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View Full Version : new problem, grounding issue?


kildea
09-21-2008, 04:14 PM
so i have a new problem, showed up out of nowhere.
v3 board, ms1-extra.
two wierd issues, one is maybe nothing, the other is a real pain in the ass:

1. with ignition on if i unplug the harness cable the vb921s get really hot, really fast.
they are only connected to the ms board at the top of the led resistors, as it's show in the msextra documentation. ground and power (from coils) comes in seperately.

2. all of a sudden i get no rpm when cranking, i had the vr sensor grounded to the correct pin on the harness and working well for a while, nothing all of a sudden.
i find tht if i kind of rub the wire on a chassis ground and hold it there i get a bit of a signal intermittently, then i can rub it around until the signal comes in and it'll start/run ... while i hold it there of course... the best part is that my cable reset issue has returned with this configuration ... so i'm thinking maybe somethin is groundin that shouldn't be, any suggestions?

MrDoug
09-21-2008, 09:09 PM
What kind of coils are you using- Spark out inverted set to yes?

Karl Buchka
09-22-2008, 01:14 AM
Try adjusting the pot for the VR sensor. I have a blind hunch that it'll work.

kildea
09-22-2008, 03:15 PM
karl your 6th sense astounds me :-P

i was working on the car between 3:30 am and 5:30 am when this occurred, i think i must have done some twiddling during that time that has escaped my memory ... most of the night does.
twiddling pots yields signal ... but now with rpm spikes ... dammit!

and the vb921 heting up makes sense now, never mind that bit.