More fuel problems?

[johngreenedc]

1992 525i, 160,000, m50, manual

Posted a couple oweeks ago about stumble and stall issues. Replaced fuel filter and fuel pump relay which seemed to cure the problem. The car was running fine until today. This morning doing errands, etc. I was driving street and freeway with no problem until I got below a quarter tank of gas. I felt a slight stumble and couldn't find a gas station in time before the car stalled. It would not start (cranked well but no fuel getting to engine). After AAA put 2.5 gal of gas in the car started and ran well enough to get to a gas station and put in more gas. Car ran fine to home (about 3 miles).

Does this mean the fuel pump is dead? Or failing? Or is there a filter as part of the fuel pump that needs to be cleaned? Or does the pumped need to repostioned? Why does it seem to work fine with a quarter/half tank or more of gas but dies when less?

Help. Any suggestions appreciated.

John

[philbyil]

Have you checked the accuracy of your fuel tank sensor as it might be reading incorrectly. This is quite uncommon but you never know!
There could also be a lot of water/crud in the bottom of your tank. There is a strainer screen on the bottom of the fuel pump but its part of the pump assembly.

[johngreenedc]

Have you checked the accuracy of your fuel tank sensor as it might be reading incorrectly. This is quite uncommon but you never know!
There could also be a lot of water/crud in the bottom of your tank. There is a strainer screen on the bottom of the fuel pump but its part of the pump assembly.

Can you clean the screen? I am confident my gas gauge is accurate. The number of miles I have driven matches the amount of gas used with reference to my mpg (18.2 around town).

[bubba966]

Just because the gas gauge moves a half a tank when you use 10 gallons of gas doesn't mean that the gauge is reading correct if the zero level is wrong.

It sounds like the gauge is reading 1/4 tank when it should read empty.

Try filling it up when you're at a 1/2. If you only get 10 or so gallons in, then the gauge is probably fine. But if you get about 15 gallons in, then the zero point on the gauge is 1/4 tank higher than it should be.

[philbyil]

Bubba's got the idea
And yes, you wud have to remove the fuel pump assembly to access the screen. This would also be a good time to visually check the bottom of the tank as well.

[johngreenedc]

My gas gauge does register very slightly (about 1/2 gallon) higher after I replaced the entire instrument cluster with a 95 (cost $100, time to install 2 innings of an Angel game) a few years ago but a fillup at half empty is right around 10 gallons, qurter tank about 15 gallons.

John

[bubba966]

Looks like it might be time to drop the tank and check for debris that's clogging the pickup on the pump.

[Barney Paull-Edwards]

Ferret did a thread about this problem and it applies to all E34`s,there is an O ring in pipe by pump which goes and bleeds air to system,worse for diesel starting but affects all.Crud in tank does not help, I had both,now starts first touch.

[Barney Paull-Edwards]

Its part number 16141179153.