Question on BMW 3-Series E36 Fuel Pump

I have a 1999 BMW 3231 Sedan that recently acted like it ran out of gas. If I let it sit for a while it will run and start normal for about 5 to 8 seconds, then dies out. I replace the fuel filter thinking it may be clogged. While I had the fuel line disconected I turned the key and got a quick stream of gas...then nothing. Still does the same thing after replacing the fuel filter. Was going to change the fuel pump next.....any other suggestions?

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This post was auto-generated based upon a question asked on our tech article page here: Pelican Technical Article: BMW 3-Series E36 Fuel Pump Replacement

[Wayne 962]

Sounds like it might be the fuel pump or a clog in the lines. See if you can hotwire 12V directly to the pump and run it while measuring fuel pressure. That might give you an indication as to whether the problem is in the pump (or it might be some type of clog in the lines).

- Wayne

[bostogrun]

A clogged fuel line or filter would not be intermittent.

A failing relay or fuel motor could be intermittent.

A relay is a switch that open another switch. See if you can jump the relay and run the engine off the the jumper wire.

How may miles do you have on this car? Fuel pumps are good for 150 to 160K after that it's borrowed time.

[Manolito]

When you turn on the key with an open line, you should get only a quick stream of gas. The fuel pump should spin up to pressurize the system and then stop. The reason is a safety circuit built in to all cars with electric fuel pumps that won't let the fuel pump empty the tank out on the ground after a collision when the engine is stopped with the key still on.

This is not to say that you don't have a fuel pump problem, but what you are seeing is normal.

I am too lazy to look it up, does a '99 323 have a split fuel tank with part of the tank on either side of the spare? How much fuel is in the tank? If it has a split tank and the gauge shows about a quarter tank, fill it up. If the problem goes away until you are down to a quarter tank again, it is the transfer pump.

If filling the tank helps but the problem does not recur, it may mean that you have one of the early jet pump style transfer pumps and the fuel filter was blocked enough that there was not enough fuel recirculating to make the jet pump work. With a fresh fuel filter you may have no further problems.