[F87source]

Originally Posted by shaneguags

with the M2 being forced induction with a turbo and tune, wouldn't we naturally want slightly tighter spark plug gapping ? since there is more boost pressure at 22 PSI, I would need to make sure I get a spark between all the compression. I feel like going slightly smaller would help, but obviously not to the extreme of .018 like how the shop did it. I feel like .023 would be the perfect medium

No. It would not change anything. We wouldn't naturally want to go smaller, that's just a consequence of the coils being too weak and not a desire or benefit. Again you want the largest gap possible and you cannot guess or feel what that may be, only experimentation will yield the right number.


Now on a side note:

Decreasing gap size to stop spark blow out is imo a boot leg ghetto trash solution (to out things as harshly as possible, sorry but this is how I feel) to solving the spark blow out issue. what really should be done is upgrade the coil packs to be able to deliver more spark energy so the gap doesn't have to be closed despite the increase in power. That's the real proper solution, however sometimes this isn't justifiable for the cost vs. gap size requirements. For instance going from stock 0.028' to 0.026" isn't what I would call dire enough to justify upgrading coils but if you want to do it by the book then yes any time gap size needs to go down coils should be upgraded if upgrades exist. Any smaller than 0.026" and I would start considering it mandatory, I would never let the gap get to 0.023" because at that point I would consider it neglecting proper supporting mods.

[F87source]

Originally Posted by shaneguags

with the M2 being forced induction with a turbo and tune, wouldn't we naturally want slightly tighter spark plug gapping ? since there is more boost pressure at 22 PSI, I would need to make sure I get a spark between all the compression. I feel like going slightly smaller would help, but obviously not to the extreme of .018 like how the shop did it. I feel like .023 would be the perfect medium

Ok I realize my last post might be harsh, my apologies I was typing it really early in the morning lol.


Ok let me explain it in another way. The ideal gap is to be as large as possible and around 0.028" set by BMW. The fact that the car is turbo charged has little to do with gap size you still want to maximize it. Closing the gap has no real benefits and is only done when you don't have coil upgrades or you're making insane 1k whp and have no choice. So you always want the largest possible gap, regardless of NA or turbo charged.


An analogy is you're wearing sun glasses on a bright day allowing to to have your eyes fully open, and it gets brighter youre still able to keep you're eyes wide open. But at some point when it gets too bright you begin to squint (when hp increases eventually you close the gap). Eventually if it gets too bright you squint so much that you can't see anymore. Why would you keep squinting instead of buying darker glasses. Squinting is only a temporary band aide to the real problem. Just like Conti using to gap down is just a band aid, upgrading coils is better.

[shaneguags]

update : I had a few leaky injectors and just replaced all the injectors to OEM and literally 10 minutes from leaving the shop, the car had a CEL pop up. When it popped up, I was in a middle of a pull and the car dropped its power and RPMs, while foot still on gas and then shot up. (in total 3 times, foot still on gas). Car was fully warmed up, half tank, and half traction on. (maybe that's why?) As well, when warm starting the car there still minor pulsing going on with the idle bobbing up slightly once after startup. After arriving home, I checked for codes and I had was an exhaust valve code that I cannot clear and a non-available code. I went to clear the codes and reset adaptations and notice they didn't select "OEM injectors" on the tune file. I am going to reflash the tune and see if that helps and reset adaptations again. I have now replaced spark plugs, coil ignitions, and now injectors, I'm not sure why the idling still acting funny. If anyone knows how to help please let me know

[F87source]

Originally Posted by shaneguags

update : I had a few leaky injectors and just replaced all the injectors to OEM and literally 10 minutes from leaving the shop, the car had a CEL pop up. When it popped up, I was in a middle of a pull and the car dropped its power and RPMs, while foot still on gas and then shot up. (in total 3 times, foot still on gas). Car was fully warmed up, half tank, and half traction on. (maybe that's why?) As well, when warm starting the car there still minor pulsing going on with the idle bobbing up slightly once after startup. After arriving home, I checked for codes and I had was an exhaust valve code that I cannot clear and a non-available code. I went to clear the codes and reset adaptations and notice they didn't select "OEM injectors" on the tune file. I am going to reflash the tune and see if that helps and reset adaptations again. I have now replaced spark plugs, coil ignitions, and now injectors, I'm not sure why the idling still acting funny. If anyone knows how to help please let me know

Did the shop code the new injectors to the car?

