Help with N54 Cyl-1 Misfire Please!

[KPDcompany]

I have posted on n54tech and have gotten great help, as well as e90post, but still havent fixed it, so I wanted to get some other input from some others. Car is stock turbos, FBO on E60. Cylinder-1 misfire is consistently at high rpm near redline and would not happen on jb4 map 1, but does on map 7. I have swapped coil packs between cylinders 1 & 2, swapped spark plugs between 1 & 2, put new NGK plugs in gapped at 0.019(95770, new 5992's) and then just yesterday put a new index 12 injector in cylinder 1, coded correctly and still the same misfire. Which really sucks because that means the injector I pulled out was fine, it was dirty, but really not nearly as bad as you would normally see. All coil pack wiring grounds are tight and have been loosened and re-seated. I am not sure what could possibly be going on. It would not let me attach a csv log from this morning when it misfired, so I put a link to the datazap log. As you can see in the log, all cylinder ignition timing look to be identical but cylinder 1 still differs from the other 5. I am at a loss here and hopefully someone here can give some insight. I have new OE Bosch plugs that I will but in this evening to see if that fixes anything at all.


https://datazap.me/u/kpdcompany/another-mis?log=0&data=1-4-11-25-26-27-28-29

 

[Rcboosted2007]

 

[KPDcompany]

Thank you for looking into this, I really appreciate it. It has a 450 walbro and about E60 fuel in it. It is weird. From what I thought it was cutting injector in cylinder 1 for some reason? I thought it was "sensing" a misfire situation and cutting that cylinders fuel, which in turn is why the afrs went up, is what i thought. It doesn't make any sense to me. The only thing I was thinking it could be is that cylinder 1 injector seal is loose, maybe from previous someone did it wrong? I was going to replace the oring tonight and see if it fit tighter as it does feel looser than others, but there is no combustion blow by past the oring, but maybe the higher boost is allowing the injector angle to be moved therefore making it sense a misfire? Maybe this isn't the case? Have any other thoughts or does that sound plausible?

 

[Rcboosted2007]

Atleast its down to a few categories lol. And issue seems to be in bank 1 only

1-)Fuel.
2-)Sensors. Pressure,oxygen,tmap which seem okay.
3-)Air leaks

 

[Rcboosted2007]

http://www.e90post.com/forums/showthread.php?t=1120250

 

[Rcboosted2007]

I feel it more of a control issue then a hardware issue, only becausw you dont have such issues with a more conservative log, etc. I ended up going PI. To eliminate the e85 mixing mess, and now run full e85

 

[KPDcompany]

I feel it more of a control issue then a hardware issue, only becausw you dont have such issues with a more conservative log, etc. I ended up going PI. To eliminate the e85 mixing mess, and now run full e85

Ok got ya. It seems like fuel pressures are ok, but from what it looks to me the fph only drops when it misfires. Also fyi i havent had any other codes, but not sure if a sensor could still be bad? The weirdest thing is cyl1 injector is brand new, as well as all plugs. but still misfiring or sensing a misfire there. I can check for air leaks, but I feel like if that were the case I probably wouldn't be hitting boost target would I? The only reason I thought cylinder 1 injector seal/bore is cause I could wiggle that injector, it is new so maybe its a faulty seal that isn't expanding like it should, and I just figured the reason it arose on higher boost was because of that extra pressure increase causing the injector to be able to wiggle or move thus causing it to think its going to misfire due to that variance? I thought about turning off misfire detection on the flash to see if it still actually "misfires" or if its just sensing that its going to or thinks it is. What kind of control issue would you think it would be?

 

[Rcboosted2007]

Could be. I used to turn settings off/ desensitize knocks also....RIP to my previous motor.but i left settings that way for active races. Just a word of caution

 

[KPDcompany]

Could be. I used to turn settings off/ desensitize knocks also....RIP to my previous motor.but i left settings that way for active races. Just a word of caution

Think one pull to redline in 3rd will make her pop? if so, im good, haha

 

[Rcboosted2007]

No regrets here! The supercharged new 5.0 was covered by the huge smoke screen the car let out AND I KEPT PULLING AWAY

 

[KPDcompany]

No regrets here! The supercharged new 5.0 was covered by the huge smoke screen the car let out AND I KEPT PULLING AWAY

HAHA, I just built a house, and about to have a patio done, so I would have regrets, hah.

BUT I did turn it off, ran great, no misfires, but boost was a little lower than it was when misfiring. I had my tuner do it for me, and he is going to adjust it some to get boost up to verify. But it ran fantastic and he said everything was Perfectly healthy. So its looking like something is causing a false sense of misfire. any ideas?

 

[Rcboosted2007]

http://www.e90post.com/forums/showthread.php?t=1120250

Maybe something similar

 

[KPDcompany]

http://www.e90post.com/forums/showthread.php?t=1120250

Maybe something similar

My trims are fine though?

 

[Rcboosted2007]

Leaning more toward a degrading knock sensor.maybe your tuner can come under with a creative way to prove that prior to replacement. Save some money for some nice cafe lights for your patio lol.

 

[KPDcompany]

Leaning more toward a degrading knock sensor.maybe your tuner can come under with a creative way to prove that prior to replacement. Save some money for some nice cafe lights for your patio lol.

Haha. Really think its a knock sensor without a code? What kind of creative way would you suggest? Weird how its only one cylinder though? I figured it was something else maybe.

 

[Rcboosted2007]

If nothing went wrong with your run mechanically, fuels good, tune is good. Then something is Causing a false misfire condition.

 

[KPDcompany]

If nothing went wrong with your run mechanically, fuels good, tune is good. Then something is Causing a false misfire condition.

Ya, but what? sh*t is crazy!

 

[Rcboosted2007]

Maybe activate misfire detection, and desensitized knocks

 

[KPDcompany]

Maybe activate misfire detection, and desensitized knocks

Alrighty, I'll give it a shot

 

[Sinis1er_e82]

Alrighty, I'll give it a shot

Any updates on this issue? My tuner and myself are going through this exact issue. Thought we pinned it down to needing more timing up top but only worked for slightly lower boost

 

[matreyia]

If you have a specific misfire regardless of the tune fixing it or not... and you changed coils and injectors it means that the specific valve needs physically inspected and or cleaned. There is nothing else that can be the issue. High power tunes increase misfire potential but the fact that it is only one specific cylinder shows a physical issue.

When was last walnut blast? A yr ago? If so... do it again. I do yearly.