1987 Camaro V6 Automatic MPFI
For the past two months my car has given me nothing but one big headache! Lets start with 2 months ago. My car died and would not restart but would crank! Diagnosed it down to electrical spark more specifically. No spark at plug 1 and weak spark from coil that would only spark intermittently. Car has a 120,000 km on it so I figured a tune up was in order. So I changed the plugs, cap, rotor, coil, pickup coil, ignition module, fuel filter, air filters, and pulled the distributor and relubed it. Car then through an error code 42 "est" tracked it down to the new ignition module. Replaced it and car ran great for a half hour. Car then dies and will not start. Error code 42 "est" ignition module again, and then same **** again. Called a performance shop and they suggested a product called bluestreak for the ignition module. So I listened, and replace it . Car ran good for a week!
Now the car warms up and then begins to buck,surge,backfire, and stall, five minutes later all is well and car runs great! Error code 34, figuring Mass airflow sensor ( been faulty twice already ), replaced that and still same problem. Now I replaced the relays, strange now cause half the time the car either bucks,surges,backfires, and stalls or goes into limp mode.
I get the car home after going through all this and rev it up with no SES light on to about 3000rpm for three minutes purrs like a kitten. Idled for ten minutes, then took it out for a ten minute drive and all is well. So the problem is intermittent, spark is great, fuel not a problem.
So if you have gone through the effort of reading this novel please give me any Ideas! I'll try!

 

Make sure the two two-wire plugs going into the coil have a good connect and are vibration-proof (I had this problem). Also make sure the distributor is clamped down real good. I figure from your post you have some experience, but frankly, the hold-down bolt is a real pita (pain in the a$$). Sometimes you think it's tight and its not.

I assume you replaced the wires too? And check all the wires for the EST. Good luck.

 

faulty ECM?

 

I said I will try any suggestions. I appreciate the advice I will try and tighten up the dist hold down bolt. I tried to rotate the dist for I thought that aswell, but she was tight enough that it didn't turn. However it seemed to have a little play holding on to the dist cap and rocking back and forth. By that I mean the dist shaft.
I dont like that but from what I here it is not uncommon. As for the spark plug wires they have not been changed. Should I change them. Like I say the problem seems to be intermittent. If you or anyone can tell me they have ever had or heard of a problem like this caused by spark plug wires I will change them immediately.

As for my experience, I am restoring a 1981 Camaro Z28. It does not have any of these sensors or fuel injection stuff. If it dies it will more than likely be something major! I'm at the point of looking for a new manifold, distributor, and carb for my 87 camaro
and just doing the swap but I want to learn. Ive read these forums for the past month before posting trying to find similar problems that other members have had. So when it comes to EFI I am a rookie and any and all suggestions will help! Thanks for the suggestion!

 

You don't need to replace the wires necessarily. Check the resistance (I don't know the value off hand, but it's on this board somewhere and probably in a Haynes manual). Inspect the wires. If you see obvious marks, this could cause random arcing to ground caused by vibrations or whatnot. I was running on 5 cylinders one day because the wire was too close to the manifold and was grounding out.

As jeremy said, it might be an ECM problem. Don't know a good way of checking this. But if you buy the GM shop manual, usually one of the results of the diagnostic charts is fault ECM. BTW, you should get this GM shop manual because your car throwing a code does not automatically mean replace the sensor. I had a bad MAF relay connection that was throwing code 32 or 34 or whatever it is.

And back to the coil wires, the two two-wire connectors on the coil, jiggle them while the car is running. If the car starts to do funny things, you'll know.

 

Thanks Jeremy for the response. Faulty ECM I hope not. Ive been thinking that aswell. I would think that if that was the problem I would be throwing alot more codes. Is there really anyway for me to check this. Camaro_junkie I'm gonna test those leads at the coil aswell.

On a side note when I pulled the distributor and cleaned it up I dropped it back in and timed the vehicle and got a hell of shock when I rotated it while the car was running. I have never had this happen to me before. Could this means the new cap is faulty or the wires leaking current. I have been zapped too many times in the past but never from timing a car and rotating the distributor.

 

faulty ECM?

 

Well camaro_junkie I think I'll be buying a new set of plug wires tomorrow! If anything they'll give some confidence that they will be good and not the problem. As for the coil I will jiggle it. Need to get a glove so I dont get zapped!

On another side note dont you guys sleep? 1 A.M. here, but hey I appreciate the help no matter what time it is!

By the way I do have a Haynes manual for the car but I find it pretty much useless. Damn near half the stuff in it says consult a GM technician. I need to look for that shop manual! As for the relay for the mass air flow sensor I changed that for I have read that has given many people grief aswell! Once again thanks for the advice. I'll get the new plug wires today and give that a shot!

If I dont post in the next day or two please check back for an update on the situation. My Dad is going in for heart surgery at 7:30 A.M. and I'm sure anyone will understand what my priorities are right now.

 

Check some of these out

 

First, where is here?

Second, Project, I was gonna refer him to your page, but I was too lazy to look it up.

 

If the question is where am I, I'm in Calgary, Alberta Canada.

Second, project thanks for the link. Last time I had a car act this way was the mass airflow sensor ( 87 Camaro ) time before was an EGR valve ( 88 dodge colt ). I didn't think the egr valve was connected in anyway to mass airflow sensor but according to one of the diagrams it is. Hey guys thanks for all the advice. I was at my wits end and now you have given me some great info!

 

Heres the update guys. I blocked off the egr valve and my ses light came on. Code 34 mass airflow sensor. ( its brand new ) so I put the old one back on and no ses light. Took car for a drive and when it was warming up it missed a couple of times at wot. After car was warm she didn't miss a beat. Going to check my timing this afternoon it was set at 12 degrees. Any one have the spec on this car for timing. I have no tags in the engine compartment in this regards. Never the less the car is now driveable and I owe you all a beer. If any of you are in Calgary give me a shout and you can collect.

The car isn't perfect yet but probably about 80 percent better, thanks guys, I just gotta tune out that miss when warming up and I'll be a happy camper.