E38 750il Fuel Trim Bank 1 & 2, Random Misfire cylinder 7-12

[masu3701]

Having codes for Fuel trim bank 1 and 2 and cylinder 7, 8, 10,11,12 misfiring.
the car seem to run fine, I can notice very little rough idle at cold start but get normal once the engine is worm.

Here is a picture of the live data:

20170522_170406.jpg

[cazal740i]

I chased these codes on my e39...fuel trim codes are usually O2 pre cat sensors...misfires are coils related

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fuel trim 2 is bank 2 or cylinders 7,8,9,10,11 and 12

[masu3701]

I chased these codes on my e39...fuel trim codes are usually O2 pre cat sensors...misfires are coils related

- - - Updated - - -

fuel trim 2 is bank 2 or cylinders 7,8,9,10,11 and 12

My 750 doesn't have the eCats. they were removed and traight pipes were installed. I always had code related to the O2 sensors because of that, but
never had codes for Fuel Trim 1 and 2.

I am thinking maybe vacuum leaks. Will inspect both PCV valves at the back of the intakes for cracks.

also when reading the LIVE data, I see LT FTRM 1 is at 15 and LT FTRM 2 is at -5, and those values dont really change, they just read that.

[XAlt]

You still have O2s "precats" -> right before the straight pipes.

Brake cleaner test works well enough in this case, I assume your intake gaskets were resealed because they are the #1 cause of cold start stumbling.

[masu3701]

You still have O2s "precats" -> right before the straight pipes.

Brake cleaner test works well enough in this case, I assume your intake gaskets were resealed because they are the #1 cause of cold start stumbling.

Yes the intake gaskets were sealed, and I still have the precat 02s.

[RIboater]

What the V8 guys call the PCV valves, on the V12 are called regulating valves. Serving virtually the same purpose I suppose. I replaced both of mine over 5 years ago but reused the rubber boots. I'm now dealing with an occasional rough idle ranging from mild to severe. comes and goes. Getting the misfires on bank 2. Has to be happening to hear the vacuum leak and when i got home tonight it was. The valve on the passenger side which feeds bank two is nearly impossible to get at to remove. I had luck with a torx bit and box wrench on it. Found the boot had a tear in it.
I think I've found the most ridiculously priced part on an E38. Might go with permatex to repair/seal it first just to be sure it's my rough idle problem.
http://www.realoem.com/bmw/enUS/show...diagId=11_1432
http://www.ebay.com/sch/i.html?_from...702292&_sop=15

[psjr]

What O2 sensor codes do you have?
The only code that should be caused by cat delete is "catalyst efficiency".

[masu3701]

Still struggling with my fuel trim bank 1 and 2.

Today i replace driver side valve and boot, I notice that Short term bank 1 and 2 are now running normal range then before where short term bank 1 was stock at 19%.

Now Long term bank 2 is stock at -12.5. When I give it gas to accelerate it would go do -3 then right back up to -12.

See picture below.

20170908_213351.jpg

Will Long term readjust it self? I did reset the code but range still -12 on long term bank 2.

[Ray43]

Can anyone pls help me diagnose my fuel trim for a 2011 Bmw 750li. 02b1s2(v) 0.590. 02b2s2(v) 0.670. Shrtftb1s2(%) n/a. Shrtftb2s2(%) 99.2. Shrtft2(%) 3.1. Longft2(%)-17.2. Shrtft1(%) 0.0. Longft1(%) -22.7...Do I need an 02 sensor ? If so where is it located at as well? Thanks...

[goinstrong]

While my E38 is the 4.4, I had the same issue with Fuel Trim Bank 1 and Bank 2, plus random misfire and misfire cylinder 1 and 2. I just replaced the OSV/PCV diaphragm (great youtube on it from Nathan DIY) (took me 5 minutes!) and the valve cover gaskets. Ended up being 1 bad coil pack (cylinder 5) and a faulty MAF. A new MAF took care of the problem, and it just passed emissions today. Hope that helps!
Tim