M20 Misfire (Please help....)

[iamsam]

have you checked grounds? because they can cause issues like this.

does the check engine light flash at all when it misses?

have you run a compression test?

have not delved into checking grounds too much. Can this really cause a misfire like this?

check engine light does not flash.

Compression test came back ok.

[nando]

have not delved into checking grounds too much. Can this really cause a misfire like this?

check engine light does not flash.

Compression test came back ok.

Yes, all of the engines sensors and the ECU rely on having a good ground signal.

there should be two, one from the oil pan to the frame, another on the passenger strut tower. if it's missing, loose or corroded you have a problem.

[iamsam]

Yes, all of the engines sensors and the ECU rely on having a good ground signal.

there should be two, one from the oil pan to the frame, another on the passenger strut tower. if it's missing, loose or corroded you have a problem.

these grounds will i check.

and thank you so much for your help.

[thereisnoyun]

TPS?

if all else fails try another set of injectors.

[iamsam]

TPS?

if all else fails try another set of injectors.

haven't messed w/ the TPS but from doing some searching it doesn't sound like the TPS would cause this problem. And the injectors we swapped in worked i know because they ran fine in the other M20.

[structured]

Another bump (no homo) because I just had an epiphany. My misfire came shortly after driving my car, which is lowered, through a bumpy ass field. Maybe I knocked that bottom ground out of place. We'll see tomorrow.

[iamsam]

Another bump (no homo) because I just had an epiphany. My misfire came shortly after driving my car, which is lowered, through a bumpy ass field. Maybe I knocked that bottom ground out of place. We'll see tomorrow.

let us know if that was the problem!

[DTMbimmer07]

if you figure out whats wrong with your car let me know, my car is doing the same exact thing, i just blew out the fuel return line today and changed the fuel presure regulator and its still misfiring.

[iamsam]

ok we re-did the engine grounds, replaced the lower one and re-attached the upper one, still missing,

Any more ideas of what it could be??? any help is appreciated!!

[structured]

I was just trying to fix my misfiring issue yesterday. I changed the fpr and tried to clean the distributor cap and rotor, neither of which made a difference. I did, however, notice that the crankshaft vibration damper (or the main drive pulley) is vibrating excessively. So much so that I think that it is making contact with the water pump pulley.

I have a theory that this may be the source of my misfire because the crankshaft position sensor may have been hit or otherwise damaged by the vibrating pulley.

[iamsam]

I was just trying to fix my misfiring issue yesterday. I changed the fpr and tried to clean the distributor cap and rotor, neither of which made a difference. I did, however, notice that the crankshaft vibration damper (or the main drive pulley) is vibrating excessively. So much so that I think that it is making contact with the water pump pulley.

I have a theory that this may be the source of my misfire because the crankshaft position sensor may have been hit or otherwise damaged by the vibrating pulley.

definitely keep this thread updated if the crank position sensor fixes the problem or not.

Sam and I have pretty much decided that the only way to fix his M20 misfire is to replace the M20 with an M50. :D So that may be next.

[DTMbimmer07]

Has one figured out what the problem is?

[iamsam]

Has one figured out what the problem is?

nope, he took his car off the road, and is driving his old Saab again, his E30 is now hos project car, because we can't get it to run right.

[sticksdaman]

Why is it that nobody can figure this problem out? I've been having this issue for nearly 5 months now and still nothing. It's beyond frustrating.

[iamsam]

i think the only solution is that M20s suck. its time for Mr. M50.