Author Topic: Hesitation on acceleration! (Read 8585 times)

Ryann · « **Reply #15 on:** November 16, 2011, 12:08:45 AM »

Your FPR is #6.

http://realoem.com/bmw/showparts.do?model=AJ93&mospid=47318&btnr=13_0308&hg=13&fg=15

DesktopDave · « **Reply #16 on:** November 17, 2011, 04:21:17 PM »

When the fuel tank was replaced, did you do any other work? I'm wondering if the hoses are swapped at the tank. The motor can starve for fuel if the supply and return hoses are wrong.

wenbeaver · « **Reply #17 on:** November 17, 2011, 10:29:03 PM »

I tried to hook everything up like it was before i put the new tank in as far as i know. I could have got something screwed up though. Is there a diagram somewhere that shows that stuff? Also i pulled the little hose off the fuel regulator an it didn't seem to make a difference in the idle, also there was no fuel in the line it was just sucking!

Ryann · « **Reply #18 on:** November 18, 2011, 08:33:19 PM »

You should've noticed a slight change in idle speed with the vacuum line removed. I would strap a fuel pressure gauge to your wiper arm and go for a drive.

DesktopDave · « **Reply #19 on:** November 18, 2011, 08:46:56 PM »

There are a few diagrams at RealOEM like this one of the tank. I don't recall which line is which on the pump. If the lines on top of the fuel tank are the only two you re-connected, swap them around & see if it makes a difference.

Up front at the motor, I think the upper one on the fuel manifold is the feed, the lower one is the return. There is also a vac line there running back to the fuel expansion chamber.

wenbeaver · « **Reply #20 on:** November 21, 2011, 05:11:31 PM »

I had to rehook some of the vacuum lines on top of the tank by the fuel pump but there was only two an they were both different sizes, the gas tank is out of a 325 wondering if that would have anything to do with it? There is a line coming out the lower side by the fuel filter that was not on the old gas tank so i just plugged it!??

wenbeaver · « **Reply #21 on:** November 25, 2011, 03:05:21 PM »

There seems to be gas leaking out of the Activated charcoal filter?? So i took it off today an it rusted on the bottom so i think could be part of the problem?!

wenbeaver · « **Reply #22 on:** December 08, 2011, 03:08:49 PM »

K have done some things an it still does not work! I did the "mess under the intake" way to simplify the vaccum lines an replaced everything! put a new charcoal filter on an it still runs the same, as soon as you run it a little bit it hesitates. I also put other injectors in!?? Makes me think its something with fuel. kinda smells like fuel kinda like its gettin flooded out!

DesktopDave · « **Reply #23 on:** December 08, 2011, 04:40:11 PM »

The bottom of that filter should just be for air, right.

Something's not right here. The six-cyl tank comes in two versions from what I recall. One has a transfer pump that pushes fuel from the left to right, then another pump lifts it out of the tank, finally the main fuel pump pushes it through the filter & off to the rail. The FPR then returns it to the tank.

There's also a vapor system that connects an expansion tank to the purge valve, intake manifold and fuel tank.

I'd take a long look at that tank to be sure its doing the correct thing. You might have a suction problem that's starving the car due to vacuum inside the fuel tank. Maybe try running it with the gas cap off?

locknload · « **Reply #24 on:** December 08, 2011, 05:20:51 PM »

Fuel filter-change it

wenbeaver · « **Reply #25 on:** December 08, 2011, 10:53:04 PM »

Put brand new fuel filter on! I also had tried running it with the gas cap off didn't really seem to make a difference, but i am going to check into that it could easily be creating a suction an starving for fuel!