another day, another code...

[Kevin]

Swapped ECM's on the zr-1 today and took it for a drive. the car is no long banging when it misses but it's currently running out of vacuum in 5th and setting code 61, which is different then the DIS code it set last time which number I can't remember. I had Marc Haiback check the system at carlise and the pump and actuators checked out fine. However today I get this code...this is getting old, not sure how much more of chasing codes I can take.

[Blue Flame Restorations]

Kevin, sorry to hear of another code to chase. Hope it gets rectified soon.

Brett

[ZZZZZR1]

Kevin

Have you changed out injectors (new SS ones)/ coil packs / spark plugs / wires and fuel pumps?

It's hard to chace down codes unless all the preventive maintenance is done. I can't remember what you said was done...

What's been done to the car in the past 5 years? Anything recently?

:cheers:

David

[GOLDCYLON]

Swapped ECM's on the zr-1 today and took it for a drive. the car is no long banging when it misses but it's currently running out of vacuum in 5th and setting code 61, which is different then the DIS code it set last time which number I can't remember. I had Marc Haiback check the system at carlise and the pump and actuators checked out fine. However today I get this code...this is getting old, not sure how much more of chasing codes I can take.

Pull the seconadaries Kevin.

[Kevin]

Kevin

Have you changed out injectors (new SS ones)/ coil packs / spark plugs / wires and fuel pumps?

It's hard to chace down codes unless all the preventive maintenance is done. I can't remember what you said was done...

What's been done to the car in the past 5 years? Anything recently?

:cheers:

David

New FIC's, coil packs, pumps and filter aren't new but I don't think that's the issue, not getting a fuel code or anything like that, plugs and wires are new as of last year. Talked with Marc and he thought it was a bent pin in the DIS making bad contact when I had the old ECM in the car and had a DIS fault code. Spoke with another friend who thought it was the ecm degrading via heat soak so I swapped that today and ran the car. 1-3 pull hard, 5th ~2500 sets a code 61 but it's no long banging when it stumbles and will still pull but just set a code. Idle is fine, driving around is fine, secondaries in 1-3 are fine, didn't try in 4th, that's way to much "spend time in jail no license insurance will love you forever" speed for me to do on the street.

Marc looked at the car at carlise, the system holds vacuum fine, the secondaries open fine.

Past 5 years... well there was:
02 sensors last year
fuel injectors last year
plugs last year
wires last year
complete ac system replacement this year

and that's what I can remember off the top of my head, I'd have to look at my records to see what else was done but if it was something it wasn't major. Car is stock except for the front calipers/lines, the haibeck chip, and the coplan air duct. I wouldn't mind these issues if the cat had been through 4 shops and multiple engine builds, that's to be expected, but this is a factory car. Sure it's 23 years old but my this is getting excessive. I'm about ready to list it for sale.

[Kevin]

Pull the seconadaries Kevin.

been considering wiring them open and getting a chip burned for it. not sure why i haven't yet.

[Blue Flame Restorations]

PM sent

[tccrab]

Kevin:

Electrical gremlins are extremely difficult to track down and eradicate, especially ones that are intermittent.
Took me better part of 3 years and untold hundreds of $$$ to finally track down to bad fuel injector to ECM contacts because I had stupidly shoved in my Digital Volt Meter's probe to check them when my injectors took a crap.
Sounds to me like you have a similar, although different gremlin.
Start backtracking to all the connecters that you have futzed with over the years.
Betcha you'll find something.

Sometimes it's the simplest things..........

Feeling your pain,


'Crabs

[GOLDCYLON]

been considering wiring them open and getting a chip burned for it. not sure why i haven't yet.

Talk to Dom he did exactly that for a while.

[Kevin]

Talk to Dom he did exactly that for a while.

in talking with my wife I can't see the forest for the trees right now, I'm going to call a friend this week and talk with him and see if he can help me get a better perspective on it. I'd really like to drive a near stock car with it before I did tune them out but I don't think that's going to happen

[Kevin]

talked with marc and another friend and we determined that "The secondary port vacuum solenoid could have an intermittent leak. The plenum needs to be removed to replace it. The secondary vacuum check valve could be intermittent." both of these are apparently rare, what luck I have....

[XfireZ51]

talked with marc and another friend and we determined that "The secondary port vacuum solenoid could have an intermittent leak. The plenum needs to be removed to replace it. The secondary vacuum check valve could be intermittent." both of these are apparently rare, what luck I have....

If you strap the secondaries open, you can either throw in a chip that eliminates secondaries, or put in a plug to the DIFF MAP sensor harness connector so ECM is happy. Problem solved for good.

