Trans Am V8 won't start after some troubles

[andersal]

Hi,

earlier this year I made some fault analysis on my MS1 2.2 with the latest MsnS Extra firmware.
Thanks to this board I managed to fix a problem with the MOSFET driver and the injectors started pulsating again instead of being open all the time, this has been verified with the help of a NOID light.

However, car won't start - sometimes it cranks and get a fire or two but never goes into running state.

I have upgraded from 430 cc injcetors to 1600 injectors as well as filled the tank with gas instead of E85 which I was running on before.

Reason for the large injectors is that engine is built for turbo's and usually should run on E85, but as part of the earlier fault analysis I chose to fill it with gas again.

I've attached a logfile of the latest crank. I turned down cranking to 2 ms instead of 4 ms (4 ms flooded the engine), not to mention when I had even larger numbers (flooded).

Battery is fresh and charged. I'm not steering ignition, only fuel.
I've verified ginition by pouring gas directly into the plenum - started for 2 seconds without misfire.

During this last starting attempt, AFR was at 14.7 which is probably a tad lean for starting, but with 4 ms cranking pulse it was around 12.0-12.5 and went down to 10.0 at the time of flooding.

I know 1600 cc injectors are large, but my V8 is on 5.8 liters, twin turbo and supposed to be running on E85 - it will require a lot of fuel.
I managed to max, 100% duty cycle on the 430 cc ones before even reaching engines full potential, hence the reason for the switch.

I have the Flyback board as well with these low impedance injectors.

Please, I need some help with this problem - I've read all there is on the subject.

[Matt Cramer]

The AFR reading is generally inaccurate enough during starting as to be useless. I'd adjust the cranking pulse width by checking the spark plugs after an unsuccessful start. If they're wet, decrease the pulse width; if they'r dry, increase it.

[andersal]

Problem for this was found. One of the new injectors was stuck open so I replaced it and now the car can be started without being flooded. However it doesn't continue to run after starting. I've opened up a new thread for that problem.

Thanks for the reply Matt.

/Anders