Intermittent Starting

[Bolt-on]

I am running MS3 Pro on a 24x LS series engine. It has been working very well, except that it sometimes takes a few tries to start. I only crank it for a few seconds. It either starts right away or doesn't start at all. When it doesn't start right away it often backfires out the exhaust. Sometimes it takes three or four tries to start it.

I had it dyno tuned at around 700 hp. The tuner had a second O2 sensor that was reading leaner than the Innovate setup feeding the MS3 by about 1.5 AFR points. Could this be a rich problem? When it starts, it lights right up and runs well.

I have (hopefully) attached a datalog of it starting and not starting, and the tune file.

Any ideas? Thanks!

Edit: I just found that the battery voltage is 11 at rest and about 9 when cranking. I'll try a new battery.

[Bolt-on]

It's not the battery. Any ideas?

[Matt Cramer]

Start by adjusting the cranking pulse width. You may also want to use the cranking taper curve.