[Blue Flame Restorations]

Before I bought my first Z, I knew that I would "rip them out" of whatever I bought. As luck would have it, Paul Denhert had already done so. Unfortunately, the other motor I used still had them, so we ripped them out as well. I just didn't want any aggrevation going forward.

Not for everyone but I never seem to hear of anyone ever putting them back in?????

[Kevin]

If you strap the secondaries open, you can either throw in a chip that eliminates secondaries, or put in a plug to the DIFF MAP sensor harness connector so ECM is happy. Problem solved for good.

i was thinking chip + wire, but i'm on the fence. i'd like to drive a near stock car that way but I don't know anyone near by that has it done.

[GOLDCYLON]

i was thinking chip + wire, but i'm on the fence. i'd like to drive a near stock car that way but I don't know anyone near by that has it done.


Kevin this would give you a lot of piece of mind and is simple as wire and a PROM. Even if you decide to sell your car this is a selling point as you will eliminate a reason to pull the plenum in the future for a secondary vaccum issue. its also not permament and can be return to stock by simply pulling the wires and putting the stock chip back in. GC

[Blue Flame Restorations]

Kevin this would give you a lot of piece of mind and is simple as wire and a PROM. Even if you decide to sell your car this is a selling point as you will eliminate a reason to pull the plenum in the future for a secondary vaccum issue. its also not permament and can be return to stock by simply pulling the wires and putting the stock chip back in. GC


Good point, GC ;)

[Schrade]

Vac leaks aren't usually intermittent, are they???

I was wondering right after I got mine last year, if some circuit that's energized in Closed Loop might make such a thing happen, but no one has offered up any confirmation...

[GOLDCYLON]

Good point, GC ;)


I know his frustration a lot of us have been there. Hell my butterflies screws fell into my motor and hosed two valves and a piston.

Felt the same way after replaced my third used cat. Went to headers and High Flow Magna flows cats. There is a time you just do what you need to do.

[Kevin]

Vac leaks aren't usually intermittent, are they???

I was wondering right after I got mine last year, if some circuit that's energized in Closed Loop might make such a thing happen, but no one has offered up any confirmation...

my understanding is that the engine produces enough vacuum to keep the secondaries running under WOT and it's only when you start playing around at part, or full throttle in a high gear and low RPM that you need the extra vacuum to keep thing running. either way this requires pulling the plenum which I'm not comfortable doing. :mad:

[XfireZ51]

I used tie-wraps on the actuators. Since you're pulling the plenum anyway...

[Kevin]

I used tie-wraps on the actuators. Since you're pulling the plenum anyway...

thought about that but was worried about the heat, decided to use wire if i'm going to do it

[XfireZ51]

thought about that but was worried about the heat, decided to use wire if i'm going to do it

I had no issue w using tie-wraps. They were fine for over a year. Just FYI.

[Kevin]

I had no issue w using tie-wraps. They were fine for over a year. Just FYI.

going with wire for piece of mind. i'm sure ties would work but I only want to do this once :cheers:

[Dynomite]

Before I bought my first Z, I knew that I would "rip them out" of whatever I bought. As luck would have it, Paul Denhert had already done so. Unfortunately, the other motor I used still had them, so we ripped them out as well. I just didn't want any aggrevation going forward.

Not for everyone but I never seem to hear of anyone ever putting them back in?????

So....you removed the secondaries violently....what.....were you upset at something :D

I actually left the secondaries in my 90' as it only takes a few minutes to fix whatever is under the Plenum since I have TB coolant totally and professionally removed. Removing Plenum (including the 10 minute Plenum Removal) (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-4.html#post1581663365)

If you are going to remove the secondaries I would REMOVE the secondaries and not tie them open but that is just me ;)

[Blue Flame Restorations]

So....you removed the secondaries violently....what.....were you upset at something :D

I actually left the secondaries in my 90' as it only takes a few minutes to fix whatever is under the Plenum since I have TB coolant totally and professionally removed. Removing Plenum (including the 10 minute Plenum Removal) (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-4.html#post1581663365)

If you are going to remove the secondaries I would REMOVE the secondaries and not tie them open but that is just me ;)


Felt pretty good.....;)

[Schrade]

Wanna' sell me one of your codes?

I need something concrete (besides this headache)...

