]

Yeah - I'll plug in DataMaster as soon as I re-calibrate TPS.

No SES for high idle tho', and it DID come on right away FIRST time (idled @ 3k then), when TPS was unplugged. After shut-off, battery dis-connect, and plugging in TPS, it dropped to 1,250. I think it's the last vacuum connector UNDER TB extension - can't remember where that one went...

[5ABI VT]

Schrade Awesome thread especially with all the pics. I wish I could contribute but I haven't pulled my plenum off yet. I plan to and Ill be eliminating the coolant in the plenum and tb as well as the secondaries when I do mine. Your pics and all the little steps you've gone through are a huge help :) =D>

[Schrade]

Schrade Awesome thread especially with all the pics. I wish I could contribute but I haven't pulled my plenum off yet. I plan to and Ill be eliminating the coolant in the plenum and tb as well as the secondaries when I do mine. Your pics and all the little steps you've gone through are a huge help :) =D>

Thank you Sir! The thread hits were plenty encouraging, so you helped I'm sure. And
if I can get it done, anyone can (of course, it ain't done yet [NEVER is], but nothing got broken, and no 'problems')...

I could not get the 90' plenum fitting tight in the correct position, for the TB / coolant by-pass. The fabbed by-pass line is still in place, not obstructing anything (see in the video), so I won't have to yank the top to re-reroute it at a later date.

I tried Teflon tape on the fitting threads, and then thread sealant, without the tape, but didn't feel comfy with that. So for now, it's still running through the TB.

First post edited for Cliff's links info...
DEFINITELY read Cliff's links when he posts them. They're not always directly to the pertinent information - you'll have to read it ALL to get to the info, but it's ALL there, and you HAVE to go through it. (Thanks a ton for that stuff Cliff). Use your bookmarks tool in your browser for it, and note that sometimes you'll run across info that's IMPORTANT at a later point...

[Z06scentair]

Is it running yet? If so how well?

[Schrade]

Is it running yet? If so how well?

https://www.youtube.com/watch?v=OqjZd_GOaWg

[Z06scentair]

https://www.youtube.com/watch?v=OqjZd_GOaWg

Sounds good have you had it on the street yet? Curious how the auto will do in the car?

[XfireZ51]

What's it idling at?

[Schrade]

What's it idling at?

Still idling at 1k, with TPS calibrated.

And, it's not steady - about a 75 RPM swing, so I can't tell if it's a vacuum leak lope, or what...

To boot, I don't know about the hesitation gig.

New DataMaster uploading now; called Jon B / FIC, for new injectors, which I think are indicated by the DM vid...

[XfireZ51]

Still idling at 1k, with TPS calibrated.

And, it's not steady - about a 75 RPM swing, so I can't tell if it's a vacuum leak lope, or what...

To boot, I don't know about the hesitation gig.

New DataMaster uploading now; called Jon B / FIC, for new injectors, which I think are indicated by the DM vid...

Have you set the Min Air adjustment? When you get DM connected, what is IAC doing at "idle"? How many IAC counts? What does "TPS calibrated"mean? What is the coolant temp as it's idling? Why do you think you need new injectors?

[mike100]

All you need to do is make sure your TPS is set to the indicated voltage at zero percent opening (about .54v if i recall). The IAC counts are probably 0 if it can't make it run slower than 1k rpm.

you either had a line pop off during reinstallation (or a mistake in tube routing), or your throttle body blade redo got messed up a little. Just seems like too much air. maybe you should double check the throttle angle and not the electrics.

[Schrade]

Have you set the Min Air adjustment? When you get DM connected, what is IAC doing at "idle"? How many IAC counts? What does "TPS calibrated"mean? What is the coolant temp as it's idling? Why do you think you need new injectors?

Minimum air adjustment? You mean the throttle stop screw? Haven't played with that just yet...

TPS calibration - set TPS at .54V with adjustment screws.

[XfireZ51]

All you need to do is make sure your TPS is set to the indicated voltage at zero percent opening (about .54v if i recall). The IAC counts are probably 0 if it can't make it run slower than 1k rpm.

you either had a line pop off during reinstallation (or a mistake in tube routing), or your throttle body blade redo got messed up a little. Just seems like too much air. maybe you should double check the throttle angle and not the electrics.

Mike,

Yes I know about setting the TPS v, but that is affected by the Min Air adjustment. You need to get the throttle blade opening correct before you can set the idle TPS voltage properly. It's an iterative process.
Turn the key ON, then pull the IAC CONNECTOR. This should block the IAC port to the throttle body. Then start the motor. Does it idle, and if so at what RPM?
If it's too high, you need to close the throttle blades till you reach the desired idle speed. You actually set it a bit lower so you get some IAC control over the idle. Whenever you adjust the throttle blade, need to re-check TPS voltage and adjust if necessary so it is below the idle voltage threshold. Otherwise, ECM won't use the correct Spark Timing and you end up w an idle hunt.

