What is a Fuel Pump Relay?

What does it do? I'm not an electrician or car expert, so just need a simple description of it.

Thanks!

Reply to
Jenn Chang
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I'm not exactly sure, but it probably protects and/or directs the circuitry that goes to the fuel pump. I believe mine is working intermittenly. The car runs fine when it works and dies when it doesn't.

Reply to
Rojo2G

The fuel pump relay supplies the main fuel pump with electrical power all the time the engine is running.

If the engine stalled the supply to the fuel pump would be cut some 2 to 3 seconds later. Fuel after the main fuel pump is at a high pressure, and really ought not be sprayed around too much in the event of a crash.

Steve

Reply to
Steve Rodgers

It's an electrically actuated switch, which lets you use a lower power circuit (from the ignition switch) to control power to a high current device, like a fuel pump. They come in a variety of shapes, depending upon what year your car is. In the case of my '72 145, it's a galvanized metal box mounted on the right side of the engine compartment.

You're welcome.

Gary

Reply to
Gary Heston

The fuel pump relay on my 240 series lives on the drivers side footwell area. It's job is to turn the fuel pump on when it is supposed to be on, e.g. when the engine is running or trying to run and to not spray fuel all over the place if the engine is not running, for example in an accident. This is done with some eltrical contacts and magnetic coils. Sometimes the solder joins fail and relays don't work very well or at all. Sometimes they work when you tap them a little. You can bypass your relay by jumping (on a 240) fues number 5 and 7 I THINK--check this with a google search first, or just check to see what fuse 5 and 7 does. No starts in volvos can be either of the two fuel pumps or the relays, this is an easy one to check with a jumper and a test light.

Reply to
John Roden

Thanks for all your help. Mine was replaced on a 740 and the mechanic just left the failed old relay for my reference. It's just a small rectangular box which says "Made in Germany". Hope the new one works well and won't stall my car...

I have another question later on regarding another part that was added on last time my car stalled. Didn't get a chance to ask my mechanic, but I think you guys will have a better description anyway. Will post the question as soon as I find my invoice.

Jenn Chang wrote in news:Xns946D68EE63424jenn@24.69.255.211:

Reply to
Jenn Chang

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