MoTeC Global Forum

I have been tuning and working my way through various issues on a dodge viper gen 2 engine that was already fitted with a Motec M800 ecu. These issues are wide and varied from poor power feeds to awful mapping.

It is now 90% sorted but I am struggling to get a clean and consistent start. Occasionally the engine pops or backfires through the inlet or exhaust. It sometimes does this when running too. I have checked all the physical causes, ht leads, plugs, coils, air leaks etc and the fuel/ignition timing seem ok. I suspect noise on the sync sensor.

Please can someone have a look at my ref/sync capture file and tell me if the noise I am getting is acceptable or likely to be causing issues?

Much appreciated.

Kind regards
Nate

Hi,

In the actual triggering voltage range for the signal it looks clean in these captures. There are a couple of small spikes above 4V but these are outside of the trigger range for the sensor.

Hello Stephen.

Thank you for your reply, much appreciated. I am certain there is something wrong with the ignition setup/ ref sync setup as the car backfires/ kicks back on cranking and sometimes spits flames on rapid acceleration. Everything else seems to check out ok. I Have checked the base timing with a timing light so know the CRIP is correct. The number of teeth per crank rotation was set to 20 when I began fault finding this car despite this actually being 10 per crank rotation. The engine ran and was being driven like this despite running poorly, I have checked the odd fire TDC angles are correct and the coil dwell. Do you have any suitable base settings/base map for the 96-02 viper engine to compare to?

Kind regards
Nate

I suggest you verify the IGN expanders are wired to the coils in the correct firing order. With that many cylinders, it's easy to make a mistake, and yet the engine still runs.