[Schrade]

Mike,

Yes I know about setting the TPS v, but that is affected by the Min Air adjustment. You need to get the throttle blade opening correct before you can set the idle TPS voltage properly. It's an iterative process.
Turn the key ON, then pull the IAC CONNECTOR. This should block the IAC port to the throttle body. Then start the motor. Does it idle, and if so at what RPM?
If it's too high, you need to close the throttle blades till you reach the desired idle speed. You actually set it a bit lower so you get some IAC control over the idle. Whenever you adjust the throttle blade, need to re-check TPS voltage and adjust if necessary so it is below the idle voltage threshold. Otherwise, ECM won't use the correct Spark Timing and you end up w an idle hunt.

Got it there Dominic; will start there in the AM. I was tentative about playing with that, to be able to reverse any adjustment.

Y/T - best I could do this time... I need to change DM window font...
http://www.youtube.com/watch?v=J_9VApesl_o


Sounds good have you had it on the street yet? Curious how the auto will do in the car?
Auto runs fine Z06, although I can by no means rule out EMI interefence in this hesitation diagnostic issue. SOME circuit 'sings', in sync with TPS range of motion - best I can describe THAT. I can catch that in a vid too, but if anyone can make anything of it, I'll be HAPPILY surprised...


All you need to do is make sure your TPS is set to the indicated voltage at zero percent opening (about .54v if i recall). The IAC counts are probably 0 if it can't make it run slower than 1k rpm.

you either had a line pop off during reinstallation (or a mistake in tube routing), or your throttle body blade redo got messed up a little. Just seems like too much air. maybe you should double check the throttle angle and not the electrics.
Understood Mike; DM does indicate 0% TB opening, but again, Min Idle adjustment might come before TO % confirmation.

[mike100]

If you didn't break the adjustment on the throttle stop, that's probably not your issue. I would do what you have to to read the IAC count value on your data stream. (or pull the IAC plug as suggested above).

Lets not make it complicated beyond that. There seems to be a fundamental air leak. it is often suggested to take a stiff binder book cover or similar and block off the air horn (accordion duct removed) while the engine is idling to try to stall it. if it still runs, you can often hear the point of the air leak under the plenum.

[efnfast]

Schrade, did you clean the slimy stuff out of the throttle body,around the plates, nice and clean now?

[XfireZ51]

R U saying you did re-install the throttle blades? The stock throttle stop stud uses an Allen wrench for adjusting. As Mike pointed out, GM didn't mean for this to be adjusted, but hey this is 20+ years later and things wear and go out of adjustment. These motors are being modified including the throttle body. The point is to check that all the basic mechanical components are working properly before chasing a vacuum leak. It's A PITA which is why several of us have replaced it w an 8mm hex head bolt. One thing to do is take a .002" feeler gauge and see if it drags w the throttle blades closed. A strip of paper will work also. It's a close approximation of where the blades should be with a stock motor. Make sure the motor is up to operating temps before you check on IAC counts and/ or decide to adjust the Min Air.

[Paul Workman]

Mike,

Yes I know about setting the TPS v, but that is affected by the Min Air adjustment. You need to get the throttle blade opening correct before you can set the idle TPS voltage properly. It's an iterative process.
Turn the key ON, then pull the IAC CONNECTOR. This should block the IAC port to the throttle body. Then start the motor. Does it idle, and if so at what RPM?
If it's too high, you need to close the throttle blades till you reach the desired idle speed. You actually set it a bit lower so you get some IAC control over the idle. Whenever you adjust the throttle blade, need to re-check TPS voltage and adjust if necessary so it is below the idle voltage threshold. Otherwise, ECM won't use the correct Spark Timing and you end up w an idle hunt.

Hi Dom,

Touched on something there...as I have idle hunting when the engine is real cold; at/near freezing or below. It goes away as the motor temp gets over around 60º - there abouts.

...and adjust if necessary so it is below the idle voltage threshold.

I'm with you until the term idle voltage threshold. I'm not sure exactly what you're referring to. Do you mean the TPS at idle; a la the 0.54V?? Not sure where I got confused...

[XfireZ51]

Hi Dom,

Touched on something there...as I have idle hunting when the engine is real cold; at/near freezing or below. It goes away as the motor temp gets over around 60º - there abouts.

