My 1987 el camino with the c3 carb runs fine when its first started, but after it warms up it drives horribly and has a major shifting problem (right after it shifts it has major lag, almost like it's trying to fall flat on it's face). I know this isn't much info to go off of but any ideas would help. Thanks.

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When's the last time you put a light on that bad boy? Sounds like the timing's off...

How can the timing be off? He has an ECM that is supposed to control the timing.

Check for stored codes and go from there.

Hay! Lets get back to basics.

Is your check engine light on?

If you have no check engine light on, check for a major vaccum leak... :-D

Come on back and let us know what you find?

No, the check engine light isn't on. I'm going to check and see if I have any vacuum leaks this afternoon along with the timing. So for a completely stock 1987 El Camino the timing should be about 4*, or thereabouts, and about 17" vacuum at idle right?

The timing had somehow slipped to approx 2* below 0. I set it back up to 6* and checked the vacuum. It was reading steady at 18". No vacuum leaks and no SES light either. After advancing the timing to 6* I took it for a spin to warm it up and it was much more responsive. However, the shifting was a lot more irradic and when I would come to a stop it would try to disel out and die. Once it was completely warmed up it was running like crap again and tried to die at almost every stop. Any ideas what might be causing such a serious problem without setting off any codes?

Thanks,
Scott

Sounds like carb problems to me. But, before going into that E-carb, I would eliminate everything else. Spark plugs, plug wires, clogged catalytic converter, heat riser valve stuck in closed position, and especially a malfunctioning EGR valve. Check the EGR control solenoid for proper function also because it is controlled by the ECM. If the EGR valve is stuck open, the engine will never idle smoothly, regardless of what else you do (but with 18 in. of vacuum, it is not likely). One-by-one, with the engine running, plug off all the vacuum ports coming out of the carb. If the engine suddenly begins to run right, the last vacuum system that was disconnected is the problem. If you plug the vacuum port to the brake booster, you will have litttle or no brakes, so be careful there. When all else has failed, take a close look at the carb.

How can the timing be off? He has an ECM that is supposed to control the timing.
The timing had somehow slipped to approx 2* below 0. I set it back up to 6* and checked the vacuum. doh!

1) Spark plugs
~4,000 miles on current plugs

2) plug wires
replaced at the same time as plugs

3) clogged catalytic converter
had that checked about 3 months ago - checked out fine

4) heat riser valve stuck in closed position
not sure how this would create the problem I've described beucase the heat riser valve wouldn't cause the engine to run this badly even if it were stuck shut

5) and especially a malfunctioning EGR valve
replaced at the same time as the plugs and plug wires


For some reason the car tried to die the majority of the time when coming to a stop. However, a couple of times it did not try to die at all and idled smoothly. This seems very strange to me and I was wondering if it had anything to do with the torque converter not unlocking when the car is coming to a stop. Could there possibly be something wrong with the Powertrain Control Module that would cause a problem such as the one I'm describing? Or is it the ECM sending incorrect info (due to the carb) to the PCM?

Well, after doing some more reading on the forums here I had a new idea I wanted to run by you guys. I got the idea from this post: Temp Sensor Post (http://www.elcaminocentral.com/modules.php?name=Forums&file=viewtopic&t=1097&highlight=tcc) . Could it be the temperature sensor that's sending inaccurate information to the ECM? Could it be defective and not set off the SES light?

...Could there possibly be something wrong with the Powertrain Control Module that would cause a problem such as the one I'm describing? Or is it the ECM sending incorrect info (due to the carb) to the PCM?
PCM huh? Never heard of one of those in an 87 El Camino before today and I'm pretty sure there isn't one in your Elky. Where did you come up with that theory?

Sounds like either a vacuum leak or maybe it's time to rebuild the carburetor. Either way, you should invest in a good scanner to look at the ECM data.

For some reason the car tried to die the majority of the time when coming to a stop.
That sounds like the TCC solenoid sticking or remaining always energized. If you suspect the TCC solenoid is being energized, just electrically unplug it from the side of the tranny and take it for a test drive. If the solenoid is mechanically stuck, the TCC will lockup as soon as the tranny upshifts into second gear and won't unlock until the tranny downshifts into 1st gear regardless of whether or not the ECM is in closed loop.

I disconnected the TCC Solenoid and the problem went away.

Thanks everyone for all your help!