E30 Fuel Starvation

[williamg]

I'm looking to solve the fuel starvation issue in my E30. The engine starts to cut out in right handers but runs flawlessly on straights and left handers. I started to experience this after about 3 laps into my race session even though I started off with a full tank. I have an 89 E30 which utilizes the stock fuel tank with a single in-tank fuel pump. I have just replaced the fuel pump, but have not track tested it yet. Any other suggestions??? Also what is the sending unit looking thingy mounted in the tank on the drivers side, I was under the impression that the fuel level sending unit was the unit mounted through the fuel pump,whats the second one for, can someone clarify?? Thanks for your help.

[mlytle]

driver's side is a fuel level sender too. there are two, one on each side. the gauge averages the readings.

with new pump and full tank you shouldn't be getting that power loss. does it do it in every right hander? almost sound like an electrical problem where something is disconnecting.

[williamg]

The car would cut out only on right handers, it would run OK at about 3/4 throttle but anything more and it would cut out. I have since installed a new fuel pump but I have not had the chance to test it on the track. Any thoughts as to which loose connections could cause this problem.

[mkehler]

Ireland Engineering sells a fuel accumulator for e30's to solve this..I think they sell it for $50 or something like that, although I believe it requires 2pump e30 fuel system... Either way, I'd call Jeff or Jeremy and ask them, I'm sure they'll be able to help you in some way.

www.bmw2002.com

Matt

[mlytle]

wait, did you say you installed a new fuel pump and have not tried it yet? that should fix it. double check all the cross tank fuel lines and the return line to make sure they are connected.

can you see/smell any fuel spilling from the front left side of the tank under the car? there is a metal line that goes from one side of the tank to the other. they rust out. you can't see it unless you drop the tank as it is on the top front of the tank.

accumulator won't really help if your fuel tank is nearly full. i used to run my e30 race car down to 1/4 tank with just the stock pump in a stock tank. no dual pump, no accumulator, no problems.

[williamg]

That is correct, I have not tested the new pump, but why would the old one only fail in right hand turns yet work properly in left handers and straightaways????? Where exactly are rhe crossover tubes that allow fuel to transfer from the left hump of the tank to right hump??? I would think they would be at or near the bottom of the tank, but I can't seem to find them. Thanks again

[mlytle]

i was getting the same symptoms on my car. changed the pump, all fixed. the pumps can get clogged and also have the pick up disconnect. pump still runs, but doesn't get enough fuel pressure.

there is a soft line on the top of the tank between the two tank covers and the hard line is welded to the top along the front of the tank. it's location caused it to rust through. seen this on two cars. if either of these crossovers isn't working, the fuel won't transfer correctly from the left side to the right. on hard turns to the right this will cause starvation even if the tank is fairly full. if all these stock systems are working correctly, you can run the tank pretty darn low and still have the fuel pressure be fine.

[Bruce Shafer]

Don't forget to check all the rubber on the intake side of the engine for cracks. The 90 degree rubber elbow and any of the other rubber pieces can crack and open up under certain circumstances (such as a right hand turn). This will cause a lean condition and it will appear to be fuel starvation. At any rate it is an easy check. Good luck!

[mlytle]

excellent point bruce.