...and adjust if necessary so it is below the idle voltage threshold.

I'm with you until the term idle voltage threshold. I'm not sure exactly what you're referring to. Do you mean the TPS at idle; a la the 0.54V?? Not sure where I got confused...

Paul,

Most likely the motor is surging when cold because the Open Loop AFR may be too lean as the motor warms up. On modified motors, the warm up routine may need a higher rpm setting also. The IAC wants to close as CTS increases but it will open up to prevent stalling. So you end up w a seesaw effect. Then it will go into Closed Loop and stabilize. A while back, I posted a vid of my car going through the warm-up routine. If done right, the motor should go into C/L without much discernible difference than O/L.
As for the TPS, the calibration uses a value of >1% for TPS Position to indicate that the motor is no longer at idle. Mine is set at 1.17%. When you adjust the throttle stop, it changes the % TPS as a consequence. So as you make the Min Air adjustment, it's important to check that the TPS V is at or below the voltage the ECM considers to be idle. The calibration has an Idle Spark Advance that overrides the SA in the tables. That's so you get a consistent SA and it doesn't change as the MAP fluctuates. Especially an issue w cammed motors. On any motor, if the TPS V is above the idle setting, the ECM will use the SA in the tables and you could get a hunting idle which may be interpreted as a vacuum leak. Make sense?

[Schrade]

Have you set the Min Air adjustment? When you get DM connected, what is IAC doing at "idle"? How many IAC counts? What does "TPS calibrated"mean? What is the coolant temp as it's idling? Why do you think you need new injectors?

Cold motor; idling STEADY @ 900.

DM IAC says 150.

[Schrade]

Do I pull the IAC BEFORE, or AFTER adjusting Min Idle stop screw?

[Schrade]

If you didn't break the adjustment on the throttle stop, that's probably not your issue. I would do what you have to to read the IAC count value on your data stream. (or pull the IAC plug as suggested above).

Lets not make it complicated beyond that. There seems to be a fundamental air leak. it is often suggested to take a stiff binder book cover or similar and block off the air horn (accordion duct removed) while the engine is idling to try to stall it. if it still runs, you can often hear the point of the air leak under the plenum.

The linkage bracket cage, bolted to the side of the throttle body, COULD be bolted back on to the TB, such that it's in a slightly different position, which COULD necessitate the Min Idle adjustment.

[Schrade]

Key ON, pulled IAC, cranked it, and it went to 3k rpm.

[Schrade]

Schrade, did you clean the slimy stuff out of the throttle body,around the plates, nice and clean now?

Throttle bores are spotless. Butterflies let no light through when the TB was re-assembled.

[efnfast]

Throttle bores are spotless. Butterflies let no light through when the TB was re-assembled.

??? Guys? I'm no expert, but they told me not to clean the DAG out of there?

[A26B]

Key ON, pulled IAC, cranked it, and it went to 3k rpm.
Don't pull the IAC valve, only the electrical connector to the IAC valve. With the IAC valve removed, you have opened a large bypass around the throttle body.

[Schrade]

??? Guys? I'm no expert, but they told me not to clean the DAG out of there?

The shiny sealing film is intact - I saw that posted many pages ago.

(I had a feeling that's what you were getting at there Steve ;) )


Don't pull the IAC valve, only the electrical connector to the IAC valve. With the IAC valve removed, you have opened a large bypass around the throttle body.
I should have said that I pulled the IAC CONNECTOR...

[efnfast]

OK, seems like that would be an easy mistake to make. I thought about rereading the whole thread, figured it must have already been mentioned, but it's a loooong thread.

[Schrade]

OK, seems like that would be an easy mistake to make. I thought about rereading the whole thread, figured it must have already been mentioned, but it's a loooong thread.

I can't afford to not go back - too much good stuff I miss if I don't....

I cannot get an Allen head in that Min Adj stud either... I did get a 5/16" on the nut, and got it backing out ATM.

[Schrade]

Put a phone book over the TB extension - a hiss started, then got LOUD...

[Schrade]

Found it. Right [near] the FPR vacuum connection to the plenum.

(turned out to be the plenum-to-PCV cap connector. It had a zip tie, and I hadn't replaced it)

Can't hear it too well in the vid; I tried to get the hose near the mike in the cam, but when I held the hose to my ear, it almost pulled out my brain cells. All 2 of 'em :mrgreen:

http://www.youtube.com/watch?v=Hw0mfEs8bLk

So now, it's still idling with a 150rpm swing, 775 - 925... An IRREGULAR lope.

[XfireZ51]

Found it. Right [near] the FPR vacuum connection to the plenum.

