runs rough and I smell gas help!!! - Third Generation Forum

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runs rough and I smell gas help!!!
Monday, July 30, 2012 1:32 PM
OK this is what's been going on.
A while back I had my computer flashed and it ran great!
Unfortunately now it seems as though the #5 injector driver is not working correctly.
This is my reasoning.
Just to make it clear my cavalier now has a 3400 out of an Alero.
It's been idling high off and on for a while now. I thought it was IAC but that did not fix it, so I just lived with it. every now and then it would idle so high that I would just shut it off and restart the car and I would be ok for a while. OK, that may or may not be related but now when I pull up to a stop sign it runs rough and I can smell gas but I can't find any leaks. So today I decided rather than risk washing out one of my cylinders I would take it apart, since I have yet to hook up the data link connector to the computer. I pulled the fuel rail and had my son crank the engine for me while I watched the injectors. Right away I noticed the #5 injector was not misting like the others it was gushing like it was full open so I thought OK, I need an injector, so I took one from a known good running engine plugged it all back together and had my son crank it again and it did the exact same thing so I thought OK, I'll switch injectors again with one that was already on the fuel rail, basically I switched the wires around and now that injector would gush fuel like there was no tomorrow. I traced the wire back to the computer and it all looked fine. Key on engine off; I seem to be getting 6 volts on the black wire and 12 volts at the positive wire at the injector and it seems to be just like the other injectors as far voltage is concerned. I also hooked up a noid light to watch the injector pulse and it seemed to be just like the other ones but my light is for an older throttle body injector I'm no sue if it even means anything.

Basically I was wondering if any of you ever heard of anything like this happening or if you could give me any advice that would be great! If need be I might get another computer flashed.

Thanks guys!

Re: runs rough and I smell gas help!!!
Monday, July 30, 2012 4:27 PM
I can't say why that one injector spot would be the only one doing that, but you should not be getting voltage to both wires. The computer grounds the injector to fire it, so with the key on, engine off, you should get nothing from the odd colored wire (most likely every injector has a pink wire and an odd color, and pink is positive). It almost sounds like you're having a grounding problem, but it still doesn't explain that one driver acting up when the others are not. It may still be in the computer, so I might try another computer as the next step.

Good luck with it.




I'm cleaning out my garage!
Billet upper mount for 3rd gen V6 swap!


Re: runs rough and I smell gas help!!!
Monday, July 30, 2012 5:19 PM
^ True. The computer fires injectors by shorting to ground. So either you have a short, or the ECM is f*cked.





i find it amusing that SHOoff has nothing better to do but follow me around & be an unhelpful dick in even cross-forum. - Jon Mick
Re: runs rough and I smell gas help!!!
Monday, July 30, 2012 6:11 PM
thanks for the input guys!

I just came in and and read what you wrote. It turns out it was the wiring going to the injector. I just said the he!! with it and ran a new wire, I had nothing left to lose. side note my cheap Ebay Tach works perfect now!! LOL go figure.
I always thought it had an electrical issue and now I solved it. Thank God!!! did I mention it runs better than it ever has before!!!
I'm going back to the track this Wednesday and hopefully it goes faster than before, 14.8 sec @ about 94MPH quarter. I also have slightly taller and wider tires on it now in a 16" rather than my 14" tires. we'll see! I'm looking for 14.5 @ 95MPH

Thanks for the input you guys were right on thanks!!!
Re: runs rough and I smell gas help!!!
Tuesday, July 31, 2012 6:03 AM
Good to hear, man. Sometimes it's just the tedious tracing that you have to go through, and there's no quick answer, but knowing exactly how everything functions makes a difference.




I'm cleaning out my garage!
Billet upper mount for 3rd gen V6 swap!


Re: runs rough and I smell gas help!!!
Tuesday, August 28, 2012 9:11 PM
which wire was it exactly?

color wire?

have an issue like this on a buddys 97 GP with 3800 i think its the #5 injector as well

swapped it out once with a known good one and was ok for a while but its messing up again

the big fancy expensive snap on solus scan tech computer we have said #5 cylinder miss

so thats where i went to, with it

now it also has a big problem of sputtering no power bogging when trying to accelerate going down the road and especialy when trying to pass a car on the highway

very bad sputtering power loss something wrong

fuel pressure 45 psi all the time

exhaust not plugged up at all

new wires/plugs etc

faulty 02 sensor signal code, for the second one back under the car

did have faulty TPS code a while back but i cleared it and it never came back

recently the FP regulator on the injector rail(vacuum controlled) ruptured and was sucking in raw fuel into the TB unit

replaced the reg with a good used one

now stuck with this sputtering power loss issue and the solus scan-tech is not helping much








-96 cavalier 2.2 auto 143k miles
Re: runs rough and I smell gas help!!!
Tuesday, September 11, 2012 5:47 PM
The wire I replaced goes directly to the injector from the computer my wiring harness may be different than yours so color may not help but if you open the harness up you'll see where one of the wires from each of the injectors are spliced into one that is not the one I replaced, it's the one going to the computer.

to be honest it sounds like you have a different problem than me.
pull the fuel rail and see how the injectors are pulsing/misting the fuel, that's what I did.
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