Multiple cylinder misfire codes
 

Hello all,
This is my first time posting.. I have a major issue. I've attached a photo of codes from my 08' X5 3.0si. I've replaced the following but still codes after reset.

Both Vanos Solenoids
Essentric shaft sensor
All 6 fuel Injectors
All 6 coil packs
All 6 spark plugs
Throttle housing
Cam position sensors
Disa valve
Oil pan gasket
Oil cap
Valve cover

I'm the second owner and purchased at 93k miles. Now has 112k miles.

It has been at the Indy shop for over 2 months now and im pretty ticked and at a loss.... any ideas or input would be greatly appreciated!

Thanks in advance,
Chrishttps://uploads.tapatalk-cdn.com/201...035782254a.jpg

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I had a mystery misfire issue on my s53 4.4 that turned out to be a self destructing A compressor that the knock sensors heard and reported. If you can’t feel the misfires in the way the car runs you could have false misfires, but if you can feel them something is truely up.

Have you done a compression and leak down test on the engine?

Thanks for some input. The only way I notice the misfire is at exhaust (putt putt putt) but other than at exhaust tips, car doesnt shake, shimmy, or sputter. Smooth as silk while driving. Also, if after first starting up, I give it some throttle while still in park, it will not shoot codes. Only reads misfires if I start and let it go thru its routine. I'd have to check and see if they did a leak down test... not sure what they have all done so far. As far as the list of stuff I replaced, I did all that myself. It's only after I was at a loss of what else it could be, that I took it into the indy shop.

The AC situation on my rig was mind blowing and only found after I gave up on the Indy and went to the dealer, which really was impressive.

That said on the compression / leak down side of things I was thinking that would a least confirm you don’t have something really bad going on like a head gasket failure etc and then it sets the stage for being worth more expiration.

One other thought, did the 3.0si experience any of the harness issues that the v8’s did?

What are the AFRs, fuel trims, etc??????

An air leak can lead to very rich or lean conditions ...causing misfires on all cyls.

When I see misfires on all cylinders I do NOT think plugs or coils.

A very rich condition will lead to the O2s getting overwhelmed with hydrocarbons, and cat conversion codes.....

Hmmm

:thumbup:I'm not sure of the fuel trim, I'll be getting more info on Monday. As far as a smoke test, already completed and no leaks.... It doesnt read misfire on all cylinders, but 4 of the 6. Also, it originally started with 2 cylinder misfire. It will however change from 4 cylinder MF to 2 cylinder MF to 3 cylinder MF.

I originally (at 2 cylinder mf) decided to do a tune up while replacing vanos solenoids and both CPS, figured I might as well just replace all coils, injectors and plugs.

Great thought Ard, certainly sounds like any high end fuel trims would promote a smoke test to see what’s leaking?

I'll get more info on Monday and update. Thank you both for your input. This vehicle has been nothing but a true headache since day one.

Smoke tests are almost useless on modern BMWs.


Look for a bit of cracked rubber or plastic...somewhere on/under the intake manifold...a little hose...an elbow...a fitting. Just enough to whack out the AFR, drive the DME to add fuel.


This causes misfires all over the place, that also move around. KEEP IN MIND how a DME 'reads' misfires: It looks at the acceleration of the crankshaft after each 'fire' and when it doenst detect the right amount of movement/accel, it say 'oh, must have missed. Now combine this with how the DME senses these signals...analog edge transitions, detection circuits, all sorts of jitter and variation. No wonder it shows up as weird patterns of misfires. A single dead coil? easy. usually cleanly detected.



My car has not been a headache since mile 1..... ;) just saying...