One Bank Misfire At WOT

[R490]

Gave er the beans, and now I'm stumped. Posting in main for visibility, I had a friend look over it and he wasn't sure either.

In order of what happened:

-Made a whooshing noise from the pass side firewall

-Started stumbling above 3.5k

-Heavy fuel/exhaust smell in cabin

- Exhaust started backfiring, started running like shit

-Car was really sluggish for a few minutes, flashing CEL

-Flashing CEL cleared up, car started running better again.

-Codes are all focussed on cylinders 4,5,6 (Drivers side)

Here are the codes:

17775 Cylinder 5 Ignition Circuit
17778 Cylinder 6 Ignition Circuit: Open Circuit
17772 Cylinder 4 Ignition Circuit
17865 EGT Bank 2 (Residual, has been there for months)
16689 Cylinder 5 Misfire Detected
16690 Cylinder 6 Misfire Detected
16688 Cylinder 4 Misfire Detected
16684 Random/Multiple Cylinder Misfire Detected






The plugs I pulled all look like this (NGK PFR6Q with .030~ gap)







Coil packs are visually okay. Minus the one pictured, because it doesn't have a seal.

I did a boost leak test, nothing found. Timing is fine.

I considered an MAF issue, but I don't think a MAF issue would mess with only the right bank cylinders. Maybe an ICM? Or could replacing my plugs clear it up? I've replaced them with .025 NGK BKR7E, but I'm waiting on a coil pack seal before I button everything back together.

[V1nny]

if your coils are older than few years, would consider switching to new style coils, and getting rid of ICM's.

[Silverex]

Most likely a bad ICM for that bank

[V1nny]

ICM's could be swapped around to test. They are also sensitive to overheating, and rely on cooling from the top of air box. Best, is to get rid of ICMs, they are the weak spot of APB engine, especially when tuned above factory specs.

[R490]

Could that cause all of the symptoms I'm having though? And do ICMs throw freestanding codes?

Upgraded coils is on the list too.

[TwoSnelz]

N80 valve is right there by passenger side.. Maybe a failing check valve letting boost by?

Dunno if it would throw misfires but the fuel smell would have me looking there.

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[R490]

Purge valve has already been replaced with an OEM one.

[TwoSnelz]

Isnt there a green check valve between it and the manifold? I dont have the car or a diagram infront of me so going off memory.

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[harryn]

If you have an open circuit, and misfiring, it's a sign of a coilpack going bad or ICM going bad. I agree that you should do the ICM delete kit from 034 or ECS Tuning.

[R490]

Happened again today. But this time, it didn't clear up and I had to tow the car home. And I also wasn't at WOT, I was just casually crusing home after work.

16689- CYL 5 Misfire
16690- CYL 6 Misfire
16688- CYL 4 Misfire
16684- Multi Cyl Misfire
17778- Cyl 6 Ignition Open Circuit
17772- Cyl 4 Ignition Open Circuit
17866- EGT Sensor 2 (This one never goes away)

Still leaning ICM issues on that bank? Possibly clogged cats? Not sure where to turn.

[S4James]

ICM is the first common failure point. followed by an issue with the harness, then lastly ECU

could have a couple bad coilpacks but they dont ususualy fail in threes like that.

if you search there is a way to test the ICM with a multimeter and a 9V battery

[Monty23]

Proper combustion needs spark (at the right intensity and precise time), adequate compression (anything over 120 psi with less than 30 psi between any two cylinders is acceptable), and the correct amount of fuel (correct injection time and fuel pressure). Your ECU is detecting improper combustion on a complete bank of cylinders. It is very unlikely that all 3 plugs fouled at the same time or all 3 injectors (and only those 3 injectors) had issues at the same time or those 3 cylinders had lost compressions without a cam code and some noise/driveability issues. So, the most likely component that controls combustion on that entire bank is the ICM for that bank. Replace the ICM like has been said a few times now by multiple people and enjoy your car again...

[CELison]

ICM is the place to start. I have multiple good ones in my stash if you need one. I have no use for them.

[R490]

ICM is the place to start. I have multiple good ones in my stash if you need one. I have no use for them.

Yeah I’d gladly grab one for testing purposes if they’re just sitting around. Thanks

[PwrWgn]

FWIW when I've had ICMs fail it was only on a single cylinder. It didn't happen at WOT and the cylinder misfired continuously until the ICM was replaced. I opened it up and you could see the circuit inside the ICM was physically broken.

I'm not saying you can't fail an entire ICM, but just keep in mind that there are 3 independent circuits inside.

If you want a quick way to tell if it is the ICM, just swap the connectors and see if the symptom follows to the other bank.

Also - I believe PFR6Q is considered too hot of a plug for a tuned 2.7T

[R490]

This came back AGAIN.

16689
16690
16688
16684
17865

The ICM fixed it last time. I replaced it with a used one last time, I guess it's shit out another one.