(turned out to be the plenum-to-PCV cap connector. It had a zip tie, and I hadn't replaced it)

Can't hear it too well in the vid; I tried to get the hose near the mike in the cam, but when I held the hose to my ear, it almost pulled out my brain cells. All 2 of 'em :mrgreen:

http://www.youtube.com/watch?v=Hw0mfEs8bLk

So now, it's still idling with a 150rpm swing, 775 - 925...

Ok. Is IAC disconnected? If not, what does DM tell you for IAC counts and what is TPS V at idle? If it's not .57v > TPS > .53v, then adjust TPS with motor OFF.
START motor, then let it idle down. What happens? Still surging? Also, if you unplugged IAC, you should have done an IAC reset after plugging it back in.

[XfireZ51]

Split BLMs are nothing new for the LT-5 especially at idle. Not a reason to buy new injectors. Were these the originals or replacements? One of the issues I discussed regarding the proper injector offset. As it is, these aren't bad. Can u tell if LEARN is ON?

[Schrade]

Split BLMs are nothing new for the LT-5 especially at idle. Not a reason to buy new injectors. Were these the originals or replacements? One of the issues I discussed regarding the proper injector offset. As it is, these aren't bad. Can u tell if LEARN is ON?

Don't know if this version of DM tells if learn is on or not :dontknow: Anyone?

Can't I assume that it IS on? Since the Short Term is closer to 128, than Long Term?

Doesn't 'Learn' begin a few minutes after CL starts?



No one chimed in to ID the injectors by the snappics, and I SURE don't know.

Anyway here, why did the thing turn @ 3k when I ran it with IAC dis-connected earlier? Could it have been because of the vac leak @ the plenum-PCV connector?

Re-try IAC dis-connect first thing AM...

[Franke]

FWIW...after I replaced my injectors and O2's my Datamaster file CL showed both banks long term trims to be pretty steady at 128/129 L-R. Short term varied slightly about 127-130 for a 15min idle run.
I can tell you that originally I had a bad primary fuel injector (6 ohms hot) (12 ohms cold) on the left bank that gave the same rich indication that you have on your right bank Lterm. I don't know if that helps or muddies the water more.

Without knowing the part number of your injectors its a hard guess if they are original or not but I will tell you my original injectors looked pretty much the same as yours in the pics. I think I mentioned this wayyyyy back in this thread. I would ohm the primaries out cold and hot and write them down.

[XfireZ51]

Don't know if this version of DM tells if learn is on or not :dontknow: Anyone?

Any datalogger should indicate whether LEARN is ON or not

Can't I assume that it IS on? Since the Short Term is closer to 128, than Long Term?

Doesn't 'Learn' begin a few minutes after CL starts?

No. You must be in C/L in order for LEARN to be on, but u can be in C/L and have LEARN OFF.



No one chimed in to ID the injectors by the snappics, and I SURE don't know.

Anyway here, why did the thing turn @ 3k when I ran it with IAC dis-connected earlier? Could it have been because of the vac leak @ the plenum-PCV connector?

Re-try IAC dis-connect first thing AM...

Did u disconnect the IAC OR remove it? If you disconnected it w key ON, then that will block the IAC port. Now if you have remedied the PCV leak, then only one place the air is coming from and that's the throttle blades being too far open. Let's see if it idles and at what rpm?

[Schrade]

Any datalogger should indicate whether LEARN is ON or not

...

No. You must be in C/L in order for LEARN to be on, but u can be in C/L and have LEARN OFF.

...



Did u disconnect the IAC OR remove it? If you disconnected it w key ON, then that will block the IAC port. Now if you have remedied the PCV leak, then only one place the air is coming from and that's the throttle blades being too far open. Let's see if it idles and at what rpm?

I had it electrically dis-connected, AFTER key ON - not removed. And I haven't seen a readout, besides '0', in DM, for IAC yet. ??? No SES lights, including for dis-connected IAC.......................................

Will re-try IAC dis-connect again shortly here. This should be done Closed Loop? Or Open?

[XfireZ51]

I had it electrically dis-connected, AFTER key ON - not removed. And I haven't seen a readout, besides '0', in DM, for IAC yet. ??? No SES lights, including for dis-connected IAC.......................................

Will re-try IAC dis-connect again shortly here. This should be done Closed Loop? Or Open?

There is no MALF code for IAC. I would run the motor till it is warm and indicated C/L. Then shut down. Ignition ON, disconnect IAC. Ignition OFF, then Engine Start. Allow the start-up routine to stabilize timing, then check idle RPM.

