Who has the random misfire problem?

[LightningGSX]

Whos got it? I have an idea that should fix it.

[StealthGST]

you mean me? Although mine's just fuel problems heh, hoping a good fuel regulator and a tune will fix it

[blageo23]

I got it! I just swaped a 6bolt in and it sucks. whats your idea?
Mike

[LightningGSX]

you mean me? Although mine's just fuel problems heh, hoping a good fuel regulator and a tune will fix it
You didn't have the misfire code when I checked last.

[scheides]

I don't think I do, right now I'm throwing CEL due to all my EGR stuff missing.

[LightningGSX]

I got it! I just swaped a 6bolt in and it sucks. whats your idea?
Mike
Smooth out the crank angle pulses.Like average them out over say 4 pulses.The pulse edges will still be the same, so injectors and timing will trigger as its supposed too, but the ECU won't think there is RPM fluctuations anymore.I'm about 99% sure it will work.

[1ViciousGSX]

Smooth out the crank angle pulses.Like average them out over say 4 pulses.The pulse edges will still be the same, so injectors and timing will trigger as its supposed too, but the ECU won't think there is RPM fluctuations anymore.I'm about 99% sure it will work.WTF? :rolleyes:

[TalonFiero]

I have RM if I unselect the check in DSMLink.

Jim

[LightningGSX]

WTF? :rolleyes:
The ECU times the crank angle pulsewidths for RM checking.If the times change drastically, from pulse to pulse, the misfire code gets set.The injection and ignition get triggered on the falling edge of the pulse(when it goes from on to off).I'm not sure what the actual threshold is, but for example, lets say one pulse is 50 mS, and the next is 40 mS.Since normal accel/deccel can't change that quickly, the ECU interprets that as misfire.Now if you were to smooth out the pulses, like not let them change more than 2-3 mS per pulse/per 4 pulses, by extending the beginning of the pulse so the falling edge stays where its supposed to be, misfire code would be gone and nothing else would be effected.

[LightningGSX]

For the fixing part.I have these tiny self contained data loggers that I built a few years ago.First, I log CA signal fluctuation on a vehicle where the CA sensor is on the crank(my 2g).Second I log CA signal fluctuation on a vehicle where the CA sensor is cam mounted(1g or 2g w/1g motor).From the 2, I can figure out the threshold.After that, the actual smoothing part is real easy, I've thought up about 5 ways to do it, most cheap and reliable.