Help! ECM Problems

[Peek81]

ECM progress - replaced ECM # 3 it works

Cold start problem - engine starts -choke set - fast idle then it stalls - like a lean condition.unplug distributor ecm harness or coolant sensor and it runs in open loop without the engine stalling.When engine is warm and ecm goes to closed loop it runs great.Problem exists when engine is cold - open loop.

Parts replaced
oxygen sensor,coolant sensor,dist.module,ecm,egr and pvc valve ,new carb.


Any suggestions;help

 

[Peer81]

Hello Peek81,

Welcome
First I was thinking, well somebody hacked my account but there is one letter different.
About your problem, could you give a more detailed discription of what the engine is doing before it dies, could you keep it alive with reving the engine or changing the choke valve (when cold)? The more info we have the better we can help you

Greetings Peter

 

[Peek81]

Hello Peek81,

Welcome
First I was thinking, well somebody hacked my account but there is one letter different.
About your problem, could you give a more detailed discription of what the engine is doing before it dies, could you keep it alive with reving the engine or changing the choke valve (when cold)? The more info we have the better we can help you

Greetings Peter

Unpluging carb. TPS would make it run.I believe ECM was holding it in one rich position?Maybe a faulty ground or connection of wiring harnesses.

 

[Peer81]

Allright just some small idea's..

For the first ECM, no check engine light? Is there 12v to the check engine bulb or not?

For second and original ECM, running rough, start checking if the MC solenoid is working if so what is the dwell output?

At the last resort I would suspect the wiring harness so first check the ground lines.

Groeten Peter

 

[Evolution1980]

Peek81, Welcome to the

I took the liberty of moving your thread to the L81 section. Lots of people in here very familiar with your setup. We'll get ya on the right track and squared away!

 

[Sensei]

The first thing I recommend is to get some Caig Labs "Deoxit" contact cleaner and put it on every connection in the entire CCC system (ECM, Chip, Distributor, Carb, sensors, etc.) You might find this by itself fixes everything, but even if it does not, it is a half hour well spent.

Now, what if that does not fix it? Do you have the original GM Service Manual? If not, you are shooting in the dark. Get the manual and follow the troubleshooting flow charts.

God bless, Sensei