[Schrade]

There is no MALF code for IAC. I would run the motor till it is warm and indicated C/L. Then shut down. Ignition ON, disconnect IAC. Ignition OFF, then Engine Start. Allow the start-up routine to stabilize timing, then check idle RPM.

Alright - went this way perfectly; idle stayed 2275 - 3k for 2 minutes.

Next?


ed.:
Ok. Is IAC disconnected? If not, what does DM tell you for IAC counts and what is TPS V at idle? If it's not .57v > TPS > .53v, then adjust TPS with motor OFF.
START motor, then let it idle down. What happens? Still surging? Also, if you unplugged IAC, you should have done an IAC reset after plugging it back in.
TPS voltage .55; IAC 0

[XfireZ51]

Just trying to clarify, with IAC disconnected, warm idle was at 2200rpm? I am looking at 2 different scenarios you just posted. If O/L went smoothly, I would discount an issue w the injectors.
Remove the IAC completely and plug up that port physically making certain that no bypass air is entering. What's your idle at coolant operating temps and C/L?
Is your motor completely stock or what mods have been done

[Schrade]

OK - I think I understand - 'block the port' for by-pass air.

Which of the 2 internal ports is this? The port in the SIDE of the IAC bore? Or in the END of the IAC bore

[Schrade]

The IAC pintle has HEAVY corrosion on it. I know this did not seal.

I hit it only with solvent, and THAT wouldn't touch what I have here...

[XfireZ51]

The IAC pintle has HEAVY corrosion on it. I know this did not seal.

I hit it only with solvent, and THAT wouldn't touch what I have here...

It helps to clean the pintle and the IAC bore where the pintle moves into/out of.
And yes that is the port you block off. The outer port is the bypass air and the IAC controls how much of that air bypasses and controls idle.
So yes clean the pintle and bore. However, I would still block off the IAC port physically and see what happens w the idle.

[Schrade]

It helps to clean the pintle and the IAC bore where the pintle moves into/out of.
And yes that is the port you block off. The outer port is the bypass air and the IAC controls how much of that air bypasses and controls idle.
So yes clean the pintle and bore. However, I would still block off the IAC port physically and see what happens w the idle.

Cleaned pintle, and re-checked CL idle. Still high - 775 - 900, SLIGHT lope.

Pulled the IAC, tapered socket in a clean shop rag, in the IAC bore, TIGHTLY, but might have still let some air by???.

CL idle at 1475, steady, occasionally touching 1500.

[Schrade]

Well, first there was a moth, and now, an O-RING!!! (except I got the moth with the Shop-Vac)

It was idling at about 2,300, and I pulled the IAC, to put my finger on the IAC-to-plenum inlet, to MAKE SURE I had a seal.

A tip: DON'T DO THAT.

Never even saw the O get pulled; it was so fast. She never even hiccuped. I smelled a puff of burning rubber, and saw the missing O at the same time. By the time I shutdown, and smelled the exhaust tips, I couldn't even tell which side took it.

http://i149.photobucket.com/albums/s50/kimber47/Smileys/fainting.gif

Anyone wanna' buy a Z? Complete with documented F*^#@-ups!!! I might even pay ya for removal...



Anyway, I got a new O-Ring at Advance, same size, slightly fatter, plugged it in, and everything SEEMS like it was before. Idling about 900, occasional lope up to 1,000, down to 825.

Would the burned rubber foul the O2 sensor? DM O2 readout didn't show anything different after the O pulled (I had watched O2 readout before).

[Franke]

Got it there Dom (too much 'life' in the way here)...

Cold idle perfectly smooth [high] @ 825...

...waiting CL here.............


Crept up to 900 post 4 minutes; still smooth....

7 minutes, still OL, but now an IRREGULAR, occasional slow lope, 775 - 925...

Still waiting CL.


CL; 850 - 950, more REGULAR LOPE (screenshot in a moment here...)

https://lh4.googleusercontent.com/-5YJuT-lhbCw/UpzetHgPWII/AAAAAAAADCM/As3rjv9hJI0/s1280/HPIM7599.JPG

Schrade, in the above quote you indicate Open loop idle issue. Correct?

[Schrade]

Schrade, in the above quote you indicate Open loop idle issue. Correct?

No Franke; it had gone to Closed Loop about a minute before...

It ran smoothly, although high, and just before CL, it began a mild lope - 25 - 50 rpm swing, then increased as it hit CL.

Why? What do you see?

I edited that post as it warmed up.

[Schrade]

Ok - FSM irregular idle diags flow chart -

#1 vac leak [no?]
#2 ECM ground NO WAY...
#3 throttle linkage NO WAY
#4 low FPR vacuum [no?]
#5 IAC...

