Re: Ruff Idle ,Huge Loss of Power
 

Thankyou very much . Got it yesterday . Now just need some warmer weather to install it .



;)

Re: Ruff Idle ,Huge Loss of Power
 

Installed the float a few weeks ago . Checked it yesterday and it works perfectly . Fuel is now showing full, not 3/4 like it used too when the tank was actually full .
Thanks

Mike

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Re: Ruff Idle ,Huge Loss of Power
 

Got the car up and running with new Summit Racing Injectors . Running smoother but still ruff idle . Smooths out exactly at 2000 rpm . Should it not now idle correctly with new injectors ? I have done the battery disconnect twice now to reset ECM .
What is the next step I should be looking at ?
Be doing a test drive today .
Will post later how it went .



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Re: Ruff Idle ,Huge Loss of Power
 

Which injectors are u using? Is there a number?

Re: Ruff Idle ,Huge Loss of Power
 

ACC- 150821
Car is the same . Test drive went badly .

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Re: Ruff Idle ,Huge Loss of Power
 

Accelhttps://uploads.tapatalk-cdn.com/202...9a2ecdf5a8.jpg

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Re: Ruff Idle ,Huge Loss of Power
 

What year is your car? 93 or later? I noticed the EGR hose on an earlier photo you posted. If so have you checked the EGR valve and it?s control circuit? An EGR valve that is hanging open will cause these types of issues. Refer to your FSM for testing.
H
:cheers:

Re: Ruff Idle ,Huge Loss of Power
 

Yes ok. Accels. That?s what I thought. Any chance u checked coils and wires before putting plenum back on.

P.S. Just a hint. Always order multiple sets of plenum gasket sets from Jerry. 🤣🤣

Re: Ruff Idle ,Huge Loss of Power
 

1995 . No , I did not check the coils . How would I check the coils .
Thanks
Yes , ordering 2 new gasket sets .
Also another has popped up . No AC now . Yikes

Mike

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Re: Ruff Idle ,Huge Loss of Power
 

Check the EGR first...
H
:cheers:

Re: Ruff Idle ,Huge Loss of Power
 

What is the EGR and how do I test it.

Mike

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Re: Ruff Idle ,Huge Loss of Power
 

Tried to find info on the EGR in the manual . We could not find info on a EGR .
In the mean time , I changed the oil and will be looking to see why the AC did not come when it worked last time I pulled the plenum to change the FPR .

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Re: Ruff Idle ,Huge Loss of Power
 

EGR... Exhaust Gas Recirculation. An emissions device used on vehicles from the 90s through (to a small degree) today. It puts exhaust gasses back into the intake to help minimize NoX emissions. The valve should be closed at idle and gradually opens as rpms and load come up. If it stays open at idle and low rpm rough running is the result. You will need an FSM (Factory Service Manual) to test it properly. If your doing any type of work on these cars an FSM is a must have. Internet input, as you have seen from this thread, will send you in a million different directions. Follow the test procedures in the FSM. As a stop gap measure find the EGR valve and the tube that goes to your intake manifold. It goes in right behind the IAC valve on the passenger side of the plenum. Disconnect the tube from the plenum. Find a way to plug the tube (an accordingly sized rubber stopper will do the trick) Then reconnect the tube to the plenum. Please make sure that whatever you plug it with can?t be sucked into the plenum! If that solves your problem your EGR is the issue. Usually they stick open when they go bad. But please... get an FSM and read up on the various LT5 systems. There is also a commonly available training manual that does an excellent job of explaining the various systems. I believe LGAFF sells them on CD.
H
:cheers:

Re: Ruff Idle ,Huge Loss of Power
 

Wow . Thanks
Yes I have the FSM , 2 huge red books . Thanks for that very infomative info .


Mike


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Re: Ruff Idle ,Huge Loss of Power
 

Could you record some video/audio to demonstrate the symptoms you are experiencing?

Re: Ruff Idle ,Huge Loss of Power
 

Yes I can . I will do that tomorrow .
Thanks for the help guys

Mike

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Re: Ruff Idle ,Huge Loss of Power
 

On a related note I just changed plugs on my 94. I bought it awhile ago, but had it in hiding from the wife for longer than normal. I changed plugs for the first time on this car and bought a few different sets. I pulled out some NGK Triex5 I think. I think an older plug of there. It was running fine but I am doing all the maintenance so I know where it is. I replaced these plugs with NGK Iridium plugs and ran fine for a few days then noticed a stumble turning into my driveway. Seems to stumble at times below 2000 rpm, more pronounced at 1000 to 1500. Idle didn't seem quite as smooth but after reading this analysis I might first change plugs, but also check pressure and fpr.

