X6M Bootmod3 OTS Stage 2 limp mode

[pablom2c]

Hi,

I'm running OTS 91 oct stage 2 tune on a 2017 X6M F86 with Active Autowerke catless downpipes.

The car has been running the tune for around a month and already twice it has gone into limp mode. When I restart the car the error goes away and then the car runs fine.

Running the car stock does not cause the limp mode and currently it has 19,000 miles.

Should I change spark plugs (1 step or 2 step colder)? new coils? I read other threads and they say it could be the fuel pump or injectors? Anything else?

Codes from Carly are:

- 140020 combustion misfires, plurality of cylinders
- 140010 misfiring, several cylinders
- 140110 misfiring, cylinder 1
- 140001 combustion misfires, plurality of cylinders, injection is switched off
- 140101 misfiring, cylinder 1, injection is switched off
- 140011 misfiring: injection cut
- 481B15 : KL30 reset (???)

First step to diagnose I'm thinking to switch coil and spark plug from cylinder 1 to see if the error moves to the other cylinder?

What else can be done? Please help me diagnose, thanks.

[MBoss_F86]

Youtuber Edward M cars had the same issue with Stage 1 91 OTS on his F85. He had to change to NGK 1 step colder plugs gapped at 0.022. All your errors also point to spark plugs. BM3 also recommend 1 step plugs with their tunes

[NikNala]

Get NGK 97506(buy from a trusted source such as Rockauto)and gap them to .022. It will solve your problems.

[pablom2c]

Great I will start by changing to the NGK plugs, hopefully it is resolved.

Thanks guys.

[StatenEye]

Coils, its almost always coils. Before you go messing around with the other coils just go grab one from Autozone and plug it in. Just noticed ur in SA, what ever the generic parts shop is down there.

[4everkidd]

Originally Posted by StatenEye

Coils, its almost always coils. Before you go messing around with the other coils just go grab one from Autozone and plug it in. Just noticed ur in SA, what ever the generic parts shop is down there.

Wrong…
If it was coils the problem would persist with the stock tune.

I agree on the plugs.

[StatenEye]

Originally Posted by 4everkidd

Wrong…
If it was coils the problem would persist with the stock tune.

I agree on the plugs.

My last 3 M cars all had a coil or two go bad after flashing. If you agree on the plugs, using your logic, shouldn't all cylinders be misfiring.. since he's asking if he should go a step colder? Guess I just got super lucky 3 times in a row with 3 stage 2+ cars running stock plugs and faulty coils.

[kkowalsk]

Increased boost pressure requires increased voltage to bridge the spark plugs gap.

This puts a higher demand on the small pencil coils.

Your coils while not that old may not have the output required to create an arc with the increased chamber pressure. The coils may not have failed however no longer have the same output as new. This is why there are no issues when running stock.

Reducing the plug gap can help since it reduces the voltage required from the coils to spark however can impact the rate of ignition. However probably not noticeable.

Spark plug heat range has nothing to do with the spark itself. Heat range is how much heat the ceramic core nose and center electrode of the plug retains. Too hot of a plug creates pre-ignition and too cold the plug doesn't get hot enough to self clean and will carbon foul. Increased boost pressures increases cylinder temps and one step cooler plug can prevent preignition that is really detrimental to an engine.

The free test is to measure and re-gap your plugs to .020"-.022". Being Iridium tipped plugs when gapping do not press against the center electrode tip. This can cause the brittle Iridium tip to chip or fracture.

The all in is new coils and one step cooler plugs gapped at .022" like said by others.

[StatenEye]

Originally Posted by kkowalsk

Your coils while not that old may not have the output required to create an arc with the increased chamber pressure. The coils may not have failed however no longer have the same output as new. This is why there are no issues when running stock.

Reducing the plug gap can help since it reduces the voltage required from the coils to spark however can impact the rate of ignition. However probably not noticeable.

This has been my experience with 3 M cars with similar age on plugs and coils. Coils were the point of fault in my 3 cases. So easy and cheap to just grab a coil from the local shop and chuck it in. 10 min job, 20 mins for the back banks.

This is my 4th S63 variant running S2+ with stock plugs.