Fuel pump help.

[E30SPDFRK]

I just blew the 4th in-tank pump I have put in my car in a 2 weeks. wtf.

The first one was the one that ran perfectly in my car for the first 10,000 I owned it. I had the car sitting over winter while I did the engine swap, then it died a bit after I got the new engine running.

I pumped out all the old fuel thinking that may have been the cause and put a new used one in. I put my old sock on it because it didn't come with one and it died about 30 miles later. When I went to pull the pump out the sock had come off taking a little vane with it. I guess this one is kind of on me, although I did put it on correctly.

I borrowed one from Cory today and that one didn't work at all, so I got another used one and got almost a mile before it too died.

Is there anything I should be checking on the car that could be blowing all of these or could this just be a coincidence? I'm getting 12 volts to the pump, the tank is about 3/4 full. The exterior pump seems to be working fine, fuel filter is less than 1000 miles old.

[Todd Black 88]

If your external pump is still ok, the car should still run fine at lower rpms. If the car is dying, the external pump is cooked as well. I ran for months in my m3 w/o a working intank pump, I just couldn't rev over 5500rpm w/o leaning out.

[E30SPDFRK]

The external pump moves though.

I have been meaning to check the flow but it never runs long enough for me to remember.

[E30SPDFRK]

Any help guys?

[E30SPDFRK]

Nothing? Its bothering me that I cant figure it out.

[jlevie]

I'm a bit confused by references to a sock and external pump. The older system that has an in-tank transfer pump and external high pressure pump, doesn't have a sock. The filter screen is attached to the foot of the transfer pump. And given a 2/3's or more tank of gas the older style systems will allow the engine to run even with a failed transfer pump. The engine might tend to starve out at WOT, but it should otherwise run okay.

What year car is this and how is the pump failing (burned out motor, no pressure, etc)?

[E30SPDFRK]

I was referring to the filter on the bottom as the sock- old habits.

The car is a 86 325e with a m30 swap. The pump stops making pressure. While jumping the relay, the pump never slows down, nothing comes out of the return line, and I can only hear the exterior pump.

[jlevie]

Disconnect the outlet of the in-tank pump, connect a gage to the pump outlet and see what pressure you have with the relay jumpered. Normal pressure from that pump would be about 3psi. Also direct the pump's output into a container and make sure fuel flows well with the relay jumpered. If the transfer pump passed both of those tests it isn't your problem and you need to look at the high pressure pump.

Another check is to pull the level sensor & transfer pump and use a stick to stir the bottom of the tank. If there's a layer of sediment in the bottom of the tank (rust mostly), it can be pulled up on the inlet screen and choke off flow. Rust is quite abrasive and will wear out the fuel pump (and clog the filter) in short order.

[E30SPDFRK]

It is the transfer pump dieing, because it works again for a while when I put a new one in. I think the main pump is the cause of it though, because the car felt kind of sluggish when I was driving it and it has been wining for about 1000 miles. There is no sediment in the bottom of the tank.



What is involved in converting the car to the late model single pump? Would I just be able to put it in and make a new line to go where the old one was under the fender?

[E30SPDFRK]

Bump for my last question

[M3 Ryan]

Bump for my last question

You can convert to a single in-tank pump with new lines for the feed and return setup. This would involve removing the tank, or at least lowering it to run a new line in there. You might as well get a late model tank since they are bigger too (14.5gal instead of 12.5) which would let your M30 drink a little more fuel between fill-ups. Then you could make it into the triple digit mileage on a tank of gas
Seriously though, if you are having that many problems, just swap to a newer tank. I have one here you can have for $10 if you come get it. Has a good pump in it too!

[kronus]

I kept trying to read this thread title as "Want To F.... Want To Fuck? Want To Find? Want To Fail?"

[Jean]

You can convert to a single in-tank pump with new lines for the feed and return setup. This would involve removing the tank, or at least lowering it to run a new line in there. You might as well get a late model tank since they are bigger too (14.5gal instead of 12.5) which would let your M30 drink a little more fuel between fill-ups. Then you could make it into the triple digit mileage on a tank of gas
Seriously though, if you are having that many problems, just swap to a newer tank. I have one here you can have for $10 if you come get it. Has a good pump in it too!

Dude! If I knew you had a spare tank I would be all over that, I paid 10x that for a used one two weeks ago lol.

[E30SPDFRK]

You can convert to a single in-tank pump with new lines for the feed and return setup. This would involve removing the tank, or at least lowering it to run a new line in there. You might as well get a late model tank since they are bigger too (14.5gal instead of 12.5) which would let your M30 drink a little more fuel between fill-ups. Then you could make it into the triple digit mileage on a tank of gas
Seriously though, if you are having that many problems, just swap to a newer tank. I have one here you can have for $10 if you come get it. Has a good pump in it too!

$10 for the tank, $700 for the drive over there :p

Would the new pump plug right into the connector I already have there? Why couldn't I just use the feed and return lines that are already there and just splice a line in where the old exterior pump was?

[E30SPDFRK]

bump