Re: Ruff Idle ,Huge Loss of Power
 

I already have LGAFF CD but I can't find the dam thing . I bought that CD even before I got the car . It's here somewhere . Will keep looking or just buy another one . Completely forgot that I had it .

Re: Ruff Idle ,Huge Loss of Power
 

Everything you need should be in your 1995 Factory Service Manual.
If I had one I could point you i the right direction.
H
:cheers:

Re: Ruff Idle ,Huge Loss of Power
 

Oh ,, you mean the big read Books ! Yikes ... There a bit of a read indeed .

Will figure it out eventually . Not like we can go any where right now so in no rush .

Bugs me that I can't find the CD . It will pop up somewhere in the house one day

:-D

Re: Ruff Idle ,Huge Loss of Power
 

Sorry , did not have time to do it . I will try make a vid tomorrow .
Hoping tapatalk lets me upload it .

:)

Re: Ruff Idle ,Huge Loss of Power
 

Well I knew it . I finally found the LAGFF DVD set ... Hidden in an old briefcase .
;-)

Re: Ruff Idle ,Huge Loss of Power
 

I'm interested in hearing the engine to determine if all 8 cylinders are firing.

Did you verify that each HI-TENSION lead is providing a signal to its matching plug?
For example, if one coil is failing, 2 cylinders will go off-line.

Did you verify that each primary injector is getting a (-) signal from the ECM? One failing or partially failing injector or (-) signal to an injector will be very noticeable at low RPMs.

Re: Ruff Idle ,Huge Loss of Power
 

Morning . Can you tell me what tools I need to do these tests ?
Lots to learn with these beasts indeed

Thanks

Mike


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Re: Ruff Idle ,Huge Loss of Power
 

https://www.youtube.com/watch?v=fEXF...ature=youtu.be


When the tac reaches 2500/2700 rpm the engine surges to 3000

https://www.youtube.com/watch?v=io-9ucGfg4I

Re: Ruff Idle ,Huge Loss of Power
 

The fans turn on when u first start the car?

Re: Ruff Idle ,Huge Loss of Power
 

No ,,, that's the garage AC running . Only thing I hear is the Vacuum pump and its very tight and only runs for a second or 2 . I found a huge leak underneath the plenum and had to mod the rubber connection with my previous plenum pull . .

Re: Ruff Idle ,Huge Loss of Power
 

At the risk of sounding silly, and Im not trying to be condescending, but I didnt see anywhere in the thread where you had replaced or at least ohmed out your ignition wires or checked your coils.. unless I missed it... just a suggestion..

Re: Ruff Idle ,Huge Loss of Power
 

Your not being silly sir . Pretty new to this . No I did not check the wiring and I have no experience as to how to do it . Learning as I go making lots of mistakes along the way .
Ordered more gaskets for a plenum pull . Getting pretty efficient at plenum pulls at least .
Looking into the emmisions first before another pull .
What equipment do I need to purchase to make sure the coils are working correctly .
Thanks for the input .
Lost without the help of you guys on this forum and Mr Haibeck


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Re: Ruff Idle ,Huge Loss of Power
 

Just a quick list of what I have upgraded or changed so far .
New fuel filter , twice . First was full of rust so thought a second switch out would help grab any more crap.

Installed new serpentine belt

Found and fixed large vacuum leak under plenum

Installed a new IFPR

Installed new Accel Injectors

Installed new spark plugs

Car only gets High Octane non Ethanol Shell 91

That's the list so far

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Re: Ruff Idle ,Huge Loss of Power
 

I have been reading / watching this thread with interest. Not trying to hijack it as I have a similar problem that has just emerged. Bought a 94 ZR1 awhile back and was stored for awhile, so I was doing maintenance, oil, plugs, filter etc. and after changing plugs noticed a stumble at low rpm's. Below 2000 was where it was happening. Car had NGK TR5IX plugs in it when I got it and I put in NGK BKR5EIX plugs and after about 50 to 100 miles the stumble started. It did not have a stumble with the original plugs, so I changed out the plugs this morning, they were a light gray to slightly white in color already, so I switched to a set of AC 41-800 plugs. I just came back from a short ride and the stumble is worse. I checked the fuel pressure on the engine and prior to starting it is basically 53lbs. I have waited awhile and it seems the pressure is holding, so I think the FPR is OK, I haven't changed the fuel filter yet and know I need to. Is it the heat range of the plugs possibly or probably a somewhat clogged fuel filter? Filter looks like a pain to change.

