Cold Mornings will not crank

[magnet56]

I will try that pcm this weekend. It is suppose th be cold enough here all weekend that my problem should be easy to test. As far as burning the starter up, I don't even try to start the vehicle any more until the pump shuts off, and then just a bump of the starter and she fires right up. I've got a CV joint to replace and I guess I will add pulling the cluster out to the list. I will check with a friend of mine about hooking up to his scanner. I appreiciate everyones input.

 

[tripplec]

Ok I have given this some thought and you may have to go back to some fundamentals and start talking to yourself. Yep talk to yourself, I've been caught doing that for some time.

Ask yourself:

Why is the pump running so long when it get cooler?
- not developing pressure over time
- not pump circuilt not disingaging
- can't suck fuel
- etc

What turns off the pump and is it working at this temperater properly?
- pressure switch on injector rail
- computer timed parallel circuit independant of pressure switch for starting only
-

Why would the pump running not let the vehicle fire up? (The pump cycles while runing and therefore cannot have an override. However, there is likely a sensor for oil pressure or a cam position sensor that tell the PCM it is running and turning over but will turn off the pump if it is not running)
- is there spark when it does this
- is the cam sensor working and gapped correctly (if equipped) This is a problem on some Jeeps when they go the vehicle will not start at all.

After a really good discussion with yourself I believe you should be able to narrow this down. Some relays are identical and can be swapped to eliminate an intermitent problem and costs nothing. Trying the other PCM might be an option but I doubt its your problem but give it a go if it doesn't take too long. Have it chilled first.

Good luck.