M4-2000-08

Can't figure this one out, recently engine would just shut off while driving and sometimes but not always would blow 15 amp ecu fuse. Replaced main relay and seemed to fix the issue, but a few days later after shutting off engine to pick up the kids it wouldn't restart. Fuse good, main relay functioning, c.e.l. functioning, but no fuel pump prime. After it sits for at least an hour and a half, the fuel pump will prime and engine will start. Has done this the last 4 days straight regardless of ambient temperature. Seems as it only does this after so many miles, as i stopped at a friends house a few miles from home and it would start, drove the rest of the way home and shut it off and wouldn't start.

I've replace the main relay with a new one, tried a spare ignitor, and a spare ecu. For some reason the fuel pump just won't run until it cools off even with the main relay working.

What am I overlooking here?

Thanks in advance,
Justin

jdowen2

I would suspect the fuel pump or wiring to the fuel pump.

M4-2000-08

I replaced the fuel pump last year.

M4-2000-08

I may stand corrected, with car running normal, I unhooked main relay and jumped the fuel pump wires and the pump ran. When it shut down I tried jumping the wires and it didn't run, but the jumper wire became extremely hot, leading me to believe either the pump is shorting out or has a bad ground. Have to toubleshoot further next time it does this cause the pump started working again at its normal 6:30 pm.

Big question is why does it only do this when its at the warmest part of the day? You can almost set your watch to when it will shut off and restart, almost like its on a timer.

doctorbee

thermal expansion. things get bigger when it gets hotter and an exposed wire that's not a problem in cold weather becomes one in hot weather

M4-2000-08

Makes sense, its cooled off significantly around here and problem disappeared even at the warmest part of the day. Hard to trouble shoot intermittent problems. I've got the interior out on the passenger side waiting for a hot day to make it malfunction again so I can start testing voltage thru the harness at each connector. I hope its a bad wire or connector, I hate to even think about pulling the tank back out of the car, huge p.i.t.a.