#1 cyl misfiring 97 z24 - Performance Forum

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#1 cyl misfiring 97 z24
Saturday, November 08, 2008 6:55 PM
Hey guys, i need your help. My friend's z24 has a misfire at cylinder #1. we have checked for spark and checked the fuel part and everything seems to be fine.

When the car started acting up, my friend took it to autozone to get the light diagnosed but the scanner was not able to communicate with the pcm. The guy at autozone said that it could be that the wires were cut or some fuse might be blown. The car was taken home and checked by a mechanic. He found out that there was a misfire at cyl1. The guy checked all the injectors and they were fine. He said it could be the white part where the coils are enclosed. We went to the yard and got the whole ignition module + coils. the car still misfired. So, we decided to do our own checks.

We checked for spark at all cyl. and is fine. All cyl have good spark. We took out the fuel rail and did our own tests on the injectors. All the injectors were getting the same bat voltage when cranked. All injectors had about the same resistance. they all had the same spray pattern. This rules out the fuel side and the ignition side. What could be the problem?

When we crank the car, the fan comes on even though it is cold. we unplug injector # 1 while the car is running and nothing happens. If we disconect anyother injector the car dies. If I rev up the car suddenly, the car dies. If I rev it up litle by little it won't die. All fuses are good. We disconected the bat and took the pcm fuse for about 20 min and still the same problem. Im going crazy!!! I'm starting to believe that the pcm might be bad or they might be something internally wrong with that cyl. We are yet to do a comp test and rule out that possibility as well! what do you guys think it might be?


plugs and boot inserts are brand new.
the car is a 97 z24 auto with 90k miles. thanks in advance!




Stock '00
2200 cavy
sedan!!!!

Re: #1 cyl misfiring 97 z24
Saturday, November 08, 2008 7:17 PM
Sounds like you found the proble, already. Injector. Have you pulled the plugs? Compared #1 to the others? Go grab a injector out of the yard and swap it.



FU Tuning



Re: #1 cyl misfiring 97 z24
Sunday, November 09, 2008 8:26 AM
we swapped the injectors to different cylinders. #1 injector (which we thought was bad) was replaced with the #4 cyl injector. we put everything back together and the problem is still in #1 cyl. #4 cyl with the "bad injector" is working properly. we pulled the plug on that injector and the car dies.




Stock '00
2200 cavy
sedan!!!!
Re: #1 cyl misfiring 97 z24
Sunday, November 09, 2008 3:49 PM
we have found the problem. it has something to do with the ignition side of it.
We noticed that when we tighten the idi cover, the car starts misfiring. As soon as we take off the screws and let the car run with the idi cover untightened, the car runs fine. As soon as we try to align the bolts to tighten it the misfire comes back. If I push it down with my hand, the misfire comes back.

At least we now know where the problem is! any ideas of what could it be? wiring? ground? coils?




Stock '00
2200 cavy
sedan!!!!
Re: #1 cyl misfiring 97 z24
Sunday, November 09, 2008 5:20 PM
wow thats strange....add some washers in the mean time


GMR has got nothing on this
Re: #1 cyl misfiring 97 z24
Sunday, November 09, 2008 6:34 PM
is that grounding strape still on the one bolt





JBO since July 30, 2001
Re: #1 cyl misfiring 97 z24
Sunday, November 09, 2008 6:50 PM
The grounding strip is still there. I actually think that the grounding strip is the problem. seems that when the cover is grounded is when the problem happens!




Stock '00
2200 cavy
sedan!!!!
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