Hi All - got a problem I can’t seem to solve.
Car was running after correcting some fuel system issues.
Car is an '86 with a single pump tank and a Walbro 255 lph pump adapted to an '86 in tank pump frame. The external pump was deleted when car was built. It’s been running this way since I built the car.
Due to a leak at the fuel sender seal on top of the pump frame plate(only 3 studs present) I swapped the Walbro to a 1991 318i pump frame & adapted to the smaller size hose outlet. Due to my older tank style, I require a pump frame with a return tube on it.
Electrically, there is a difference in the grounding method of the pump.
The original '86 pump frame assy had no ground wire going directly to the pump. Rather, an indirect ground was created by a tab soldered to the top of the frame plate from the ground tab of the connector and the ground wire was soldered to the return tube of the pump frame. When the pump is installed the tank tabs interlock with the pump frame plate and complete the ground.
The '91 pump frame assy has a ground wire going directly from the connector to the pump.
I really don’t see that it makes a difference.
The pump runs when I straight wire it. I checked the voltage at the pump leads while cranking and got good voltage.
I’ve pulled the #1 plug and confirmed spark - a nice hot white one.
I’ve pulled the feeder hose from the fuel rail and it had fuel.
No matter how much you crank, the car won’t start now.
I got hold of a Bentley manual and performed all the tests on table m(page 49). Everything checked out to be well.
Checked all injectors individually. Even swapped between pins 16 & 17. Injectors clicked when they were supposed to. Injectors are brand new remans that the engine ran on before the fuel pump update.
Main relay clicks per Table m test. Fuel pump runs per Table m test.
I squirted ether into the air box and it ran enough to burn up the ether, then promptly died.
What am I missing?
TIA,
Butler