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Dwell spike and tach signal goes to zero
Posted: Wed Sep 09, 2015 7:29 am
by tx1572
I am having problems with what acts like a controller reset but when I check the log it doesn't appear that is the case. I'm running an MSII on a chevy v8 with a small cap HEI triggering through the opto-in circuit, and I'm still running the B&G code V2.88. It started doing it earlier this year, but then it stopped for a while, but started again yesterday. This log is from when I left work yesterday after it had been sitting all day. Hopefully someone here has seen this before.
Thanks
Re: Dwell spike and tach signal goes to zero
Posted: Wed Sep 09, 2015 7:52 am
by trakkies
Either you have a fault with the dizzy or the opto input or the wiring between, I'd guess. Does it obviously misfire? Does it also happen when cold?
If only when hot, I'd guess at the dizzy. Also if there is a very definite misfire - a lack of spark would cause that while the lack of tach to MS more gentle.
If you suspect the MS, I'd look at the opto input carefully for dry joints.
Re: Dwell spike and tach signal goes to zero
Posted: Wed Sep 09, 2015 1:28 pm
by tx1572
It only acts up when the engine is cold, normally after driving for a few minutes it stops. The truck is a manual and it feels like the engine has shut off and then comes back to life. The tach will almost make it to zero then it starts back up. It's like the controller thinks the engine has stopped turning and cuts off the spark and fuel.