New Motor + PTF tune = Can't resolve missfire and timing drop issue. (Experts needed)

[Artsoasis]

I keep getting Cylinder 6 misfires at WOT 6,200+ RPMs and Cylinder 5 timing drops on my new motor. I have tried many things, but I can't seem to fix these issues.

Log of Cylinder 6 misfire: http://datazap.me/u/artsoasis/ptf-v1...cylinder-6-log

I'm completely at a loss on what to do.

So far I have:
Changed plugs to new NGKs gaped to .018
Purchased brand new Delphi Coils
Switched Injectors ( 6 to 3, 5 to 2)
Compression test checked out fine at 150 across the board.
Performed boost leak test

The only things I have remaining to check out are:
Logging port injection
Switching out port injection injectors

Car info:
2011 335is DCT (New motor with 1,756 miles just installed)
Vargas Stage 2+ Turbos w/ inlets
Fuel it Stage 3 LPFP
Fuel-it Port injection
AIC 6 controller
VRSF 7" FMIC
N20 Tmap sensor
RB external PCV upgrade
Downpipes

[jyamona]

AFR's in the 20's from 2000 - 2800 rpm on that first log? Eesh. You also max STFT for a data point. Tune needs work. Also, I see timing drops on multiple cylinders, not just 5.

[Artsoasis]

Do you see anything that would be causing these Cylinder 6 misfires? @jyamona@motiv

[alex@ABRhouston]

Probably detonation, mang

[Artsoasis]

Detonation how and why?

[Tony@VargasTurboTech]

Its an injector, I know you said you changed them, but its an injector. I know this from direct experience. When making these upgrades, cars that ran PERFECT will $#@! injectors instantly when asked to make more power. Case in point, got out AT car up and running on Friday. Car ran, idled, everything fuel wise perfect. First I mean first pull on the dyno. Injector 6 $#@! the bed, dead miss in that hole. Replaced it, fixed ran a couple more time, it was fine made 620WHP on low boost. Took it to the event, ran it once, #6 misfire, swapped injector first thing with "known good" injector. Same thing, finally after chasing my tail for another 2 hours. I put one of the brand new injectors I had brought with me in #6 . Problem instantly fixed. Not another misfire in that hole. the car started eating other injectors though. Keep in mind this car had index ONE injectors in it. I have never even seen a set of index 01 injectors in my life.

Bottom line, components that work perfectly when asking for 450-500WHP, will show their age quickly when you ask for 600+. Its exactly why I just took this entire car apart, and replaced everything, I should have done the injectors but ran out of time, its why I brought a full set of new ones to the event.

Do yourself a favor, make sure you have NGK 5992's in tehe car gapped to nothing bigger than .20, and replace all 6 injectors with BRAND new ones, not remans. I am willing to bet your problem goes away.

Also your midrange fueling is out to lunch, my guess is your PI set up is all wonky, you need to get your PI map dialed in, and do the things suggested, the issues will go away.

A side note, you should not be seeing any corrections at all, on that low of boost. Injectors can cause that as well. How long ago since last walnut blast?

[Tony@VargasTurboTech]

For reference. First log is the injector misfire I kept getting over, and over. Look familiar? Next log is with every injector but 1 swapped with new ones in the pits, then right back out.

Notice it also fixed most my corrections. You can see the time stamp on the logs, same map, about half an hour difference, as I am fast at hot swapping injectors. Cleaned up the corrections, and fixed the misfire. When it misfires it sends you into open loop, thats why your trims go to 0, the car can no longer adjust fuel up or down. Usually when you go open loop if you stay in it, the car goes very lean.

Check out my fueling in second log, how much better it is.

People ALWAYS underestimate how many issues these stupid injectors cause.

Old injectors Misfire log: http://datazap.me/u/vargasturbotech/...1&zoom=141-207

Swapped injectors no other changes: 160MPH pass on same tune: http://datazap.me/u/vargasturbotech/...4&zoom=157-376

[cloakedm3]

i have also seen cyl 6 engine miss fires from a clutch install from over tightening of the bell housing bolts. this is happening when you install the steel bell bolts and it distorts the cyl on #6 enough to cause a miss fire just one thing to check TQ value and make sure its correct

[Sticky]

What did the tuner say?

[Tony@VargasTurboTech]

What did the tuner say?

If he were not in bed he would tell everyone he has a 103 fever, and is extremely sick. Tuners are not usually the best people for diagnosing mechanical issues, I can assure you OP, this issue has nothing to do with your tune. If you have not swapped your injectors, swap them, use the INPA to code them, and I bet you are smiling ear to ear

[The Ghost]

If he were not in bed he would tell everyone he has a 103 fever, and is extremely sick. Tuners are not usually the best people for diagnosing mechanical issues, I can assure you OP, this issue has nothing to do with your tune. If you have not swapped your injectors, swap them, use the INPA to code them, and I bet you are smiling ear to ear

He swapped the plugs and injectors but the misfire didn't follow the injector nor plugs. Compression is good and consistent across all 6.

