A few days ago I changed the fuel pump on my 89 TA 305 tpi and this morning the battery was dead, which has been an ongoing problem for the last several weeks. When I tried to crank it over this morning, the fuel pump continued to run for about 45 seconds after I turned the key to the off position. After a few minutes I tried starting it again but the batter was just too low, so I turned it off and pulled the key out and as I was getting out of the car the fuel pump came on again and ran for about 45 seconds. Is this normal?

The old fuel pump was much quieter so I probly never noticed if it was running with the car off, but now I'm starting to think that this could be whats causing the battery to go dead, and possibly what caused the old fuel pump to die, especially if it's turning on at random times during the day and running for who knows how long.

I was thinking that it's probly a bad FP relay, or possibly that low battery voltage could cause a relay to behave like this. It's not a very good battery anyway and it's -5* outside. Or maybe this is just normal

Any Ideas? I was told that the relay is on the drivers side somewhere around the brake booster, but i'm not sure which one it is.

oh, and the ECM is out of a 91 camaro or firebird I believe. I changed it over to a speed density system last year...if that makes any difference at all.

Thanks!

 

There are 2 ciruit paths to the fuel pump: through the relay (under ECM control) and through the oil pressure sending unit (the backup in case the relay fails). Might want to first narrow it down to which one is lighting it off randomly. Unplug one, see if it still happens. Unplug the other, see if it still happens.

Can't imagine why or how it would run for 45 seconds after shut down, and certainly no reason I can think of that would cause it to start back up again randomly, if it was working properly.