View Single Post
  #108  
Old 09-12-2012, 06:56 PM
drivinfaster's Avatar
drivinfaster drivinfaster is offline
bimmerfest Supporting Member
Location: in the sticks you piney
 
Join Date: Nov 2007
Posts: 10,686
Mein Auto: rescued bmw's
my head hurts from reading all of that...

matt,

there s/b 2 pumps on this thing. 1 in the tank, 1 on the fuel line. the in tank unit is a sending (feeder) pump, while the inline pump is the one that builds the higher pressure.

iirc there are mods to convert to a single pump, but that is neither here nor there. at least not now...

take your fuel pressure readings. if you are not running without the return line being pinched off, then i say fuel delivery is an issue. your pump may be running, but it may not be building enough pressure to allow the vehicle to run properly.

the fpr uses vacuum pressure to reduce the fuel pressure, and when accelerating hard, the vac drops and fuel pressure increases because the diaphram inside closes.

on average, the fuel pressure should increase about 10 psi when the throttle is snapped.

this is how you can check for fpr operation.

so i suggest checking fuel pressure and fuel pump operation. the in tank pump.




df
__________________
Reply With Quote