MicroSquirt.com read only forum (Jan.15,2018)

Megasquirt II V.3.0, Porsche 914 2.0. Fuel only, stock distributor, pertronix ignitor driving stock coil, no extra resistors, no R57, no pullup resistor. Stock 2.0 injectors, low impedence using PWM.

I got the car started, it idled like crap but held on. I ran though about 5-6 10 seconds runs with the car idling, probably at around 2k rpm. Its running pig rich, blowing gas out the exhaust. This is why I didnt leave the engine running for too long. I know some of the settings must be WAY off. Maybe its from cranking. My wideband read full rich. I heard stumbling and popping out the exhaust. The exhaust was literally blowing gas all over. This oil is definitely not going to see any road time, maybe a few more runs to get idle ok then its getting dumped. I bet a decent amount of gas snuck by the rings. Anyway.. onto my major issues:

I attached my log files.

*RPM looks pretty valid, no major spikes. It holds around 1700-1800RPM. This is with the Fidle valve open but blocked off.
*MAP didn't drop below 65, perhaps i have a bad leak somewhere?
*ignore AFR, i know its full rich. some runs the sensor didnt have time to heat up.
*How can I be certain the injectors arent stuck open? It's a 4CYL horizontally opposed engine, MS has two injector banks, which bank goes to which cylinders?
*Someone please double check my setting and make sure i'm on the right road here.
*I noticed that when i turn the key to the on position the fuel pump runs but then dies after a few seconds. the relay board kills power to the pump which is also tied to my coil power. is this normal?
*I setup my required fuel to 10ms after seeing it run pig rich, 2L engine, injectors at 24lb/hr, 4, 4, alternating, even fire. the injectors are rated for about 24lb/hr at 3bar. i'm running them at 2bar.
*my injector characteristics are set to 1.1ms open time, 0.10 ms/v compensation, 78% PWM current limit, 1.1ms PWM time threshold, 66us injector PWM period.

If there is any more info that i'm missing please ask and i'll do my best to help you guys help me.

This project is really friggin awesome! I can't wait to get this thing tuned right and running. Thanks in advance!

Screen shot of constants:
http://coewww.rutgers.edu/~yarin/914ms/settings.jpg
http://coewww.rutgers.edu/~yarin/914ms/ve-afr.jpg
http://coewww.rutgers.edu/~yarin/914ms/warmup.jpg

hmm. ok yikes... PWM should have been set for ~30% not 78%. i'm glad i didnt run the car extensively. i'll change this tomorrow and try again. this would explain why i got tons of gas at idle, especially considering the nature of 2.0 injectors flowing too much already.

The fuel pump should cycle on power on. This primes the system. Seem like your injectors are stuck open. I'd hook up a LED to the injector outputs to see what is really happening. Don't pull an injector. This could start a costly fire. Just pull the plugs to them all and hook up a light. That's all I got for ya. I just got my engine started yesterday. Good luck.

A.J.

Ran it some more today. Got some decent data today, not running nearly as rich. This time ran it till it warm up enrichment shut off. Here is a data log graph, all the signals look clean. i'm impressed! damn thing idles at 2500rpm though. Still really rich, i'll tune some more sunday after i change the oil that stinks of gas

Yeah it took lots of messing around with my idle control settings to get it figured out. But now I sit at about 1000 RPM nicely. I actually got to drive it a bit today!

bluetrepidation wrote:Yeah it took lots of messing around with my idle control settings to get it figured out. But now I sit at about 1000 RPM nicely. I actually got to drive it a bit today!

Exactly what variables control your idle RPM. Where do I start? Obviously if i overly richen idle it will drop. Yesterday i was at 2500rpm. i dont have spark control yet, any ideas? Throttle plate is fully closed, no leak to my knowledge. MAP is around 30s.

What type of idle control do you have? I'm guessing a stepper idle valve?

bluetrepidation wrote:What type of idle control do you have? I'm guessing a stepper idle valve?

Fast Idle solenoid which is presently capped off anyway. Thing still idles at 2500rpm with all known holes plugged.

Check your throttle blade to bore, sounds like it's pulling ALOT of air to idle that quick which a small vacuum leak wouldn't do.

Is there an idle screw on the throttle body or a hole(s) in the butterfly?

krisr wrote:Check your throttle blade to bore, sounds like it's pulling ALOT of air to idle that quick which a small vacuum leak wouldn't do.

Is there an idle screw on the throttle body or a hole(s) in the butterfly?

Throttle plate to bore is ok. There are two holes in the plate from the factory, I might have to plug those up. There is a idle air bypass screw, its set to zilch.

Power brakes? PCV? anything that draws on manifold vacuum i'd remove and plug until you can find the culprit. What's your timing advance like at idle and it's been setup with the trigger offset wizard etc?