Does DataMaster have 'IAC driver' capability?

[Franke]

Ok. My error on open loop. Sorry to mis-direct on that.
Datamaster is not able to drive the IAC as it is just a diagnostic tool to show what is going on with various sensors and parameters. You will need a tech 1A tool or a Mastertech 3100 to operate the various components and simulate sensors etc. It is also possible to simulate most of the various sensors and drivers electronically if ya know what function they perform and how they do it.
So it appears at this point that the CL threshold is reached and then the idle begins hunting. Does Datamaster show a steady IAC count? Is it steady at 0 or approx. when in OL? Does it move around a lot in CL at idle. I looked at my DM files and IAC was 0 in OL and CL with 725-750 RPM idle speed.

[Schrade]

Anyone got a Tech 1 that I can borrow?

I'll forward full cost Money Order up front, and you can return however much is appropriate after I get it back to you there...

PM me on it if you can...

[Schrade]

Alright; IAC blocked TIGHT (cold motor)...

Idling @ 875, smooth as silk...

Post 3 minutes - loping irregularly 125rpm's, sometimes still very smooth, from 825 - 950, still OL...

Now CL; started about 200 rpm lope IMMEDIATELY when it went CL...

2 minutes CL; settled down with only a 75 rpm lope - 900 - 975...............

3 minutes CL; smoothed out real well - 950 - 975.

5 minutes CL; now holding 975 tight as a drum.

9 minutes; now loping 900 - 1075 rpm's

12 minutes; now loping from about 875 - 1125. Shutdown...

Thoughts?

[XfireZ51]

Alright; IAC blocked TIGHT (cold motor)...

Idling @ 875, smooth as silk...

Post 3 minutes - loping irregularly 125rpm's, sometimes still very smooth, from 825 - 950, still OL...

Now CL; started about 200 rpm lope IMMEDIATELY when it went CL...

2 minutes CL; settled down with only a 75 rpm lope - 900 - 975...............

3 minutes CL; smoothed out real well - 950 - 975.

5 minutes CL; now holding 975 tight as a drum.

Chuck,

OK doesn't look as there is a vacuum leak however, it sounds like the throttle blades may be too far open or allowing some additional air. I assume the TPS is at ~.55v. Now if you can back off the throttle stop 1/2 turn and see if that makes a difference. Leave the IAC port blocked.

[Schrade]

AND my IAC block; a 13mm socket with masking tape came out MUCH easier than it went in.

So that might account for the lope when it went CL, warmed up, with IAC bore opened up by heat. But it still never went below 875, OL or CL...

[XfireZ51]

Yeah so I think it may be time to look at how the throttle blades are situated in the bore. It doesn't take much.
You removed the primary throttle as well as the secondaries? Can you try pushing on throttle lever itself to see if you can close throttle further manually?

[Schrade]

Yeah so I think it may be time to look at how the throttle blades are situated in the bore. It doesn't take much.
You removed the primary throttle as well as the secondaries? Can you try pushing on throttle lever itself to see if you can close throttle further manually?

I did NOT remove the primary shaft or the primary butterfly.

I cannot manually pull the secondaries closed any further.

Just got off of the phone with Marc; he suggested something I had actually thought of - blocking the secondary ports in the TB. He said if rpm's then go down LESS than 100 rpm's, then the TB is fine.

If the rpm's then drop MORE than 100 rpm's, then it needs attention.

[XfireZ51]

I did NOT remove the primary shaft or the primary butterfly.

I cannot manually pull the secondaries closed any further.

Just got off of the phone with Marc; he suggested something I had actually thought of - blocking the secondary ports in the TB. He said if rpm's then go down LESS than 100 rpm's, then the TB is fine.

If the rpm's then drop MORE than 100 rpm's, then it needs attention.

Makes sense. Have you checked throttle blade clearance in the bores? Also, if you have motor running and blip the throttle, how does motor behave returning to idle?

[A26B]

I'm going out on a limb here.....

Before you remove your "ticket stopper"

unplug the TPS to keep it out of C/L just to see if the ECM is inducing the idle speed based on errant readings, such as vacuum leaks. An engine can still run pretty smooth, although idling high from vacuum leaks.

Assuming the idle speed is still high, start checking for vacuum leaks in not so normal areas, using a propane torch with a rubber hose on the end (remove the burner tip & put the rubber hose on the small pipe from the valve)

Check around each injector where they fit into the injector housings, the T/body shafts where they fit through the throttle body, the Dual PCV hose system, from the inj hsngs, all the way into the plenum, the connectors to the 2 hoses into the plenum under & behind the t/body area...... and anywhere else you can get to, including all of the intake gaskets joints.

