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Discussion Starter #1
Hi Guys, I desperately need some help.

My e60m5 has a misfire I cannot seem to cure but the odd part is it goes away and the car runs 100%. Then it comes back again. This leads me to believe it’s not something physical/mechanical.

The codes I get are the ‘cylinder misfire effecting emssions’. Then ‘cylinder misfire with cutoff’ then ‘multiple cylinder missfire’ I also reliability get o2 sensor at limit position (like due to misfires). I also have the airbag error from the ‘resistance to high’ on the cable in the boot that has the emergency battery disconnect.

I have tried:
Full set of the reccomended ngk spark plugs
Full set of brand new coils (the oem/bremi ones)
Both bank 1 ionic module and bank 2 ionic module (also brand new oem).

The symptoms are like this:

At cold start it runs horribly and immediately goes into ‘reduced power’ (aka limp mode). At first it’s so rubbish the car barely drives. With about 2 minutes of driving it warms up enough that it’s running better. After 5 min when oil temp is around 90c I turn off the car and restart and it’s running fine with just an occasional slight miss. If i get stuck in traffic idling for extended time it will usually hit limp mode again. If I’m on a freeway drive it runs very nicely. It’s happy to pull up to an easy 150mph.

I’m happy to do the alternator but blowing a bunch more money doesn’t appeal if it won’t fix it. The coils and ionics did nothing.

I’m wondering if it could be a bad coolant temp sensor?

Some of the codes:
2B3C - missfire cyl 8 with cutoff
2B49 - missfire cyl 8 impairing emssions
27AA - 02 sensor at limit bank 1 pre cat


The fact that this issue can come and go tells me it’s likely a sensor or some electrical issue.

Any thoughts greatly appreciated!
 

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How are the fuel pressure scores for the cylinders?---> injectors / fuel filter


With what you've thrown at the car already, the idle issue sounds like idle actuators to me, perhaps some slop in the ITBs.
 

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Discussion Starter #4
Ok. I’m willing to try injectors. But remember this goes from car barely drivable to 100% fine within each drive. If it was a sticky injector I’m trying to conceive how it can ‘fix itself’ then go bad again?

I did have a thought it could be some kind of idle air controller/aac?

When it first started the missfire was confined to low rpm (up to around 2500-3000). If you floored it once past 3,000 rpm it would clear up. It got worse over a few weeks until it triggered the ‘multiple missfire with cutoff’ mode. I’ve been trouble shooting it since.

I did have one other code once which was something like ‘coolant temp sensor value not possible’ or something like that.

I’m just at a loss to figure out what could:

A: make the car missfire so badly on multiple cylinders but;
B: clear up when car is up to temp and then car runs super strong.

Thanks for the ideas.

I don’t have itsta-d. I just have the ecs schwaben rebranded foxwell scanner. It’s pretty good. I can log any sensor value. I can do most adaptations.
 

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Does the E60 have an engine oil dipstick? If so, pull it out and see if it’s now overfilled and/or if it smells like gas. If you had 1 or more injectors stuck open it’s possible that the engine oil would be overfilled now due to the addition of gas which leaked past the piston rings and/or the oil would smell like gas.
 

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Does the E60 have an engine oil dipstick? If so, pull it out and see if it’s now overfilled and/or if it smells like gas. If you had 1 or more injectors stuck open it’s possible that the engine oil would be overfilled now due to the addition of gas which leaked past the piston rings and/or the oil would smell like gas.
The S85/65 have electronic dipsticks only.
 

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The S85/65 have electronic dipsticks only.


Bummer. Well, maybe check the oil level electronically and also take off the oil fill cap and sniff around a bit for a fuel smell. In my experience injectors are rarely the cause of any issue (I’m sure there’s those who will disagree) and it’s nice to test, not guess.
 

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Discussion Starter #8
Thanks for the idea. Oil level is checked regularly (both automatically by the car and triggered manually by me when oil is topped up). There’s no significant fuel in the oil. Plus if there was fuel in the oil it likely would have spun a bearing the other day when I took it up past 150mph when it was running sweetly.

What else do we have that could cause this kind of behavior?
 

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When it first started the missfire was confined to low rpm (up to around 2500-3000). If you floored it once past 3,000 rpm it would clear up. It got worse over a few weeks until it triggered the ‘multiple missfire with cutoff’ mode. I’ve been trouble shooting it since.

I did have one other code once which was something like ‘coolant temp sensor value not possible’ or something like that.

I’m just at a loss to figure out what could:

A: make the car missfire so badly on multiple cylinders but;
B: clear up when car is up to temp and then car runs super strong.

Thanks for the ideas.

I don’t have itsta-d. I just have the ecs schwaben rebranded foxwell scanner. It’s pretty good. I can log any sensor value. I can do most adaptations.

I have the exact problem, mid/low range rpm misfire, and mostly with light throttle. Much more when cold. I am very interested in what you or others come up with...thanks in advance. I had the VANOS solenoid replaced at the recommendation of the shop, and it may have helped a little, but not much.


Mike
 
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