[shaneguags]

Originally Posted by F87source

Did the shop code the new injectors to the car?

yes, that's what they claimed. is there a way to check that myself ? also, they are EU6 injectors, I'm reading this doesn't require coding, just resetting adaptations.

[F87source]

Originally Posted by shaneguags

yes, that's what they claimed. is there a way to check that myself ? also, they are EU6 injectors, I'm reading this doesn't require coding, just resetting adaptations.

I believe you can check on ista, and you can check flow settings too.

I believe you have to register it with the flow ratings on the side of the injectors.

[shaneguags]

Originally Posted by F87source

I believe you can check on ista, and you can check flow settings too.

I believe you have to register it with the flow ratings on the side of the injectors.

okay so I reflashed and reset adaptation again and warm started again and the idle completely stopped bobbing up. idle is normal and stays in same spot right after start up. I test drove it, shifts and power feels smooth, no weird power loss. I test started it up five times and all five of the attempts were perfect. tomorrow I will be cold starting and seeing how the car idles, knock on wood it is normal. I'll be updating this forum tomorrow with the results !

[shaneguags]

cold start this morning was perfect, no misfires or codes, 0 pulsing, and the cold start seems less aggressive on initial start up. car seems fixed now and running perfect

[Leaveatrail86]

Originally Posted by shaneguags

cold start this morning was perfect, no misfires or codes, 0 pulsing, and the cold start seems less aggressive on initial start up. car seems fixed now and running perfect

I have a pulsing, choppy idle at the moment. On e85, too. I replaced my cyl 5 injector like the scanner indicated. Only at idle, though. Fbo and gapped to .22. I had the pr ignition coil kit and when I removed it to use the stock coils it pulled much harder up top. Just don’t know if I have another possible bad injector like you?

[shaneguags]

Originally Posted by Leaveatrail86

I have a pulsing, choppy idle at the moment. On e85, too. I replaced my cyl 5 injector like the scanner indicated. Only at idle, though. Fbo and gapped to .22. I had the pr ignition coil kit and when I removed it to use the stock coils it pulled much harder up top. Just don't know if I have another possible bad injector like you?

so recently, my shop installed an intake manifold port injection kit to my car and when cold starting, the car's idle goes up but then immediately dips. it then goes back up and then goes up more (becoming very loud for like 2 seconds) but reverts back to normal. as for power goes, we had some misfires but I think it was mainly due to the tuning setup. I am on stock coil ignitions and still on .020 gap.

my shop and tuner have been data logging the car and working on small adjustments to the tune. we also recent found out that I had a small leak and a crack on my boost valve so they are currently getting new vacuum lines and replacing my boost valve.

as for before, when on 93 and replacing the injectors, the car warm started completely normal. my turner checked all the injectors when data logging and nothing seemed off. I'm hoping the rough startup goes away once picked up but I think it's normal for ethanol (as what I heard)

[ZM2]

There’s been a lot of talk about plugs recently, but could these rough idles be caused by an O2 sensor on its last leg?

[shaneguags]

Originally Posted by ZM2

There's been a lot of talk about plugs recently, but could these rough idles be caused by an O2 sensor on its last leg?

in my case it was the injectors. I never had an issue with my O2 sensor.

[F87source]

Originally Posted by ZM2

There’s been a lot of talk about plugs recently, but could these rough idles be caused by an O2 sensor on its last leg?

