Unfortunatly we have been trying to fix my firebird for the last 4-5 weeks. The car is worse now then it was before. Runs like butt, I need some serious help.

This is what happened:

Started noticing in wet weather the car idleing funny, and it acutally shut off once in the rain while idleing. Started it back up, ran badly like it had a vaccum leak.
Started it the next day ran like a champ. Noticed in dry weather coming home ses light started going on and off, car started running rough, had no pick up and i was doing 40 mph. Would not go any faster, so I ver off into a GM dealer so they can hook it up to the computer.

My hubby says no, bring it home and he and our LT1 gu ru Eric will fix it. Well I couldn't remember if the opti had been replaced, turns out the opti was replaceed a little over a year ago, the cap and button looked fine, very little wear, so we put a new MSD blaster coil on it as well. Clint and Eric decide to remove my EGR stuff, it pumps exhaust or freash air into the exhaust I think, its emissions stuff. They take it off, mind you Eric has a OBDI car and mine is OBDII.
So they took the intake off, new gaskets, used RTV to seal the intake on the frount and back, it was leaking oil. So we start it a few times, backfiring, and running rough.

Thought we crossed spark plug wires, so we re-checked they are all correct. Blocked off part of the EGR line on the back of the motor, Eric thought that fuel was building on the cylindars causing it to backfire. Well we blocked it off, started it no backfiring anymore but in Drive or Reverse it runs rough, and in Park it runs "ok", better then in gear. It basically shakes like it has a cam or something is the best way to describe how it runs. It runs bad. So we put the EGR back on the car and no change in how the car runs.



Please any suggestions? Thanks!

Greenfire

 

No there is no smoke of any kind coming from the car.

 

If I understand your story, no one ever bothered to check the SES light.... they just started replacing and repairing parts? It might still be worth getting it scanned, if its running that poorly.

 

Sorry for the confusion, we did scan the computer, the only thing is said was engine misfire. That was before we ever did anything to the car.

 

It sound like it needs new plug wires to me.The fact that it was missing when wet.

 

It has the MSD 8.5 wires on it and they are a year and a half old. New plugs are about 4 months old, NGK TR55's.

 

*Dramatic Chord* OPTI!!!!! *Dramatic Chord*

 

Well then it has to be the optical lense part of the opti, b/c the cap and button are fine, already checked those. Only part left is the lense.



Greenfire

 

Don't just count out those wires cause they are realitivly speaking (newer). I thought the same thing when I had misfiring issues. Had GM check it out. They said opti. This was before I new about these cars. I said rape me. (Change the opti) So they did. Car still miss fired. I decided to get dirty. Found my #7 & #8 Newer plug wires had hairline cracks in them causing a arc. So the dealer said they could not find a problem with the wires and I did find a problem. Ran like a champ since then. Moral of this little story is for you to check them 3 times if needed.
Good Luck

 

If its the optical section of the Opti that is causing the problem (LED emitter/receptor), you will get DTC codes set in the PCM for either loss of high resolution or loss of low resolution pulse signals. Have you scanned for those?

 

Very good point, thanks, we will check all of the wires, you are right they could have cracked, the only side we have taken off and on so many times that the ones connecting to the opti may be damaged. Thanks for the advice.

Greenfire

 

Ya know, I never thought about that, we are going to scan the car again today, the only code it spit out last time we scanned was engine misfire, along with the O2's and the cats, since the car has no rear O2's and cats since I put headers on it.

The opti did get wet while it was being removed, so that maybe the problem right there. Definatly next time this happens who ever is doing the work will have like 5 towels to keep it dry. Also had a friend tell me to cylacone the opti to keep it dry if the water pump ever started leaking.

Definatly a good idea! I'll let you all know what we find out today, then maybe the brain storming will be over

Greenfire

 

Try starting the car at night and looking for arching wires. Maybe one was burned by the headers and you didnt notice it when checking to see none were crossed. If it was the opti you would have been throwing the code from the beginning most likely.

How does the car run when its cold, as in when you first start it up, do the problems occur once it hits closed loop or is it all the time. Does it clear up if you floor it?

 

I realy don't think you can jsut tear the EGR and so on off an OBDII vehicle. The EGR is recirculating exaust gas back into the cylinder to cool the instake charge, the air pump when removed will spike your O2s. The computer is probabally freaking out by now, check the codes and see whats going on there but you may have a problem from the missing EGR and so on.

 

The EGR only runs part of the time, never at idle, never over 3,500rpm, never at WOT. The exhaust recirculation is used to cool the combustion temps, but only under conditions that would elevate them and produce NOx. Many people successfully remove EGR on an OBD-II. All you need to do is address the resulting SES light by programming the eGR out of the PCM. Even with the SES light, it wouldn't cause the symptoms he is getting.
Why would it "spike yout O2s"? The AIR pump only runs for a few minutes at startup to help the cats heat faster. After that, it isn't used and won't affect exhaust O2 levels.

I don't think these are related to his problems.