m42 dies and will not idle, replaced tons of parts

[Clemons]

Hey guys, I am new to the m42 but not bmws. a couple months ago i purchased a 91 318is coupe i drove it home two and a half hours and it ran fine. the next day it broke down with a bad fuel pump, after replacing it with a walbro 255 all was well. after driving it for a few miles it developed this really weird idle issue, unless you hold the gas it dies. it also sounds kinda sketchy around 2k rpms when getting holding. this car does have upgraded coil packs, k&n filter and a turner motorsports tune. (appears that mess under the intake has been taken care of). will do a hell of a doughnut when running.

parts tested: all 4 coils are working, swapped in oem ecu, tried to adjust idle screw on intake, fuel pump is working but does not prime

parts replaced: spark plugs, camshaft sensor, intake boot, fuel pressure regulator, fuel pump, vacuum lines under intake, icv, fuel filter

the battery is dead at the moment since its been sitting i need to charge it and see if i can pull the codes (if there is any). any advise is greatly appreciated.

[roguetoaster]

fuel pump is working but does not prime

By that you mean you don't hear it come on when you key the car to ON, but don't start?

Have you pulled a fuel line to confirm fuel is being delivered? Did you reinstall the vacuum line going from the throttle body to FPR?

[Clemons]

By that you mean you don't hear it come on when you key the car to ON, but don't start?

Have you pulled a fuel line to confirm fuel is being delivered? Did you reinstall the vacuum line going from the throttle body to FPR?

When I turn the key on the pump does not prime, I did disconnect a fuel line that runs to the injectors (even pulled the rail and cleaned the nozzles) it fills a water bottle up in about 15 seconds while trying to start it. That vacuum line is connected. I replaced them since they were in poor condition. The car will start but will die if you let off the gas pedal.

[romeomike]

You'll have to get the car hooked up and running for a bit to get codes (if any). If the battery's dead, whatever codes that might have been there were erased.

I'd look carefully to ensure all your vacuum lines are hooked up. I had one drop on me and until I figured it out I had your symptoms of starting and dying...etc.