Hey everybody, I've been fighting my 1985 Camaro Iroc 305 tpi for the past little bit trying to get it to run right. I was driving home the other day and all of a sudden it just cut out and wouldn't restart. After messing with it I found it wasn't getting spark so I replaced the ignition control module and it fired back up but was running really poorly. It won't idle on its own and it sounds like it's either misfiring or pre-detonating as you rev it up. I believe it's running rich as you can smell a strong gas smell near the front of the car. I pulled off the throttle body and cleaned it because it had a lot of gunk in it, after doing that it ran really good for about 10 minutes then it started doing the same thing. I checked the fuel pressure and it climbs up to a little over 40 when priming and stays right around there while the car is running. The car has new spark plugs, wires, distributor, coolant temp sensor, icm, and fresh filters all around. I'm pretty lost and would appreciate any help!

 

Welcome Aboard!

Check the operation of the fuel pressure regulator. It sounds as it it may not be doing its job, since fuel rail pressure should drop once the engine is started. If it does not, that could explain rich operation.

 

I'll go ahead and pull it off tomorrow and take a look, thank you for the idea!

 

The diagnosis of the regulator can be done in place - No need to remove it for checking. If the vacuum source to the FPR is missing the results could be just as you described.

 

I went ahead and checked it out, the vacuum line is hooked up properly it seems. I pulled it off and the membrane didn't appear to be torn or anything. Is there anything that I could be missing?

 

If the fuel pressure is monitored with the engine running, there should be a drop in pressure when vacuum is connected to the FPR. If that happens, the regulator is functioning and the reason(s) for the rich condition are probably elsewhere. If the pressure does not change, there could be a problem with the regulator or return line.

Is this a stock/fixed regulator, or an adjustable one?

 

Alright I apologize for taking so long I finally got the chance to work on the car. I went ahead and tore everything apart and found that one of my injectors was leaking pretty badly, I went ahead and changed those out for a new set and I changed the fpr while I was at it. Thankfully no more gas smell coming from the engine bay. The car is still running pretty poorly though, when it starts it'll run for about 30 seconds and then it will slowly die out. If I get it to run long enough it will idle fine but the second I start trying to drive it the thing starts to misfire and won't accelerate. I still have no check engine lights as well. Do you all have any ideas for something to look for? I feel like I'm missing something stupid. I appreciate the help!

 

I'm not sure if this would be very helpful but here is a video of what it does when it idles. I'll get a video of it trying to drive after work today if that would be helpful.

 

What was the manufacturer's part number of the injectors which were installed as replacements?

 

I got the 19lb Bosch D3 injectors from Southbay

 

It's probably safe to assume that the flow rates are close enough to the original Bosch injectors to eliminate the need for a custom ECM tune. Did you also install the extension adapters with the injectors?

 

Yeah the new injectors have the extension adapters on them and they fit pretty well.

 

If you can get it to run at all, check the base ignition timing with the EST in bypass.

 

I've had some troubles getting it to idle with the est wire disconnected but I've been adjusting the timing after it dies and then I turn it back on to see if she runs any smoother. It's weird because it seems to run well right off the bat and I can rev it up without any misfires or anything. But if I try to give it some gas when it starts to die off it misfires and stumbles over itself. When checking today I heard a slight hissing sound on the passenger side of the engine. I'm thinking there might be a vacuum leak around there but when I spray carb cleaner around there the rpms don't increase but the car slowly dies off which it does without the carb cleaner. When I get some time I'm gonna take apart the intake again and see if the egr is leaking at all or if one of the injectors isn't sealing right. Is there anything else that could be leaking around there?

 

For what it's worth, my 305tpi did not like the bosch 3 from Southbay at all, I had to get a retuned chip and then it ran fine, just food for thought.

 

When you got the new chip did you have it custom tuned or was there a mass produced "D3" one that you were able to buy? The car didn't run great before the injector change so I haven't even considered that yet. Was your car doing a similar thing before you changed the chip?

 

You're at a bit of a disadvantage since the 1985 model year was a one-off version for 1985 only. Finding a CALPAK and the software isn't as easy as the later years.

https://www.eecis.udel.edu/~davis/z28/

 

Yeah that's one of the things I've heard. I'll definitely keep my eye out though. I worked on the car this weekend and I changed a couple of vacuum lines and I cleaned the egr valve. It seems to be running a lot better but is trying to idle a little low so I'm gonna do a tps and iac set today and see if that helps. I'll let you guys know if it works

 

If the EGR is temporarily disconnected for testing, the results might be revealing.

 

I just got an 88 GTA with a 5.7. The car is running rich, runs rough, and doesn't want to idle. I've changed out the plugs, wires, and the IAC. The only code the car had was a code 36. I changed the relay, and the code and SES light stopped, but unfortunately that wasn't the cause of the issues mentioned earlier. The car idles somewhat in open loop, but once it goes into closed loop, it starts to idle really low, surges, goes low. Does this a few times before dying. We found a disconnected wire under the plenum, and tracing it back, it looked like it was part of the EGR pigtail. I wanted to rule out an open EGR valve because of this find. I was going to pull the vacuum line off the EGR valve under the plenum, block off the valve with a nipple and then run the car. Open to any other suggestions to temporarily disconnect the EGR if what I'm thinking isn't going to do the trick? Thanks!

 

I finally got some more time to work on the car and I found a small vacuum leak which I fixed. The egr seemed to be working properly as well. I went ahead and did a tps and iac reset but the car is still doing a similar thing where it will idle but slowly die out. But if I give it some light throttle for a little bit I can get it to idle on its own. When I got it to idle I went ahead and checked base timing but I found that it wasn't reading anywhere near 6 degrees on the timing marks. I tried adjusting timing but when I rotated the distributor both clockwise and counter clockwise it just ran horrible. I went ahead and cranked the engine to TDC and I pulled the cap off and it seemed to be lined up in the proper orientation with cylinder 1. I did disconnect the wire for the computer timing control that is above the air box. At this point I'm really not sure what could be causing it to run like this but the timing seems like the only thing that is wrong right now. I'm going to try and get a rental timing light to check and see if mine is just broken or if the timing is actually that far off. If you guys have any suggestions I'd appreciate it!