[The Ghost]

i have also seen cyl 6 engine miss fires from a clutch install from over tightening of the bell housing bolts. this is happening when you install the steel bell bolts and it distorts the cyl on #6 enough to cause a miss fire just one thing to check TQ value and make sure its correct

Really, you loosened it and it fixed the misfire? Are you talking about the top bellhousing bolts (12 and 11 o'clock)?

[Tony@VargasTurboTech]

He swapped the plugs and injectors but the misfire didn't follow the injector nor plugs. Compression is good and consistent across all 6.

You guys are not hearing me. Sometimes for whatever reason certain cylinders will either have higher cylinder pressure, a hot spot, any number of things. Swapping old injectors around, the problem will not always follow as its a problem with that hole and old injectors. In my post, I swapped #6 with a known good injector that was 100% fine in another motor, but still used. Issue persisted, finally put a new one in it, problem gone. These cars at high power levels are EXTREMELY sensitive to injector issues.

OP if you are looking for consistent 600+WHP you want new injectors anyways, bite the bullet, and install them

Also OP if you really want to test it, just turn off misfire detection in bank 2, take a log, look at the trims and AFR where it normally misfires, if you see any anomalies in either you can be sure its the injector.

[cloakedm3]

Really, you loosened it and it fixed the misfire? Are you talking about the top bell housing bolts (12 and 11 o'clock)?

loosed all of them and re tqed all of them another shop did the clutch job and after the clutch job it developed a miss fire and it came to us and we found through the grave vine from BMW that this has been a on going issue with guys installing new clutches and upgrading to steel bolts having this issue after the install....i'm not saying this is your issue but it is definitely a easy cheap check and fix if that is your problem.

[The Ghost]

loosed all of them and re tqed all of them another shop did the clutch job and after the clutch job it developed a miss fire and it came to us and we found through the grave vine from BMW that this has been a on going issue with guys installing new clutches and upgrading to steel bolts having this issue after the install....i'm not saying this is your issue but it is definitely a easy cheap check and fix if that is your problem.

Good to know. Makes me wonder if installing brass washers on the bolts would help any.

Thanks for the tip.

[The Convert]

loosed all of them and re tqed all of them another shop did the clutch job and after the clutch job it developed a miss fire and it came to us and we found through the grave vine from BMW that this has been a on going issue with guys installing new clutches and upgrading to steel bolts having this issue after the install....i'm not saying this is your issue but it is definitely a easy cheap check and fix if that is your problem.

That is insane, but makes sense. Do you mind posting what the torques values are for the steel bolts? Thanks!

[Velocity26]

The (expanding) fuel injector seal is only good for one install and then must be replaced and compressed. If you swap injectors without replacing the seal, you are likely creating the kind of leakage that can cause high rpm misfires. If you can remove an injector with minimal resistance, your seal was likely bad. New injectors/seals usually require some force to seat completely. If the injectors goes into place with little to no resistance, you likely have a bad seal or eroded injector tunnel.

[cloakedm3]

[Itsbrokeagain]

Its an injector, I know you said you changed them, but its an injector. I know this from direct experience. When making these upgrades, cars that ran PERFECT will $#@! injectors instantly when asked to make more power. Case in point, got out AT car up and running on Friday. Car ran, idled, everything fuel wise perfect. First I mean first pull on the dyno. Injector 6 $#@! the bed, dead miss in that hole. Replaced it, fixed ran a couple more time, it was fine made 620WHP on low boost. Took it to the event, ran it once, #6 misfire, swapped injector first thing with "known good" injector. Same thing, finally after chasing my tail for another 2 hours. I put one of the brand new injectors I had brought with me in #6 . Problem instantly fixed. Not another misfire in that hole. the car started eating other injectors though. Keep in mind this car had index ONE injectors in it. I have never even seen a set of index 01 injectors in my life.

Speaking of, the project car I just finished is on the original injectors at 94k. 9/06 build

[Tony@VargasTurboTech]

Speaking of, the project car I just finished is on the original injectors at 94k. 9/06 build

I promise you the second you put any power to it, they will go. This car was on index 01's. Build date 02/07. First pull even at low boost, basically just blew one out. Car ran perfect before that.

