engine dies...screen capture included

[borflink]

I'm tuning my latest MS project, and I need a sanity check.

Running MSII V3 board, firmware 2.33, MT v2.25. Controlling fuel and spark on a stock '94 Chevy 350 TBI with small cap HEI.

With the engine warmed and regardless of RPM, engine dies. I grabbed a log file, and screen captured the offending event.

Which direction should I go? Ignition system or fuel system. I see the RPM signal go from ~1000 RPM to 0 RPM. The injector duty cycles follow the RPM event with O2 following that.

I'm swapping the dizzy module tomorrow, and I'll post if that fixes.

Steve

[borflink]

Thanks, I'll try with 5vref signal disconnected tomorrow. I do have a couple "spare" modules to try also. I wonder if an adjustment to R56 would help? is there a tuning proceedure to tweak that POT?

Steve

[borflink]

ok, no joy with 5Vref line lifted from dizzy module. I changed the module and I was amazed the difference. Several annoying processor resets that were happening before, were fixed, along with a better idle, stable rpms at idle, and I could close the IAC more, probably due to hotter spark.

I idled for a good 15 minutes with excusions to 2000 rpm occasionally, which would give the module enough heat to fail.

I realize that there are a bunch of solid state junctions within the module, but this really affected a lot of other things.

Issues that were fixed by changing the 8 pin module:

processor resets accompanied by intermittent accell triggering.

rough, unstable idle with a hit/miss misfire. Probably weak spark.

RPMs would go from ~1000-0-400 or so. this is shown on the first screen capture. Injector duty cycle followed RPM, just like it is suppposed to.

I'm wondering if voltage spikes were being fed to my processor VIA the VREF line?

Hope this helps someone else

Steve