[KJL]

going with wire for piece of mind. i'm sure ties would work but I only want to do this once :cheers:

Kevin- do you have emissions inspections to deal with? I am a new ZR1 owner and have my plenum removed at the moment and was considering removing the secondaries but read some threads that indicated that passing emissions may be a problem with them removed. I guess if you wire them, once a year you could un-wire and install the stock chip to get through emissions but that would be a pain. I would love to pull all that "stuff" out of there.

[We Gone]

I spoke to Marc H. about removing mine while he was doing the porting, he said leave them in if I had to deal with emissions.

[Kevin]

Kevin- do you have emissions inspections to deal with? I am a new ZR1 owner and have my plenum removed at the moment and was considering removing the secondaries but read some threads that indicated that passing emissions may be a problem with them removed. I guess if you wire them, once a year you could un-wire and install the stock chip to get through emissions but that would be a pain. I would love to pull all that "stuff" out of there.

no emissions here. even if I did, I don't drive it enough to hit the millage requirement to get smogged

[GOLDCYLON]

no emissions here. even if I did, I don't drive it enough to hit the millage requirement to get smogged

Well that's great news

[Paul Workman]

my understanding is that the engine produces enough vacuum to keep the secondaries running under WOT and it's only when you start playing around at part, or full throttle in a high gear and low RPM that you need the extra vacuum to keep thing running. either way this requires pulling the plenum which I'm not comfortable doing. :mad:

Well, actually you're partially right. The engine provides vacuum most of the time, except during WOT. At WOT the vacuum drops to near zero, and the reservoir only pops the actuators open. But, then its the pump's job is to keep them open as long as you're standing on the throttle.

Wiring the secondaries open sounds like a good way for you to go, at this point. It is reversible at any time, and it may reveal some other gremlins in the 'lectric chit' by eliminating the secondaries at least.

Far as keeping the secondaries if the car is subject to periodic emissions inspections go, it would give me pause to contradict Marc. However, I am ignorant of any report where emissions would pass, but only if the secondaries were in place. (Furthermore, the next generation LT5 eliminated the dual runners and went with one injector. What does that tell us?)

In my case, my porting included the secondary runners. So reinstalling the system would involve fabricating new (bigger) throttle plates, (NOT gonna happen), OR a custom gasket that closed off the secondary runner and revert to a stock calibration, long enough to pass inspection...;)

Far as pulling the plenum goes, it is really very simple, for anyone that can walk and chew gum at the same time. You'll need a gasket set from Jerry, and while your at it, you might freshen the O-rings on the fuel rail and the injectors too, if you haven't already.

Make a list of the connections you disconnect for reference later. Drain a few quarts of coolant into a catch can (to be reinstalled after). Then just remove the fuel line block, remove the screws and the PVC line, purge tube, to the TB, the left and right side vacuum connections to the middle of the plenum, and prop the front of the plenum up while you remove the vacuum tube under the TB's "chin" and the two DIS connectors. Then remove the MAP sensor and it's bracket, and un-hook the two connectors at the back of the plenum, the IAC and the TPS and the air temp sensor connectors, and then just roll the plenum over to the drivers side to rest on the wheel well gasket - you don't have to disconnect the throttle cables, unless you are completely removing the plenum for another reason: leave them intact. (However, since it sounds like you're possibly having electrical gremlins, removing the throttle cables to completely remove the plenum to access the electrical connections for inspection and possible cleaning (use a an electrical contact cleaner, and compressed air), might be a good idea.)

Before reinstalling the new plenum gaskets, I lay the gaskets on something flat, like a plywood board, and spray the top (plenum) side with silicone spray. This amounts to a "release agent" which will facilitate the next plenum pull by possibly being able to reuse the gasket once or twice or maybe even 3 times (and counting!) Just make sure both surfaces are absolutely clean; use a utility razor blade or window scraper to get all the little flecks off the two mating surfaces, followed by scrubbing the metal with a rag having been wetted with brake cleaner. (The key is to get the metal absolutely clean, especially of any oil. I prefer the CRC "Brakleen" or one with the tetrachloroethylene/trichloroethylene (red/white can, but NOT the green/white can), i.e., NO residue (read: NO Naptha based crap or gasoline, etc.) to better allow the gasket to adhere to the IH and facilitate future removal of the plenum w/o damaging the gasket.)

And, while you have the plenum off, that would be a good time to remove the two ground lug bolts at the top of the block, in the area under the MAP sensor, and wire-brush the many lugs and the anchoring bolts before reinstalling. Some dielectric grease smeared on the lugs too will retard future corrosion due to exposure to the air and moisture. (It may or may not cure existing electrical problems, but may well head off a couple that were waiting their turn to drive you nuts!:()

Good luck!