Technical > Triggering

Porsche 944 turbo Less P. Trig Error NEED HELP!


Hey guys,

So recently I got my 1986 Porsche 944 turbo up and running with the VEMS plug n play unit. The car starts and idles beautifully and under acceleration everything seems to work fine. However, as soon as I push the clutch in and attempt to rev the car (whether it be out of gear or shifting between gears; both up and down shifts) I get the Less P. Trig Error and the car retards timing and dumps fuel, not allowing me to rev past 1400RPM.

I've looked through everything on the ecu and cant find anything wrong. I've also gapped my old facet sensor down from factory location until it rubbed on the teeth and it didn't help it. I just purchased a new Bosch sensor and have tried almost every value of gap from touching the teeth on the ring all the way to not reading the sensor at all.

I seem to have been able to find the correct spot where if I push the clutch in when the car is COLD, I can rev it properly and everything works. However, any time the car gets hot it errors over and over again. I've checked the ecu, replaced sensors and checked the gap between them and the teeth, and now I'm out of ideas.

Does anybody know how to fix this or have any other ideas? I'm using a stock clutch and pressure plate mated to a Spec Aluminum flywheel SP44A.

Is there another sensor that is better than the others that I don't know about? Or is there somewhere in the ecu I can change the sensitivity to cope with the problem? Does anybody have the stock primary trigger setting values for an '86 944 turbo somewhere that I can see?

Anything helps guys, I'm starting to go crazy! :o


noise? spikes on the the signals? Resistive sparkplugs?  Got a scope?


--- Quote from: fphil on August 19, 2020, 07:59:31 am ---noise? spikes on the the signals? Resistive sparkplugs?  Got a scope?

--- End quote ---
I have the image of the triggerlog but don't know how to attach images on this forum. If you give me your number or email I can send it to you.

I'm very new to tuning as well as the electronics behind the scenes so sorry if I'm incompetent at times  ;)


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