[CheesecakeInjection]

Hello, I am having issues with a misfire on 3, and a delayed ignition code.
Codes: CDA7, 29CF!

Only when WOT or high rpm do i get bad misfires. Its usually cleared up when i turn the car on/off.

I have a new plug and ignition coil in 3, and just got my intake cleaned with no result. When i went to bmw to get a plug i had them test the injector and they said it was good. Let me know what you guys think.

I’m thinking o2 sensors Because it clears when I restart? Not sure which one to change, and am a little skeptical because its only an issue on one cylinder . Let me know what you think!

Log of a wot pull is attached, I let off the gas not long after it started missing bad. Misfire started when i installed my jb4. It stays on with jb4 de-activated.

2010 335ix N54 e90 dct jb4 7” vrsf intercooler&charge-pipes tial BOV bms OCC

[marvinstockman]

You go lean, AFR goes up, under wide open throttle. Check fuel pressure under WOT. Weak fuel pump or clogged fuel filter.

Note, the computer resets the misfires when ignition is turned off. No misfires no cylinders will be turn off, that is, until you go WOT.

[CheesecakeInjection]

I can check that yeah. You think id get a misfire in only cylinder 3 because of the fuel pump?

[CheesecakeInjection]

I appreciate the feedback. Im no expert, but I thought when theres a misfire, unburnt air goes through the exhaust, so its picked up by o2 sensor and it reads that as high afr.

[NinetyEight740]

A bad o2 or fuel pump would not cause the misfire on a single cylinder every time. Have you checked your compression?

[marvinstockman]

If a cylinder is shut down because of a misfire, the fuel is cut off to the cylinder.

[Tonethejackal]

Have to ask? Are you using 93 octane? I get cheap often and if I have 87 in the tank I am more likely to get a misfires when I put the hammer down. Even though its new, I'd swap your coil and see if the misfire follows.

[CheesecakeInjection]

Originally Posted by Tonethejackal

Have to ask? Are you using 93 octane? I get cheap often and if I have 87 in the tank I am more likely to get a misfires when I put the hammer down. Even though its new, I'd swap your coil and see if the misfire follows.

I will check compression soon.

I use 91 octane. Its hard to get better than that where i live. I could try i some octane booster, but i dont know if itd help really.

Also, the new plug and coil are new post misfire.

[CheesecakeInjection]

Ouch. So I took it to a local indie shop. I had previously taken the injector in to get looked at by the dealer, they said it was good. Indie shop tells me all it was was the injector. I should have just bought one to try. Frustrating.

[CheesecakeInjection]

I recently used BGs Fuel injector cleaner though. So this falls into their warranty period. Pro tip for anyone who plans on tuning, use BGs fuel injector cleaner 800kms before you start tuning, and they will cover any injectors that fail up to 2000 USD.