car will not start when not fully hot but will start fine cold or fully hot

[kickinindian]

so i changed the CPS checked all the fuel stuff. Today i got it to where it would not start, it will crank all day, but will not start.
On a whim I pulled the positive battery cable, put it right back on cranked it and it fired right up without a hiccup! turned it off, cranked it a couple times, started up a couple more times, then again, would not start.
pulled the pos. wire again, and it started right up again. sooo i guess what im asking is what would work fine after its has been reset, the DME? how would i diagnose this?

car: 86' 325es 5spd

[dsphil]

If you have already changed the cps sensor, next is try to replace the main relay. I think that is what my problem was from before.

[kickinindian]

I checked it before and it seemed fine pulled it put it back in started a couple times agian then i shook it and some thing was shaking around in it so im guessing that is it then? But when i jumped the fuel pump relay to test my pumps and they were fine pin 30 and 87 dosent that run through the main relay?

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[dsphil]

Iirc i think main relay has a ground during start and unground when run. Relays can fail intermittently. Replace it and report back

Edit. Check ground connections too.

[kickinindian]

Okay thanks its just wierd that it only does it when its warm and runs fine after after i pull the battery....

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[jlevie]

The first thing you need to do is to determine if this is a fault in the engine management system, or something else. Check to see if there is spark, injector firing, and normal rail pressure when the no start condition occurs.

[kickinindian]

I had spark and fuel most of the time then randomly no fuel. i would before wait 10min or so and my car would start up and purr like nothing happened. now i found if i pull the battery cable the car will start after that. also sometimes after i pull the silver main relay. i could not think of any more things to diagnose. my pumps are both fine and have good pressure when running.

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