misfire on cylinder 7 and 8

[Roll]

😡😡😡😡😡

I replaced the bank 2 MAF sensor.
Cleared codes and the car drive great for about 20 miles.

Started it up after running into the store - drive train malfunction

This time, I have misfire on cylinders 1,2 and 4.
Still getting the same :rich mixture code, but the misfire on cylinders 7 and 8 are now on the other bank.

[1004ron]

Sounds like those eBay NGK spark plugs.

[Roll]

????

Dude, what are you talking about?
Plugs and coil packs are from Rock Auto.


If I look past your sarcasm, are you inferring changing the rest of the plugs and coil packs might solve my problems?

[tfunk88]

I’m having a little trouble following this…

Do I have this correct?

1. You initially have bank 2 rich, bank 2 rich large deviation, and misfires on 7 and 8.

2. You replace spark plugs and coils on 7 and 8.

3. You now still have bank 2 rich and new misfires on 1, 2, and 4 but no longer 7 and 8

The bank 2 rich sounds like injectors to me, unless you have a leak between the turbo outlet and the cylinder.

The misfires could be plugs or coils (what did the plugs that came out look like?) or could also be coils that aren’t all the way on the plug or the connectors to the coils aren’t 100% inserted. It’s easy to be just a little bit off and not notice.

[Roll]

The rich mixture code I'm getting now does not specify which bank.

I changed the 2 plugs and coil packs earlier this week with no results. Today, I changed the MAF sensor on bank 2. That's when the misfires switched to bank 1 and the code is just : mixture rich.

[tfunk88]

Ok, so you changed plugs/coils on 7 and 8, still misfires, but then MAF bank 2 change and those misfires went away? But suddenly you have misfires in bank 1 cylinder 1,2, and 4?

And a “mixture rich” without a bank specified doesn’t make sense to me…do you have the actual code number?

[Roll]

118102
Mixture control 2: mixture too rich.


And you are correct about the misfires switching from 7 and 8 to 1, 2 and 4.

[tfunk88]

That’s still bank 2. So either injectors are putting in too much fuel, or you have a leak between the turbo outlet and the intake valves. In other words a leak on the pressure side.

As for the misfires…that’s weird that they seem to have “swapped” sides. Perhaps swap your new bank 2 MAF with the bank 1 MAF you haven’t changed to see what happens.

[stocktree]

Clean the maf again. See what happens. Maybe excessive oil vapor is getting it dirty

[tfunk88]

The PCV lines don’t enter the intake stream until after the MAF so I wouldn’t think that would be an issue…but ya never know.

[zero2sixtyZ]

The codes do sound like injector or MAF issues. At that mileage, I would do preventative injector replacement if you haven't had them done under the warranty.

Originally Posted by 3002 tii

Just realized you have a N63, hope it’s not fuel pump. I forgot if the TIS covered 2015 X5’s. But I would not throw parts at it yet as that can get expensive really fast.

I wouldn't rule out HPFPs as there is one per bank, if you haven't replaced yet. Not a horrible cost if you use FCP to find the OE Bosch part. ~$150 each, plus gaskets.

https://f15.bimmerpost.com/forums/sh....php?t=1968587

[tfunk88]

While at 150k miles changing the HPFP’s wouldn’t hurt, so far he hasn’t had any low fuel pressure codes…but honestly changing them and injectors would be a great way to freshen up the old fuel system and eliminate them as issues.

With that continuous bank 2 rich, even after replacing the bank 2 MAF, I’d be leaning towards injectors or a leak in the intake post turbo. Possibly the intercooler, or any of the tubing between the turbo and the intake manifold, possibly even the intake manifold itself.

Also I’d replace at least the other spark plugs vs just the cylinder 7 and 8 that have already been replaced. Haven’t gotten an answer as to what those plugs looked like when they came out.

[Roll]

I had started doing research on swapping out HPFP. And while it's cheaper than injectors, it's still $500+ I didn't want to spend if it didn't fix the problem.

I swapped the new bank 2 MAF with bank one today and ran a few errands. Car idles almost normal and runs pretty well. I don't drive the car often, but when I kicked down to passing gear it is surprising how much pep the car has.

After a few miles (5 - 10), the CEL came back on. I pulled the codes - no misfires (at the moment), but same mixture too rich.

Your last post you indicated you didn't believe it would be HPFP cause no low pressure code. I had wondered any that. So now I'm researching changing injectors.


Again, thanks a ton for your continues interest!!

[tfunk88]

So now it’s running well with new MAF in bank 1 and old MAF in bank 2, but still with bank 2 rich code. That you’re getting a CEL means it’s occurring often. If it was only occasional bank 2 rich pretty sure you wouldn’t get a CEL. Injectors are a definite possibility, but I’d also pull the air box and check as much of the airflow path from the turbo outlet to the intercoolers to the intake manifold as you can. Like you found the turbo inlet tubes basically hanging there, you may find another obvious thing allowing air to escape.

[Roll]

Happy Easter!


I am getting 118002 and 118102.
Is that fule mixture too rich on both banks? Or just 1?

[tfunk88]

From what I could find that is both banks

[Roll]

Still trying to sort this out.
A couple self inflicted wounds...

I replaced bank 2 HPFP -
I'm getting mass air flow electrical error. I had this issue sorted once, now it's back. This is the new MAF sensor I installed. Look at the blemishes on the shiny part - Would this affect functionality???

This is the weirdest vehicle I've ever worked on, trying to chase codes.


Also getting 12008
Lambda sensors in front of catalytic converters reversed. I haven't gotten that code from the start. And I haven't touched those sensors.

Thanks for your replies.