Megasquirt - Assistance Needed, Very strange problem Options

[yarin]

I drove the car last thursday, ran fairly rough but had some power. Did some tuning, and had this very odd firing problem. I spent some more time today digging into this, here is what i found:

INJ1 bank hooked up to cyl 1 & 4
when either injector connector disconnected rpm goes up
when either spark plug removed no change

INJ2 bank hooked up to cyl 2 & 3
injector disconnect, seriousl drops rpm

Tried both combos. Alternating, 4 and simultaneous 2. reqfuel 9 / 4.5

So my conclusion is that all cylinders are getting spark, but only two are really firing. Furthermore a quick touch of the exhaust port shows that cyl 4 is running much cooler than cyl 3 after idling for a few minutes. I swapped the cyl 3 and 4 injector drivers and noticed an immediate change in head temp. It sounds like the cyl 1 & 4 are getting fuel, but not igniting. When those cylinders no longer receive fuel, the rpm goes up indicating no combustion, but resistance to compress the fuel.

Make any sense to anyone? I attached my .msq file. I double checked my setting, i made sure i'm only running off 1 table. I just took apart my MS box and can't find any obvious shorts, burns, etc. Keep in mind i'm only looking for this problem at 1000-1500rpm. It's not injector related, its driver related. (IMG:style_emoticons/default/sad.gif)

Anyone?

[lapuwali]

I think the one bank thing is if you're running all of your injectors off one driver, which you can certainly do with a four, and a number of people do so. If you're suspecting one driver is bad, try wiring all four up to the one good one, set this option, and run that way. Solves the alternating/batch question, too.

If this is so, then the driver FET may have let the smoke out...

[yarin]

I think the one bank thing is if you're running all of your injectors off one driver, which you can certainly do with a four, and a number of people do so. If you're suspecting one driver is bad, try wiring all four up to the one good one, set this option, and run that way. Solves the alternating/batch question, too.

If this is so, then the driver FET may have let the smoke out...

Can the driver handle 4 low impedence injectors with PWM on one bank? I'll try this tomorrow. (IMG:style_emoticons/default/type.gif)

Dave - I believe spark is OK based on my timing light. I get a consistent equally spaced strobing for each plug wire.

I might bring my MS to work tomorrow and hook up the injector outputs to a scope and see whats going on. Would be neat to capture the PWM waveforms.