Howdy everyone.

This is my first post, I have spent hours searching for answers.

My car is an 86 IROC, 305 TPI, auto. It is mostly stock as far as I can tell.

The problem started a few months ago when I got my car out for spring. It started as an intermittent problem where it would start fine but stall IMMEDIATELY. If I held down the gas when I started it, it would run and eventually go back to normal.

The problem started out as a once in a while sort of thing, but got to a point where it always happens.

I checked for codes and got a code 34, so I got a new MAF to test it out. The new MAF didn't make a difference. (luckily I didn't buy it.)

I replaced the MAF power relay, which didn't help. I checked to see if the MAF burn off was working, it wasn't, so I replaced that relay too.

Then the problem changed. It still stalls immediately if I don't step on the gas when I start it, but now it also runs rough, surges, and throws CODE 33, not 34.

If anyone has any advice, I would really appreciate the help.

 

Sure you replaced the correct relays? Some years the f/p relay and the MAF relays were all the same.Move around the relays, or test them, and reset the computer and try again.

Did you reset the computer?
Check fuel pressure?
Check the IAC and TPS?

 

I am sure that I replaced the right relays. The MAF power relay was labeled, and I checked the burn off function by looking at the wires. It wasn't glowing before I changed the sensor, but it is now.

I did reset the computer.


The IAC, TPS and ignition system are next to be checked.

Would fuel pressure really be an issue? The car runs PERFECT at times, and will always run if I keep my foot on the gas. It seemes to me, and I could be wrong, that if it wasn't getting enough gas that I wouldn't be able to keep it running any time I want.

One other issue is system voltage. The car tends to run at about 10.5 volts at idle and a bit less on start up. I have replaced the battery 3 times in 3 years (under warranty), and the alternator is only about 2 years old.

Thanks for any help.

 

Oh, by the way, I am going to a car show this weekend, so I am working really hard on getting this car ready. There are always lots of imports up there with neon lights and big subwoofers who think their cars are fast.

I like to show them what V8 power can do

 

Fuel can be an issue, fuel pumps have been known to start acting up before death. 'New' parts have also been known to be bad as well. Do a tad more digging and see what you turn up.

 

When is the last time you changed your o2 sensor ???

 

[RB] Monkeyspank[/RB]

What in the world would prompt you to lead the discussion to that? Does the computer use the O2 in open loop? To start? Has one ever caused these symptoms upon startup?

One thing I will add here is that if it were a MAF issue, typically, it won't go away if you 'gas through it', it'll still, typically, stall after you take your foot out of it. For the codes, I'd look at the connectorsa and also make sure everythign is bolted up tight for no leaks.

Come to think of it...IIRC actually, someone not too long ago went through the exact same thing... I just can't remember if it was on the TPI board or in gen-tech.

 

Well i was getting code 34 and couldnt find anything then i changed my o2 sensor and never had the code since.

Sorry for my 2 cents i guess he knows every thing. LOL

 

Alright, I have figured it out. Gremlins! jk

Actually, this is getting very frustrating.

I went out this morning and checked over the engine compartment for loose connections, bad grounds, vaccuum leaks, or assorted debris. I also made sure that every cylinder was getting a nice spark.

I checked the TPS. Voltage across AC was 5.02. AB was .42 at idle and 4.6 or so at WOT. I know the .42 is a bit low, but I think it should be close enough for now. Correct me if I am wrong.

Went to a garage and got a free scan with an Auto Xray, and everything seemed normal except it reported .37 for TPS. The guy at the shop seemed to think that the 210 degree coolant temp was out of line and suggested a new coolant temp sensor. I think that 210 on a warm sunny day after a 40 minute drive is reasonable.

Stopped and talked to another mechanic who thought it was the IAC.

Went to a friends house and pulled out the IAC. It was covered in carbon and looked pretty bad. I have a friend at a parts store so I got a deal on a new IAC and replaced it.

The car was running like crap all day. It would stall anytime I came to a stop. With the new IAC, it started, idled, and ran beautifully.

For about an hour anyway.

It is still throwing code 33, idles rough, surges and stalls once in a while.

I don't have access to a fuel pressure gauge.

Sorry about the long message, I just wanted to be clear.

 

I do feel like I have fixed some problems. The MAF burn off relay was definitely not working. The car runs better with the new IAC. The funny thing is that it ran great when the IAC was removed completely even with the huge vaccuum leak.

I am not sure what to check next.

 

Big ole Bump
Hope you clear this up, I am having the exact same issue, only my car is a manual.

 

Red Devil mentioned resetting the computer. How is this done? Should this typically be done after repairing or replacing and electronic part?

 

Is your car doing this even when it is warm? I know my car when it is running warm it Idles really good (except for hesitation) but for the first 3-4 starts it stalls unless I give it gas. Does any one think that it could be a vacuum leak?

 

There is a fuse near the battery. It is in a small weatherproof plastic bracket, connected to the inside of the fender. If you remove the fuse, it resets the computer. Some people say you have to leave the fuse out for 2 minutes or more, but I find that 30 to 45 seconds usually does it.

If you reset the computer, it will clear all stored trouble codes (from when the Service Engine Soon light, or SES, comes on). There is some other information that is cleared when you do this, but there are other people who are more qualified to explain that.

 

If anything, it is worse when the car is warm.

I drove it to work today, and it started and ran great. After about 10 minutes of city driving, it started to stumble, surge, and idle rough. By the end of my 15 minute commute, it was stalling at stoplights. On the way home, it was much cooler outside, and the car never stalled, but the warmer the engine got, the rougher it ran.

 

same issues here, only i can push my clutch in to stop moving. Idling at 2g sucks though! if i tap the gas it will go down to 7-1200 and search....

 

Just hoping someone sheds some troubleshooting light on this subject...