Re: Ruff Idle ,Huge Loss of Power
 

ZR2,

So ur saying the motor had a ?stumble? or miss at idle w original plugs, then developed a stumble with the EIX and AC plugs? Is that on acceleration, or just cruise? The 405hp motors I believe were supposed to be gapped at .050? while the 90-92 were .035?. The 5 heat range may also be a bit hot especially if u r first sorting the motor out.
Need some more detail on the issue.

Re: Ruff Idle ,Huge Loss of Power
 

To check plug wires:

Method 1 is to use an inline spark plug tester. Test one lead at a time. Connect one end to the incoming HI-Tension lead, the other to GND (normally the other lead goes to the spark plug but this is likely not possible on the LT5 due to the deep plug shaft). The tester will light when high voltage comes down the wire as you turn the engine over. Available anywhere including Amazon. 2 testers cost under 25 dollars.

Method 2 involves removing one lead at a time and gently inserting a screwdriver completely into the boot of the HI-Tension lead (don't damage the connector). Place the driver over the plenum with about 1/4 - 1/8" of gap between the plenum and the metal part of the screw driver. Upon cranking, you should see a spark jump from the tool to the plenum.


BTW - Before buying any parts, this should have been your very first test. Let us know your results.

Re: Ruff Idle ,Huge Loss of Power
 

Hmmm.....One cylinder could be off line due to fuel starvation. It could be an ECM issue since you've already changed the injectors.

After ruling out your ignition system by checking the HI-Tension leads, you might need to pull the plenum (again) and check your primary injector leads. Learn where cylinder 6 is.

Also - check out this thread:

https://www.zr1.net/forum/showthread.php?t=31783&page=1

Re: Ruff Idle ,Huge Loss of Power
 

Macroblock, I am a different car and issue from the original thread starter. With the original plugs it did not have a stumble. I was updateing everything just doing my maintenance and when I replaced the plugs the 1st time with the NGK BKR5EIX plugs after about 50 to 100 miles I would say the car developed a low speed / low rpm stumble. Mainly at low rpms 1000 to 2000 maybe. nothing at higher rpms. Today I took out the plugs, yes #8 also, what a pain, and replaced them with some AC Delco 41-800 platinum plugs and sure enough the stumble was still there, but actually worse. I checked the fuel pressure after reading this current thread and it was at about 53 lbs with the rail pressurized but not started. It held to 30 lbs ish after 30 minutes or so. Car idles fine, just when a bit of load is put on it below 2000 it stumbles. I think the heat range of the NGK plugs was probably too hot by 1 or 2 ranges, but I think something else is going on. Car doesn't seem to be missing in the traditional way.

Re: Ruff Idle ,Huge Loss of Power
 

Stumble is on acceleration not cruise. If I were cruising the car is fine, just under load.

Re: Ruff Idle ,Huge Loss of Power
 

Sounds like a cylinder or two are off-line. Any fault codes?

Verfiy the ignition leads as detailed in this thread. Afterwards, you will need to verify your injectors and/or the (-) feed to the injectors from the ECM.

Re: Ruff Idle ,Huge Loss of Power
 

Thanks for the info guys . Yes , bad mechanic here . I had concerns doing a sparkplug screwdriver test might fry something so I never attempted that one
.
Thanks

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Re: Ruff Idle ,Huge Loss of Power
 

You should encounter a stumble attempting full throttle at the lower RPMS you describe.

When these parameters are met: Coolant and Oil Temperature is 68F or above and System voltage is 10V or above Power Key on, and NO SES Codes, the ECM will signal the ports to open and wait for .5 second before turning on the secondary injectors at specific throttle vs, RPM. As the secondary injectors share the same drivers as that of the primaries, the pulse width signals are halved when the secondaries operate.
As shown in the diagrams (below), there are three different styles of driving which will operate the port throttles:
1. Ref. line A-B. Constant throttle position with a rising rpm. At the point the arrow crosses into the 'Port Throttle Opening Region' (top left shaded area) the port throttles open and the secondary injectors start firing.
2. Ref. line C-D. Constant rpm with increasing throttle position - logic as above.
3. Combination of the above: i.e. increasing throttle and rpm - logic as above.

The TXT attached file has the graphs of Throttle Position vs. RPM

My 90 stumbles slightly when I put my foot to the floor below 2000. Hope this helps.

Re: Ruff Idle ,Huge Loss of Power
 

Lou,

Stock cal has a delay of .3sec.