M42 Noid Light

[Dice_980]

Hello all ive been having a no start engine problem. Did a noid light test and all light up except the 3rd doesn't light up. I had taken it to a mechanic a week ago and they tested out a different DME and that didn't work out what else should i be looking for?

[colin86325]

When the other ECU was installed, did you perform a noid test?  If so, did all 4 light up ok?

The problem might be in the wiring terminal, or in the wiring itself.

[Dice_980]

Thinking maybe the noid light kit wasn't all that good.
Tested the injectors into a bucket while still connected and cranking the engine over all of them squirted out fuel fine.
Fuel psi is 50.
I have tried 3 different DME's to see if they did any difference, nothing.
There is spark coming out of each cylinder.
Compression comes out to be a consistent 180 across.

[steel330i]

Dice, how did you test the injector pressure? Thanks.

[Dice_980]

The pressure was tested through the fuel feed line right before the fuel rail.

[DesktopDave]

50 psi seems a bit high. Bentley specs between 40 & 46psi. When you're running that test, disconnect the vac line from the FPR and make sure pressure rises slightly. If the idle doesn't rise from pulling the vac line, suspect the FPR had failed. Also be sure the FPR line has no leaks.

Then turn the motor off but leave the gauge connected. Residual pressure shouldn't drop off much more than about 10psi an hour or so later.

I'd also do a flow test and jump the fuel pump relay with a jumper in the socket. IIRC our pumps spec out about 100lph, so I'd expect almost 1/2 gal/minute.

Vac leaks are one  of the big failings of the M42...triple-check all those hoses. Better yet, consider eliminating the TB heater plumbing. It's a rat's nest under there!