Ruff Idle ,Huge Loss of Power

[lfalzarano]

My iWatch runs a little bit faster Thanks for pointing that out.

I pulled that tech info from the Corvette Forum.

[ZR2]

My stumble be a stumble ! !! Maybe coincidentally it was shortly after changing plugs. I did use some dielectric grease in the spark plug boots, which I normally don't do. Since it is non conductive I don't think that is an issue. Of course once I tested the fuel pressure the Schrader valve started to leak. I haven't looked at that but ?rdered a new valve. Need to get it sorted out as I love driving this thing. Just love shifting gears. I think I will do the fuel filter as I ran a substantial amount of cleaner through it last tankful. I was going to change it anyway, so I will change it and go from there .

[Tripler]

Did a spark test a few times actually to make sure and #8 is very weak compared to the rest . Found a way to get a spark tester hooked to the plug so all had a nice full colour accept #8 .
I removed the evaporator coil cover to get to #8 plug a lot easier and placed a cardbourd over the coil so not to bend the fins accidentally .


Mike

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[Macroblock]

ZR2 and Tripler - We gotta do process of elimination to narrow it down.


ZR2 - If you suspect it is a plug issue, you might want to remove one plug wire at a time and run the engine to isolate the cylinder that is possibly acting up. If you pull a wire off and there's no change in the idle, you've isolated the faulty cylinder.

Tripler - If #8 is suspect, pull the plug wire and run the engine. If the engine idle is not affected by 8 missing, likely something is amiss with 8.

Verifying the spark to all 8 cylinders is straightforward. Testing the injectors and the ECM transistor (-) drivers to the injectors is a bit tricky.

[Tripler]

Originally Posted by Macroblock

ZR2 and Tripler - We gotta do process of elimination to narrow it down.





ZR2 - If you suspect it is a plug issue, you might want to remove one plug wire at a time and run the engine to isolate the cylinder that is possibly acting up. If you pull a wire off and there's no change in the idle, you've isolated the faulty cylinder.



Tripler - If #8 is suspect, pull the plug wire and run the engine. If the engine idle is not affected by 8 missing, likely something is amiss with 8.



Verifying the spark to all 8 cylinders is straightforward. Testing the injectors and the ECM transistor (-) drivers to the injectors is a bit tricky.

Thankyou Macroblock . I will give that a shot tomorrow and let you know .

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[ZR2]

I agree. I have been redoing a house to get it on market for sale, so time wise I need to find the time. Of course when I tested the fuel pressure the other day to see if the FPR was acting up and if I had the proper pressure the schrader valve needle starting leaking........so I ordered a couple of them and some AC Delco plugs based on a few recommendations here. It is odd it happened after the plug change, but **** breaks I guess. I think what I will do is 1st change the fuel filter and see where I am. Then maybe check the plug wires by pulling off one at a time and see what happens. I got a feeling that this lovely motor want me to pull of the plenum and freshen her up with new injectors coils and wires etc.....but before her makeover I will see if the simpler items have any effect. I just gotta remember....Air......Fuel......and Spark. I had a 91 ZR1 that I bought from a dealer in Washington State. Thats what drinkin on a Friday night on E Bay can do for you.....ask me about shipping to the east coast!!!! He wasn't the most honest, it was on E bay about 4-5 years ago. It was a nice car, but it had bad secondary injectors, a few of the Bose speakers were blown and one of the Low Pressure Tire Sensors was always on, so I learned the hard way to take the plenum off and I replaced the injectors with FIC injectors. I did it 3 times in a matter of days......one time big vacuum leak, another time a big coolant leak and the 3rd time was the charm. Definitely ordered multiple gasket sets from Jerry's and the thicker plenum gaskets. It ran really hard once I was done. We'll See and I will report back in. Thanks for everyone's help in advance.

[Tripler]

Pulled the #8 plug wire and saw no difference when it was plugged in or not plugged in . #8 is kaputz I think .


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[Macroblock]

Tripler - sounds like cylinder #8 is off-line. Its waste-spark partner is cylinder #5, so try the test by removing that Hi-Tension lead to see if doing so has any affect.

If #5 and #8, together or one at a time, have no affect on engine idle, then it could be an ignition coil, the ignition module or the wiring between the two.

If only 8 has no affect on idle, then it's possible the primary injector at #8 is not pulsing. This could be a faulty injector, the ECM or the wiring in between.

[Tripler]

Originally Posted by Macroblock

Tripler - sounds like cylinder #8 is off-line. Its waste-spark partner is cylinder #5, so try the test by removing that Hi-Tension lead to see if doing so has any affect.



If #5 and #8, together or one at a time, have no affect on engine idle, then it could be an ignition coil, the ignition module or the wiring between the two.



If only 8 has no affect on idle, then it's possible the primary injector at #8 is not pulsing. This could be a faulty injector, the ECM or the wiring in between.

Pulled #8 and #5 at the same time and it idles ruff and sounds the same .


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[Tripler]

Also someone had asked before if the fans were running when I start the car and I confirmed today that they do not run on startup

;-)

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