[Tony@VargasTurboTech]

The (expanding) fuel injector seal is only good for one install and then must be replaced and compressed. If you swap injectors without replacing the seal, you are likely creating the kind of leakage that can cause high rpm misfires. If you can remove an injector with minimal resistance, your seal was likely bad. New injectors/seals usually require some force to seat completely. If the injectors goes into place with little to no resistance, you likely have a bad seal or eroded injector tunnel.

This is not what is causing misfires, the injectors are over fueling. Compression leaking past the seal will be just that compression leaking past the seal. Its not going to cause a misfire, an injector that is not spraying properly, either too much fuel (99%) of the time, too little fuel, or very poor spray pattern will cause this. The seals while important can be swapped around multiple times without issue. You can argue with me all you want, I have done it for years, without an issue. The problem is, when people do these builds, they not only crank boost, timing, and cylinder pressure at the same time, they usually throw a new fuel into the mix. All of this is a recipe for injector failure, which sometimes means the car runs perfect under all circumstances except putting a greater load on it than you previously had, then you get misfires.

[alex@ABRhouston]

This is not what is causing misfires, the injectors are over fueling. Compression leaking past the seal will be just that compression leaking past the seal. Its not going to cause a misfire, an injector that is not spraying properly, either too much fuel (99%) of the time, too little fuel, or very poor spray pattern will cause this. The seals while important can be swapped around multiple times without issue. You can argue with me all you want, I have done it for years, without an issue. The problem is, when people do these builds, they not only crank boost, timing, and cylinder pressure at the same time, they usually throw a new fuel into the mix. All of this is a recipe for injector failure, which sometimes means the car runs perfect under all circumstances except putting a greater load on it than you previously had, then you get misfires.

I disagree wholeheartedly here, Tony.
Those injector seals are critical to misfires and not hurting the cylinder head.
Those injector seals need to be replaced EVERY single time. Period.

If not, hot compression blows past it, cuts the head up like a cutting torch and tosses the injector out of the head.
I've seen it and repaired it multiple times.

Now, as a DIY you can take your chances- but as a professional shop and my name on it? No way, and if I saw or knew of my techs not replacing them, they'd be sent home.

[CKI@Motiv]

This is not what is causing misfires, the injectors are over fueling. Compression leaking past the seal will be just that compression leaking past the seal. Its not going to cause a misfire, an injector that is not spraying properly, either too much fuel (99%) of the time, too little fuel, or very poor spray pattern will cause this. The seals while important can be swapped around multiple times without issue. You can argue with me all you want, I have done it for years, without an issue. The problem is, when people do these builds, they not only crank boost, timing, and cylinder pressure at the same time, they usually throw a new fuel into the mix. All of this is a recipe for injector failure, which sometimes means the car runs perfect under all circumstances except putting a greater load on it than you previously had, then you get misfires.

So a injector seal leaking compression wont cause a misfire but a injector, injecting to much fuel will?

So a leaking injector seal leaking compression creating a rich cylinder (less air same fuel) is different than a fuel injector injecting to much fuel. Only one of those scenarios causes misfires but the other doesnt? explain

[Tony@VargasTurboTech]

Alex while I respect your opinion on a lot of things. This one I just don't agree. I have never replaced one ever swapping injectors. Not one, I have never seen a single sign of ANY ZIP ZERO NADA compression leak past a single injector. This is also not going to cause injectors to leak. Everyone has their opinions, BMW tells people all 3 injectors have to he replaced at once, we all know that's not the case. We can agree to disagree here. There is no such thing as an invisible leak, I've been doing this long enough to know, ANY leak will leave either a witness mark, or its calling card. A high compression cylinder leak from the combustion chamber would leave obvious signs of leakage. As I said I have never seen one. You can replace seals every time if you would like. If we are working on a customers car we would never put anything in except brand new injectors so that's brand new seals. On my own stuff, I won't be changingthem

[Tony@VargasTurboTech]

So a injector seal leaking compression wont cause a misfire but a injector, injecting to much fuel will?

So a leaking injector seal leaking compression creating a rich cylinder (less air same fuel) is different than a fuel injector injecting to much fuel. Only one of those scenarios causes misfires but the other doesnt? explain

Love it guys, LOVE it! You must also believe in invisible leaks. Show me a leak from a high compression chamber that isn't leave a witnes mark, and I'll show you no leak. I have done as much testing as you, if not more. I know that these engine do when they are running bad, 9 times out of 10 it's an injector. Next you are going to tell me. Well it's sucking air past the seal that's why it misfires. So it's sucking air past the seal, but the exhaust is not leaving a telltale witness mark as it escapes. You guys can continue to argue, I'll continue to know exactly what a leaky injector looks like in a log, and fix the misfire with a simple injector swap. Carry on with the discussion.