My car recently will not function when the temps are cold. The OBD system is not even accessable through the port. When it warms us the car will start, and the computer shows no trouble codes. I tried to warm the ECM and get it to work, but that was not successful. Is there anyone who has experienced this before? It must be a module inside the cab that is malfunctioning when cold. I cannot just start replacing every control module in the car. It will crank, but not fire or have fuel pressure.
I went out this morning (25 deg outside) and no start. I went out just now, ( 55 deg outside) it fires right up. angin, no trouble codes. Smokes the tires off. So there is a very wierd electrical issue at hand here. I am currently trying to read the electrical schematics to follow the wiring order that could keep the ecm from communicating. That could eleminate a few modules.
Does the engine turn over at not fire, does the check engine light turn on with the key on and engine off, if so the main relay that supplies power to the ecm may be at fault. I don't know where it is on your car though, could explain the lack of communication at the diagnostic plug.
My wifes Mazda Tribute will start then die unless you give it gas when its below 40* It does the same thing, when its warm outside, its fine. No trouble codes, nothing.
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Check the power and ground connections at the ECM when its cold and not starting, try wigging the wiring going to the computer.
Check the fuel pump relay ground from the computer, I think you will find it not there when its cold and not starting.
Would not be the first ECM I have seen dead when cold and ok once warmed up.