I have an obd1 P72 ecu. When the ecu is cold it will not allow my car to idle or run. It will allow it to start then cut it off. Why, what would cause this? It is not like their are any moving parts, temp should not affect it (it is not even that cold, only like 40-50, that when it starts the colder it is the worse it is). What can i do to fix it????? Should i put my old cx ecu in, would it even fit?

Please, Please help!
Thank you,
Matt

P.S. If it is avrg, warm, or hot, the car runs totaly perfect.

 

What makes you think the ECU is the problem? What makes you think it's not somthing mechanical casuing it to die? Just curious. ECU should run regardless of temperature (assuming we're not talking excessivley extreme temps)

 

It is starting then cutting off. There are only three sensors that control fuel...
intake manifold temp. sensor ( i have changed)
coolent temp sensor (i have a new one but don't think it is it)
o2(not it, unplug it to test, car still did not start)

Once it heats ( it will take 15-30 min to starting depending on how cold it is) up it will start. The temp out side is only low 50's so gas is not freezing.

It is getting spark and fuel. those are not the problems.

 

did you bypass the coolant line on your throttle body? if so then your throttle body plate is frozen and sticking.

 

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Thank you to everyone who tired to help me. I have finally figured it out! Out of the 5 or 6 times I have posted this and the tones of responces nobody has been right.

It was the temp of the ECU. I took it(the ecu) into work with me today came out tonight put it back in the car (warm ECU in hand) and it started right up!!!!!!!

For some reason if the ecu is colder then 50 degrees(aprox) it will not start.
This is been a wierd thing. I am so happy I have FINALLY GOT IT FIGURED OUT!!!!


I hope the guy from CA reads this, he had the same problem.