Help with spark issue.

[Dietbudda]

Ok i've searched, here's the issue with searching. I already replaced everything assocated with the typical spark issue. Plugs, ICM, Packs, two cases of beer and nothing.

Now bear with me, i've been 'fairly' calm up untill this very point in time

I've checked EVERYTHING. The other day we were getting misfires on #1 and #3 so i pick up a new ICM c/o Holberts, well it fixed the problem, sorta. Now i have misfires on #2 and #4. WTF!!!!!

replace aLL the plugs, check ALL the coilpacks still...misfire.

No codes for any ECM damage.no pinched wires. (Unlike last time, josh knows) No codes for short to B+ on the CPS, MEECHANICAL timing is dead on. Electornis timing is stock, same from last set-up and dead on)

I don't know what else to check.

The misfires are weird, sometimes on accel, some times on deccel but never on both. Sometimes on idle, sometimes not. Sometimes the A/F reads, sometimes it dosen't.

WTF???

P.S. It's only misfires, no knocking being picked up by the knock sensors ether.

If there's something i should be logging to help out with diag, let me know and i'll do it

[Dietbudda]

So no one has any idea? Nothing to test? Nothing else that might be suspect?

Noone has ever run into a problem like this?

Holy shit, maybe i should buy cheap ebay tails and ask how they look, then everyone would have something to say.

[317ssayzarc]

try a compression and leakdown tests, then get back to me...

and yea, i feel the same way about the stupid cosmetic hype

[Dietbudda]

weird question... if it fires on a plug outside of the engine, but misfires inside could that indicate a problem with the CPS?

[317ssayzarc]

weird question... if it fires on a plug outside of the engine, but misfires inside could that indicate a problem with the CPS?

nah i dont think so... but keep in mind firing at atmospheric pressure doesnt mean its firing under many pounds of pressure, what plugs and gap?

[Dietbudda]

NGK 7e's at .025

[317ssayzarc]

hmmm, interesting... try the comp/leakdown tests since you dont have a wideband gauge, if that checks out its down to afr... im telling you, you will regret it if you dont get the afr gauge, dont go WOT again until you do... been there, done that and please learn from my experience!

[Dietbudda]

I have a AFR gauge in there sits between 15.1 and 14.7 at idle and jumps around with the misfire.

[317ssayzarc]

how about under load? while its misfiring the afr will be a false lean due to the way an 02 sensor works, so you need to look at the afr right before it starts misfiring

[creechsa4]

check your coil pack boots (replaceable), they might be worn out leakin spark to ground. i replace mine one every 2 yrs or so, instead of the whole coil pack.

[Dietbudda]

I got it all sorted out today through good timing and sheer luck.

I got a new ICM in, tested all three icm's and the only good one was the newest one. So i'm taking the $300+ one back to the dealer and getting my coin back.

That fixed the missfire to an extent. Afterwards i was able to get decent A/F's and saw it was leaning out.
So a few quick tweaks on the second ECU and bingo, misfires gone!!!

Thanks for everyone's input!

[317ssayzarc]

awesome!

videos to follow?

[Dietbudda]

awesome!

videos to follow?

I'm sure bassed wouldn't have a problem shooting some videos once i get a decent enough street tune the boost it up enough to be worthwhile!!!

[Poopie]

i'm glad you got it running. I stopped by today around noon but no one was around so i worked on my boat.

[Dietbudda]

Yeah sorry, my rents were in town, we were ther round 2.