Hey guys. First, i want to introduce myself cause i just bought a 5.7 '87 IROC and its my first F-body so I'm new to alot of this. I bought the car with 45k on it so I expect to not have much problems with it, but in the last two mornings i've already encountered something that hopefully some of you can help me with. Early in the morning on my way to work I start the car, let it warm up a bit, and then as I drive down the block it shuts off. I start it back up and it immediatley shuts off again. It's not until the third try that it starts back up and runs fine for the rest of the day. This has already happened twice. Both times about 2 miles into my morning drive to work. Any suggestions?

By the way, I haven't had time to do a whole tune-up on yet. I'll get on it tomorrow.

 

Is this a carb or TBI/TPI??

 

TPI

 

Might be running too rich in open loop, then runs fine once the ECM takes over in closed loop. Could be leaky injectors but try cleaning the IAC first.

 

Well unfortunatley i havent had a chance to clean the IAC but I definetly will this afternoon. But I did do an oil change and cleaned the TB since this car has been sitting for the last 5 months. This morning on my way to work, the same thing happened, the only difference is that this time, it took a few tries to get the engine to turn. Before, I could start the car back up on the second try but this time i was out in the middle of the road for about a minute trying to start it back up. Later during my lunch break, the SES light came on and off a few times.

Could it still be the IAC or leaky injectors?

PS. the last owner didnt drive it for almost half a year and isnt sure when he did the regular maintance procedures. He only told me that the MAF sensor is pretty new and the battery is new. I'm gonna have to get in there and give a hell of tune-up

 

This weekend I got a chance to change the plugs, wires, distributor cap/rotor, o2 sensor, pcv, fuel filter, and clean out the IAC. I took it for a test drive and it seemed fine. Later that afternoon i drove it to the gas station a few blocks from my house and it turned off on me again. Only this time it took about 5 for it to start again.

When the car dies, it doesnt sputter or anything it just shuts off as if I were to turn the ignition off myself. the electrical stuff stay on but the car just dies and i have to roll it to the side of the road (if i'm lucky enough to get there). Sometimes I can get to start right back up. Other times it takes a while. It would only crank but not turn over, and then after a few minutes of trying to start it up, it would.

The other problem that isnt helping this situation is that if its shooting a trouble code, I cant even read it because something must be wrong with my ALDL, it doesnt even shoot code 12. I was wondering that may be this whole issue could be tied with the ALDL failing and be an electrical problem?

 

can anyone help me on this?

 

anyone?? i am also having the same problems with my 89 trans am with a 305 tpi, with 53k miles on it..bought the car about 3 months ago and its doing the same thing Rosadoc-Z has been describing. (i've changed oil and filter, spark plugs, air filter)

 

Well this morning on my way here to work, it got worse than ever before. The car turned off on me about 5 times in the 20 min drive to work. about 2 of the times i could start it back up quickly. The other 3 times it took a couples of tries of it just cranking but not turning. There is no warning signs of it turning off, it just shuts off. Like i said before electricity still works when this happens but i can't tell if there is a SES light because none on those light on my dash work.

I havent had much luck getting responses on this thread buy please someone any help would be appreciated
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oh one more thing i'd like to add. As the car was shutting off this morning, i tried to take notice of anything that was different. The one thing I noticed is that the warning buzzer (the beep you hear when the lights are left on or when you stick the key in the ignition) was not going off. As the car died each time, i tried completely removing the key and putting it back in, none of those times made that thing sound.

 

sounds like it might be something in the dist. Have you checked for spark when cranking and fuel pressure when its hard to start that is where to start. Look for a good spark when cranking when it shuts off.

 

the only problem in doing that is that it seems to ALWAYS happen in the morning on the way to work in the middle of traffic. at this point, i'm just interested in getting that car turned on and on my way to work on time

 

I had the same problem, but mine eventually quit all together and wouldn't start again. My ecm turned out to be bad. Then again, water getting on it probably didn't help at all.

 

well i never had to replace an ECM on any car before. Is it as simple as taking the old one out and plugging the new one in? or is there more to? Also, is it safe to buy a non GM ECM? I'm gonna have to go in there and change alot of stuff because i have no idea what it could be. Trial and error from here on.

 

The ALDL itself doesn't cause failures. Not being able to read the computer from the ALDL may be a good indication of an ECM problem.

Any ECM you get will be GM, it will either be reworked by GM or by someone else. I haven't heard consistent stories of bad non-GM reworks.

Some come with the PROM, others you have to take your existing out and put it in the new ECM. Not a big deal either way. A lot easier than changing the distributor cap.

 

do you think the ECM is also the cause for the car dying? the thing is strange to me is that it only happens in the morning on my way to work. I could have it parked for 8 hours in the afternoon and run it in the evening and it would be fine.

 

I believe the problem is electrical and ignition related. I'm betting that the computer isn't reading the cylinder ID properly and shutting the engine down. Try swapping out the distributer. The RPM sensor is in that.

 

The computer doesn't read the cylinder ID.

 

Isn't there a sync pulse on the reluctor ring? If this is failed to be "read," wouldn't the car stall?

Everyone knows all fuel injection systems must include A throttle body to meter in air, TPS, an rpm sensor, fuel injectors, and an ecm or pcm. Shouldn't the RPm sensor in the distributer tell where the engine is in the rotation cycle? I thought this was read by the ecm. But I could be wrong. Is that what the ESC is for? And if the ECM doesn't read a cylinder ID, how would it know the timing and change it with different engine load AKA changes in LV8?

 

Well I'm getting a little tired of this car shutting off on me every morning. Not one morning since I got (2 weeks now) the car has passed without it dying. In the afternoon and at night the car runs great even in a 2 hour drive i took it on last week. So what is it about the morning that would cause it to die in the middle of traffic (it ranges from 2-5 times of shutting off in the 20 minute morning commute).

PS, it has also died on me while it was idling at a stop sign, so its not just while its driving.

 

Hmm.. I seem to be having some of the same problems on my 87 trans am.
I've changed nearly all the sensors except the Maf and air temp, and the rotor and module. Even the fuel pump, relays and fuses. Maybe I'll look into the Maf and the ECU next. Not a big deal changing them, the car is like 20 years old, it probably needs them.

 

I've replaced the MAF sensor and relay but it didnt help. I'm thinking the ECM is next. But since its ONLY happens in the morning i'm thinking it has nothing to do with the ECM or sensors.

What I'm starting to suspect now is that since in the morning I find alot of condensation on my car from the usual morning dew, there might be moisture in my distributor cap. The only doubt i have is that I wouldnt think a little moisture would make the car shut off, especially 5 times in 20 minutes. Unless its a lot of moisture.

 

IGNITION MODULE

 

well here is an update. Yesterday I decided to check the distributor and wires since I now believe that the reason it shuts off (ONLY in the mornings) is because of the morning condensation. Every morning i leave for work around 7:30 and every morning the car has so much morning dew on it that it looks like it rained the night before and like i've said, every morning the car dies on me a few times on the way to work.

Well last night i opened up the distributor cap and took out the plug wires and coated the boots and all the contacts with dielectric grease. I also removed the wire that goes from the coil to the cap and noticed that the inside of this wires boot was rusty. I dont know why there should be rust in the boot but i sprayed that out with some electric contact cleaner and gave it some dielectric grease.

Fast forward to this morning and for the first time, I made it to work just fine.

I'm hoping this will stay this way but i'm worried that rust is in that wire boot for a reason and i gotta find out a way to prevent it when i buy a new wire. Any suggestions?