[Schrade]

The 'Ticket Stopper' dropped my rpm's to 475, STEADY. although rough, like a cammed motor.

Looks like I blew the TB re-assembly. I could NOT see light through the secondaries, but, the Ticket Stopper doesn't lie.

I'll cut out the IAC opening, and see how that effects idle, before shipping the TB off to Marc for a re-work.

Thanks again there Dom, for the phone time there - LOOKS like this thread is about ready to close.............


ed.:
Just saw your post here Jerry; got it. Should I leave the IAC port blocked as well, before doing your test? She would barely run as it was, and actually DID cut off after about 7-8 minutes, while on the phone with Dominic there...

[mike100]

I could probably use a rebuild on my throttle body also, but my solution was to restrict the PCV hose back to the plenum. I y-ed the hose circuit to a filtered can so the PCV can still flow out in volume during hard accel. But it did drop the rpm's 100 or so at idle and got some positive IAC counts.

seems to be a common thing on these engines.

[XfireZ51]

Sounds like an LT-5 idling. Who knew?

[A26B]

Looks good! Glad you are getting it sorted out.

[Schrade]

...and then again, perhaps I did NOT blow the TB re-assembly.

I pulled it, and took a close look in the TB 2' bores. There was some particulate jam HOLDING OPEN THE SECONDARIES, surely enough for a vac leak through them... And I had never worked the 2' s, such that they pulled through.

:confused:

Looked like tiny grains of sand, Black. Where it came from, I cannot guess. I thought I had every little piece spotless sterile clean since the beginning. Even conscious of grit falling off of my sweatshirt sleeves (you learn about that when you spend 5 weeks polishing a Black '94 by hand - 2000 grit, rubbing compound x 3, polishing compound x 4, 5, wondering where new swirl marks come from).

So the TB is re-cleaned. Ready to bolt back together again...

[Schrade]

Re-assembled, TB 2' bores cleaned (again), idling OL @ 750...

...awaiting CL.

PLEASE - let's bury this thread...

I KNOW that the Cruise lope was the vac leak at the under-plenum vac connector........

Only the hesitation was the original issue here...

Showing CL @ 138 coolant temp ??? Heat on 90'; heater fan pegged...

Still idling 750, 153', CL, should be lower with pump load for automatic tranny...

I bumped up the throttle; she wouldn't drop back down below 1,400.

^&%* :censored:

Shutdown; tried to work the throttle, it was stuck. Broke it free, fired it, and the went right up to 3-4krpm's. Shutdown. Binding somewhere here...

Pulled the accordion, and the primary is stuck open.

???

Closed the primary, and she's got a swing - 750 - 925. IAC readout '0'.

Thought the fouled secondaries might have been the answer, but apparently I DID blow TB re-assembly here...

[Schrade]

I'm going to be a 'poser' for a while here...

I'm gonna' re-install the 'Ticket Stopper', since it idles perfect in that manner, do 100 miles or so, check everything out - Cruise, hesitation issue, then send the TB off to Marc for a re-work here...

SO far, everything else BEHIND the TB is perfect.

Any suggestions?

[Franke]

Send it to Marc for a first class rework. There is definitely something wrong with it. You didn't adjust the primary throttle plate so unless there is something mechanically wrong with the return mechanism (spring and linkage) it should close down to idle stop.
You did say in the previous post that there was some black gritty jam preventing the secondary's from closing all the way did you get that cleaned out? Did the TB work ok off the car as far as mechanical operation? No binding etc?

[Schrade]

The 1' throttle binding was the TB coolant crossover tube that I routed over the A/C compressor. It had jumped a casting ridge on the comp. Fixed.

Prepping a road test with the 'Ticket Stopper', to confirm Cruise, and check the hesitation issue............

[Schrade]

Spun up again, primary free from binding, spinning like a top - with the restrictor gasket.

Road test for the cruise lope, and check the hesitation...

EXCEPT FOR A FRESH PROBLEM - BLINKING A/C CONTROL.

http://c1.cowcow.com/img/4-15519436-0-1-1

Recycled battery power, started up, no flashing, then flashing, now it's steady again.

No SES in DIC, no DataMaster codes.

Would this store as a CCM 'H' code, for display in LED dash?

Anybody?

[Franke]

Schrade, if you think you have a fault code check FSM page 1C1-2 diagnosis. Tells you how to check.

[Franke]

Schrade, how did the road test come out on the primaries only? Hesitation gone @1.5% idle?

[Schrade]

Schrade, how did the road test come out on the primaries only? Hesitation gone @1.5% idle?

