Page 1 of 1

Sometimes spark, sometimes not

Posted: Sat Feb 21, 2009 4:38 pm
by 800vtwin
Inconsistant spark during crank. 50% of the time i have spark at crank, fires right up and runs good for as long as i want. Other times just cranks and cranks. I have to stop for a second and recrank two or three times - then spark. Using tach reference, everything looks good. Consistant crank signal (vr with 10k resistor), cam sync on rising edge. When i have no spark, there is no rpm signal. I've datalogged and used tachref a few times but don't see anything unusual.

Any suggestions? I've seen a few posts with the same problem mentioned but no definitive answers.