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

Put Microsquirt in Injector test mode and you can hear them fire. engine will start and run on the test fires. Microsquirt is getting a strong tach signal and all sensors are reading accurately. Cannot get the engine to start normally. Almost like the injectors are priming and then not firing. Gone through all the settings can not find anything suspect. The most I can get the engine to do is fire acouple times then die.

Annoying part is that I had the engine running and starting smooth just a couple days ago. I did increase priming pulses and cranking pulses. However, the engine is definitely NOT getting fuel.

c-i,

You may have the PWM parameters set incorrectly. See: http://www.megamanual.com/mt28.htm#sn But your fuel pump may be plugged, or there could be other issues.

In any case, you'll get more informed help if you tell us what code version you are running, and post an MSQ file (i.e. your settings) AND a datalog.

Lance.

Got the engine to start and run. I'm getting high duty cycles underload and very lean readings on the AFR. then the engine bogs.

okay i got it to run and did some datalogging and I attached the MSL. Setup is a 440 twin cylinder snowmobile with oil injection. 2x 51 lb/hr injectors with 2.5 bar regulator so they are now rated at 46 lb/hr. running all gm sensors. and LC-1 wide band.

Here is the MSQ.

c-i,

high duty cycles underload and very lean readings on the AFR

Sounds like it's flooded; the misfires pump unburned oxygen into the exhaust making the sensor read lean. However, it may instead be that there's a leak in the exhaust causing the sensor to read lean, and the EGO feedback loop is richening the mix to try to compensate. If this was mine, I would make sure EGO feedback was disabled until you sort it out.

Lance.

the exhaust is in excellent condition, While doing the microsquirt install I went through every nut and bolt on the sled. This includes getting the exhaust re-conditioned including the ceramic coating.

I have tried dis-abling the EGO correction, with little luck. Do you think I should go through my AFR tables and slowly lean them out???

Another thought I had was that my injectors don't have enough time to inject the required fuel. Max 8500 rpm with 2 squirts per rev. = 283 injection events per second. Thinking about trying alternating pulses for the injectors. See attached video of a data logging session.

http://www.youtube.com/watch?v=wqO_wIcq ... e=youtu.be

Just a thought, but have you considered those injectors may be too large - 440cc twin with two 46lb injectors seems overkill and could make it challenging to gain your minimum 2ms fuel as recomended in . As well, running those @ 2.5bar (or 36.26psi) may be a bit low for best atomization?
Lorne

I've got a 3 bar regulator that I will be switching to as my running problem wasn't overfuelling......it was under fueling. Its surprising how much fuel this motor is drinking. I continued to slowly lean out and keep an eye on the spark plugs etc, with no improvement and growing frustration. Yesterday I was getting frustrated with the lack of improvement and loaded a tune from last winter (MUCH RICHER) and the sled ran much better.

I continued increasing the fuel, and this is where I am at (see youtube video). Almost seems that I can't get enough fuel with these injectors to sustain WOT. Duty cycles are much too high and I can't sustain a cruise at high throttle motor dies out. Seems like I can't deliver enough fuel in the given time, for 8500rpm with these injectors. So my equation governing injector size has become time to inject fuel at WOT and not horsepower.....Thoughts?

p.s. currently re-reading injector selection.

Rich mapping:
http://www.youtube.com/watch?v=QRFt63cb ... e=youtu.be

I just calculated my PW from (PW = REQ_FUEL * VE * MAP * E + accel + Injector_open_time) and this is what I come up with using 85 lb/hr injectors.

REQ_FUEL= 1.7 (calculated using tunerstudio)
VE= 70% (from VE table)
lowest MAP reading I aquired from the MSQ's and it's 77.6 KPA.

PW = (1.7 * 0.7 * 0.776) +1msec = 1.92msec

The same calculation with 75 lb/hr injectors is 2.03msec