$500 in parts- now have stumbling issue

[evil_twin]

It will diagnose if 1 of your connectors are bad. No, both leads on the coil are NOT positive.

I've had a problem like this before in a vert. There is 1 connector that goes from the coil down where the kick panel is, and it got lose causing the car to have a stumbling problem.

[bimmerboy12]

Hey, do me a favor, and run a test lead from the positive on the battery to the positive on the coil. The battery is right next to the coil correct?

Start the car, connect the test lead, and see if it runs better.

Note: When you turn the key off with the test lead still connected the car will not turn off until you unhook it. LMK what happens. Thanks.

what will this diagnose? aren't both the leads on the coil positive?

[evil_twin]

Hey, do me a favor, and run a test lead from the positive on the battery to the positive on the coil. The battery is right next to the coil correct?

Start the car, connect the test lead, and see if it runs better.

Note: When you turn the key off with the test lead still connected the car will not turn off until you unhook it. LMK what happens. Thanks.

[bimmerboy12]

Not sure if this is an issue w/M20's, but check to make sure you've bled all the air out of the cooling system. It could be your temp sensor isn't getting an accurate reading.

Good point. I will re-bleed and let you all know. Also will check for any leaks with the WD-40 trick.

[BrewCity11]

Not sure if this is an issue w/M20's, but check to make sure you've bled all the air out of the cooling system. It could be your temp sensor isn't getting an accurate reading.

[jlevie]

With the work done on the car it is possible that you disturbed some hose connected to the intake and now have an intake leak. That could explain why the engine runs a bit better with the temp sensor disconnected as that would cause the DME to think that the engine is cold and result in a richer mixture.

[bimmerboy12]

well update for everyone, the problem is not fixed. I verified all connections are good. I am at a complete loss. Any other ideas of what to try???

[bimmerboy12]

did you swap the temp sensor that goes to the ECU or just to the cluster? It is the blue one that goes to the ECU

Yeah swapped the correct one. Never touched the sending unit plug.


I will double check my wires. This doesn't sound like a coil does it?

[abepark]

double check your spark plugs and wires, check that the wires are on tight and all the plugs are tightened to spec. is there any unusually noise near the distributor? sounds like a misfire so check all spark.

[Funkmasta]

did you swap the temp sensor that goes to the ECU or just to the cluster? It is the blue one that goes to the ECU

[bimmerboy12]

put your old one back in...

Swapped my old one back in... made no difference. It idles OK when cold, but after warmed up, definitely stumbles. The stumbling is not even detected by the tach, it just vibrates the shit out of the car, like a random miss. This is getting REALLY F***ing annoying. I tested the CTS and it is good. Remember, it idled fine before beginning this job.

[Funkmasta]

put your old one back in...

[Funkmasta]

coolant temp sensor for sure

[xLibelle]

upon first read of the list you have there, it sounds to me like its the coolant sensor. Swap them back and see what happens.

[bimmerboy12]

Are you 100% sure you've got your plug wires in the right order?

100%. They have the numbers printed right on the wire and cap. I just drove the car to go to the Y, and it was opposite of the problem: the car idled like shit right after it started cold, then got better as it warmed up. Remember, the car ran and idled great before all this work was done...