Misfire Help

[CAMILOSI]

Check out guys, my 91 lx got a wicked misfire at idle that nobody here at work have been able to figure out.I got a dead cyl #1. Upon checking compression it check good at 150psi, also check the others and they all check out good.

I replace cap,rotor,plug wires and spark plugs with nothing else that oem parts,then went in a dizzy,nest thing I did was shim the egr valve,adjusted valves just in case,swap injectors and nothing else seems to work. Right now I'm out of ideas.Any help will be appreciated.

Also car runs fine after 2k rpms,but below it idles like crap,and when driving u really can't tell it's got a problem.PLEASE HELP!!!!!!

[CAMILOSI]

Also I tired an o2 sensor I had laying around but that didn't work.

Any idea guys?

[MR.PHIL]

did you jump the ecu to see if you were getting any codes?

[CAMILOSI]

Yeah I check but didn't have one.

[MR.PHIL]

did you say you tried a new distributor?

[CAMILOSI]

Yeah I did and it's a brand new oem honda dizzy.Good thing it didn't came off my pocket.Lol.

[WiKKeDV16]

Tried swapping ecus?

Check grounds..(especially thermostat ground..pesky lil sob)

Sounds like ur problem is voltage related...seeing as how past 2k the problem clears up..

Have ur alternator checked out..even if it isn't throwing the batt light on..

Tps voltage(doubt it but worth a shot)

[CAMILOSI]

I'll take a look at the ground and c, worth the shot like u said. I ask about the ecu but the guys at work said that if it was the ecu it would affect all cyl,idk.

[h22-accord]

when i had my stock engine it did happen to me the timing was a little off

[batever]

I'm out of my league on this topic but just off the top of my head free associating I come up with the IACV. Though why it would affect only (or apparently only) cyl 1 doesn't make sense I guess.

Maybe you have an accidental ground or/carbon track somewhere in the distributor that is grounding out the spark to only spark plug one before it leaves the distributor. 20000 volts has a way of finding a way to ground when you don't want it to sometimes.

have you checked the #1 spark plug for spark? If you have using a simple method like a screwdriver on the valve cover, might want to try it with a voltage calibrated spark plug tester as well.

As to the prob disappearing over 2000rpms (in other words, cyl 1 starts firing at engine speeds over 2000 rpms), that is possible, but it's also possible that over 2000 rpms the cyl is still misfiring but the crankshaft is rotating fast enough that even though cyl 1 is not firing it isn't noticeable due to the speed of the crankshaft smoothing out any roughness from the firing discrepancy. Whereas at lower rpms the missing cyl 1 will cause a much more noticeable roughness.

Also I would suggest verifying the ignition timing with a timing light. It's worth doing to eliminate it as a potential cause or contributor.

[wed3k]

it could be something mechanical like carbon stuck between the valves but that would also yield a low compression reading.

[CAMILOSI]

I'm out of my league on this topic but just off the top of my head free associating I come up with the IACV. Though why it would affect only (or apparently only) cyl 1 doesn't make sense I guess.

Maybe you have an accidental ground or/carbon track somewhere in the distributor that is grounding out the spark to only spark plug one before it leaves the distributor. 20000 volts has a way of finding a way to ground when you don't want it to sometimes.

have you checked the #1 spark plug for spark? If you have using a simple method like a screwdriver on the valve cover, might want to try it with a voltage calibrated spark plug tester as well.

As to the prob disappearing over 2000rpms (in other words, cyl 1 starts firing at engine speeds over 2000 rpms), that is possible, but it's also possible that over 2000 rpms the cyl is still misfiring but the crankshaft is rotating fast enough that even though cyl 1 is not firing it isn't noticeable due to the speed of the crankshaft smoothing out any roughness from the firing discrepancy. Whereas at lower rpms the missing cyl 1 will cause a much more noticeable roughness.

Also I would suggest verifying the ignition timing with a timing light. It's worth doing to eliminate it as a potential cause or contributor.

WOW u kind of lost me there I had to read twice to understand it,anyhow will that be happening even though I have a brand new distributor,out the box from HONDA.I checked the timing and it was good.

Also last night when I got home I checkd for codes and pulled code 41 wich is for O2 sensor I was thinking that might b my problem, but the intructors at school said they never seen an O2 sensor cause a misfire, idk.What u think?