I'd suspect if the o2 sensors were on its last legs there would be afr flucctuations everywhere in the rpm band along with roughness.

[shaneguags]

Originally Posted by F87source

I'd suspect if the o2 sensors were on its last legs there would be afr flucctuations everywhere in the rpm band along with roughness.

AFR have been looking normal on the data logs so I doubt it's the O2 sensors. I would assume it's just from adding port injection.

[ZM2]

So, I also am now having a pretty rough idle that every now & then throws a mixture too rich code. I assume the code is a by product of the rough idle and either injectors, plugs, O2, etc, could be the issue.

The car runs absolutely phenomenal around town and at WOT. It’s just a new bad idle for some reason. Have reset adaptations several times, tried 93 vs E50, no impact.

[shaneguags]

Originally Posted by ZM2

So, I also am now having a pretty rough idle that every now & then throws a mixture too rich code. I assume the code is a by product of the rough idle and either injectors, plugs, O2, etc, could be the issue.

The car runs absolutely phenomenal around town and at WOT. It's just a new bad idle for some reason. Have reset adaptations several times, tried 93 vs E50, no impact.

any misfires ? what's the idle do when you start up the car ? rough on only cold starts or warm starts too ?

[ZM2]

Originally Posted by shaneguags

any misfires ? what's the idle do when you start up the car ? rough on only cold starts or warm starts too ?

I will get misfire codes every now and then when the idle is rough, but the car runs super smooth except at idle— no normal driving or under load misfires. Bad idle can be cold start or warm start. Here’s a log that I just took that shows idle, slow driving, and wide-open throttle.

https://www.bootmod3.net/log?id=62ec...729b2d5d51f8d2

[F87source]

Originally Posted by ZM2

So, I also am now having a pretty rough idle that every now & then throws a mixture too rich code. I assume the code is a by product of the rough idle and either injectors, plugs, O2, etc, could be the issue.

The car runs absolutely phenomenal around town and at WOT. It’s just a new bad idle for some reason. Have reset adaptations several times, tried 93 vs E50, no impact.

Do you run a tank of pump gas between tanks of e mixes? Ethanol is now to gum up injectors over time, to solve this run a tank of pump gas every 2 tanks of ethanol and run some fuel system cleaner before oil changes. Too cylinder lube will completely solve all of this too.

[shaneguags]

Originally Posted by ZM2

I will get misfire codes every now and then when the idle is rough, but the car runs super smooth except at idle— no normal driving or under load misfires. Bad idle can be cold start or warm start. Here’s a log that I just took that shows idle, slow driving, and wide-open throttle.

https://www.bootmod3.net/log?id=62ec...729b2d5d51f8d2

not gonna lie, I have this exact problem… it only happened when I introduced ethanol. I have new plugs, injectors, and fairly new coils so I doubt it's those.

[shaneguags]

Originally Posted by F87source

Do you run a tank of pump gas between tanks of e mixes? Ethanol is now to gum up injectors over time, to solve this run a tank of pump gas every 2 tanks of ethanol and run some fuel system cleaner before oil changes. Too cylinder lube will completely solve all of this too.

does this include port injection setups as well ?

[F87source]

Originally Posted by shaneguags

does this include port injection setups as well ?

If your pi injectors are e85 rated then chances are no, but I'd still run top cylinder lube or run a tank of pump gas between every few tanks of ethanol to clean everything up. Especially if your car sits alot. Fuel system cleaner before every oil change helps too.

[shaneguags]

Originally Posted by F87source

If your pi injectors are e85 rated then chances are no, but I'd still run top cylinder lube or run a tank of pump gas between every few tanks of ethanol to clean everything up. Especially if your car sits alot. Fuel system cleaner before every oil change helps too.

got it, I appreciate the suggestion. I daily drive my car so I feel like I should be okay. but I'll make sure to use a fuel system cleaner and try full 93 here and there. I'm using flex fuel so that should be no problem