Author Topic: Fuel pump acting up  (Read 3379 times)

B318M42W

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Fuel pump acting up
« on: July 19, 2010, 03:24:42 PM »
is my fuel pump dead again? jumped to battery voltage, it barely pumps, and when engine running seems fine. also, the wires get really hot when powered. Nothing happens (no heating wires) if i disconnect the ground side of the pump, and wires do heat up when connected. this is the 2nd pump that dies in a year.

3 options:
1) got a short somewhere in the wireing
2) pump's dead
3) the pump support is bad.

what you you guys think?
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jscribble

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Fuel pump acting up
« Reply #1 on: July 19, 2010, 05:35:46 PM »
Bad filter or screen on the pickup?
Betty - Sold
Sabine - 2004 325xi

B318M42W

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Fuel pump acting up
« Reply #2 on: July 19, 2010, 09:33:14 PM »
filter was changed at the same time as the fuel tank, about 1 month ago. strainer looked good at that time.

I ordered  a new TRE 255LPH pump. should get it in a few days.  Hope that it's going to fin it and it's going to last a few years! tired of the annual fuel pump renewal!
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jscribble

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Fuel pump acting up
« Reply #3 on: July 19, 2010, 10:12:18 PM »
I would replace the strainer, even if it looks good. There should be no resistance to flow on that end, or the pump will die extremely fast. Other than that, idk. You seem to have your head in the game at least as much as the next guy.

How much did the hipo pump cost?
Betty - Sold
Sabine - 2004 325xi

B318M42W

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Fuel pump acting up
« Reply #4 on: July 20, 2010, 02:24:41 PM »
94$ shipped to canda.

thanks for the thoughts though. i'll check the strainer really closely when i'll replace the pump.
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B318M42W

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Fuel pump acting up
« Reply #5 on: July 28, 2010, 11:24:49 PM »
replaced my fuel pump and it worked fine... for about 1 minute until it blew the fuse. replaced fuse, and this time, not getting any power to the pump.
I jumper wired the fuel pump relay, already have a seperate wire running from the relay to the fuel pump.  

what's the issue this time?!? sounds a lot like a short, but where???!!   bad ground????

oh and it seems intermittant ie: first start of the day is fine, but after a minute or 2 it dies.


any ideas are welcome!
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locknload

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Fuel pump acting up
« Reply #6 on: July 29, 2010, 06:04:25 PM »
Have you checked the wire harness at the pump?  many instances of corrosion/loose molex sleeves on these cars.  Open up the connector on the wire and clean the insides of the connectors and gently re-crimp them so they grip the pins on the pump.

Also, I'd start with a direct wire connection from the + terminal to the pump.  If that works, it's just a process of elimination of the bad wiring sections: Main bus to fuse, fuse to relay, and relay to pump.  If the direct wire doesn't work, it (almost) has to be a bad pump or a bad ground.

Edit: Oh, wait.  Check the bottom of the fuse box and make sure the wires that connect to the fuse are still snapped in place.  This drove me nuts once, one wire had slipped out of its socket and was just floating on the end of the fuse due to the spring property in the wire.  When I'd pull the fuse, the wire would look like it was in place, but it wasn't locked in.
« Last Edit: July 29, 2010, 06:08:22 PM by locknload »

B318M42W

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Fuel pump acting up
« Reply #7 on: July 29, 2010, 08:26:41 PM »
cool thanks for the heads up.  

basicly did all that and turned out to be a loose wire from where I tee'd in my seperate wire last year. all fixed! (well almost...) the TRE pump pulls 10A (called them for that info) and the fused wire didn't like the extra 7.5A and was heating up a lot. left to do: replace fuse socket!
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