What's up Franke...

I did a few laps around my neighborhood, then 16 miles round trip to get Safety Inspection - that's a go, no problem.

Hesitation, observable under light throttle, is NOT gone.

The same hesitation that's evident at LIGHT rpm increase from idle is (and was before) evident in Reverse, and in Drive. Under light throttle, it is (as was before), evident as it shifts, and begins rpm climb again.

I cannot accept a vacuum problem, or mechanical problem. It HAS TO be electrical, related to the auto controller module, and the circuit that's singing, as TPS BEGINS range of motion (the 'singer', is in the tranny). Tranny controller diagnostic shows no tranny controller codes. Tranny shifts perfectly, and responds to changes in setting as well.

Everything NOW, with the 'Primary Only' gasket in place, is the same as it was before the plenum pull, with secondaries operational (except for the dirt).

And the Cruise lope, although I didn't engage Cruise, I'm sure is still there, and I'm certain it's also related to the hesitation / TPS circuit.

[Franke]

Did the HVAC issue go away?

[Schrade]

Did the HVAC issue go away?

Yeah - had to be a fluke. Problems never 'go away' otherwise...

I'm gonna' get a vid of the singing TPS, and try to get feedback from TCI and RPM Transmissions.

[Franke]

Yeah - had to be a fluke. Problems never 'go away' otherwise...

I'm gonna' get a vid of the singing TPS, and try to get feedback from TCI and RPM Transmissions.

I'm not exactly sure of what you mean by "singing ckt TPS". Are you hearing something or reading something electrically near the trans?

[Schrade]

I'm not exactly sure of what you mean by "singing ckt TPS". Are you hearing something or reading something electrically near the trans?

Yep - as the TPS goes range of motion, something in the tranny buzzes. Pitch changes in the buzz, as the TPS arm swings. ONLY Closed Loop too - has something to do with some circuit gettin' energized in CL.

When I un-hook the power to the tranny control module, it does NOT happen.

The shop that did the tranny said it was probably a shielding issue, related to Fluid Pressure Solenoid. Pffft. SOMEthing in the install in not 100% correct, but again, no trouble codes in the programmable tranny controller. It even calibrates for 0% TO, and 100% TO, in it's own Setup Wizard, on the handheld interface for the controller.

http://i.ebayimg.com/00/s/Njk5WDc5OA==/$T2eC16JHJGoE9nuQe%28FYBR%21HH58-Yg%7E%7E60_35.JPG?set_id=880000500F
http://cdn.speednik.com/image/2012/05/handheld03-220x145.jpg

Probably time to let this thread drop; maybe resume the 'Hesitation' thread 1990 Throttle Hesitation (http://www.zr1.net/forum/showthread.php?t=21259), FROM which Darryl chopped off for THIS thread... Top end is done - pretty sure it's done right (except for getting the TB to Marc, and re-installed).

[orthodoct]

Mine came off in two pieces and was ROTTEN: Jerry is THE MAN!

[Billy Mild]

Did you find your solution for the idle issue?

[Schrade]

Did you find your solution for the idle issue?

No I did not Billy (although it's not an 'idle' condition) - it's an issue that manifests @ 1.6 - 2.4% TO.

Marc H said the 'lope condition' that comes in @ 1.6% TO, and that continues from 1.6% - 2.4%, is a condition that "ALL 7,000 LT5's have".

I don't agree, but he knows more than me.

So until I can properly read AND write to the memory & calibration module, the 1.6 - 2.4% TO glitch is still there. Kind of a bitch at in-town driving / low throttle. But I know that all else is clean and in good burn order...

And the 2nd TB block when removed put back in about a 75 rpm swing, in DM, that was not there WITH the block. Block made rock steady 675 rpm's Open and Closed Loop.

When I get the hang of coding, I'll put the block back in to eliminate air leak in the TB 2nd holes, which is really negligible, as far as tuning.

[orthodoct]

I used CPU heat sink paste, used a finger to coat thin film over entire surface, torqued down in three steps, cleaned excess at margins with a q tip. Idea is to transfer heat from heatsink surface on underside of ignition module to plenum. Covering entire heatsink surface is the goal; can put on too little with result of incomplete transfer of heat resulting in hotspots with potential to burn out IGM, but too much only squeezes out excess when torqued. I play around a lot with electronics and ham radio. KC4NWF

[orthodoct]

I got a 20 grams container from Amazon for about 10 bucks. Will last me a lifetime.

[orthodoct]

Been using Bosch 4503 Platinum/Iridium with 4 prongs. Didn't think that that I would have to replace them until I got the PCV tube leak; fouled them.