Another Fuel Starvation Thread

[DTFE30]

I did some searching around and it didn't yield any specific results. I have an early model 325e with S50 swap. Last two times at the track I have been having a problem with the car sputtering hard after right turns. They werent long drawn out turns by any means like most people are saying. The car will sputter after I have gotten through the corner and onto the strait. This happens after I have only used about 3.5 gallons of fuel. I have the dual pump setup and I am wondering if the transfer pump could have gone bad. Can the high pressure pump run the car alone? The high pressure pump also is a little noisy. Any feedback would be great!

[E30Gus]

Crossover tube in the fuel tank may be clogged. That was my problem with a nearly full tank.

[jlevie]

It sputtering with that little fuel used sounds like a weak or dead transfer pump. Though a rusty tank is also a possibiltiy.

[BAR51]

Crossover tube in the fuel tank may be clogged. That was my problem with a nearly full tank.

Has anyone found an efficient way to clean out a clogged crossover tube?

[E30Gus]

Has anyone found an efficient way to clean out a clogged crossover tube?

The tube is removeable (if you're lucky) but it is clogged due to all the crud in the tank so the tank needs to be cleaned or replaced.

[DTFE30]

Thanks for the input!

[Wh33lhop]

My car has run with a dead transfer pump for years; I have just had horrible starvation issues when below a half tank. I replaced it the other day and fuel starvation has gotten much better.

I'd check if your transfer pump is operational. Doesn't take that long to access it.

[DTFE30]

Checked last night and it is in fact dead. Just ordered a new one. Thanks!

[Beej '86 325es]

I had my first track day yesterday, and I noticed this problem on my 2/86 build S50 car with 3/8 of a tank remaining.

Where is the cross-over tube located?

Also, I'll check my transfer pump, but if the main external pump is still able to supply the engine under normal conditions, why would it matter if the transfer pump is dead? Maybe I don't understand the 2-pump setup correctly...they both draw through the transfer pump, correct?

[jlevie]

The transfer pump is there to feed the high pressure pump. With the tank mostly full the high pressure pump is able to suck in fuel. But as the tank gets low that work becomes greater than what to pump can do. The transfer pump unloads the input side of the high pressure pump.

[markseven]

Keep the tank more than half-full on non-NASCAR circuits ;)

[Cephas]

Keep the tank more than half-full on non-NASCAR circuits ;)

Easier said than done at 8mpg!

:nice: