Valve stem seals, misfire question

[bignasty27]

2009 BMW 4.8 135kms

Have always had a slight vibration at idle and "PUTT PUTT" out of the exhaust. Check engine light comes on and its MISFIRE cylinder 4. Great, finally get CEL and its going to fix my issue. Replace all ignition coils and plugs but "PUTT PUTT" remains. 24 hours later, MISFIRE cylinder 4. Take it back to the BMW INDY, runs it through a bunch of tests and numbers check out as normal, no vacuum leaks. Indy thinks it is related to the Valve stem seals. I do not get a bunch of smoke at idle or any other time. Yes, consumption was high but changed CVV and reduced consumption to the point where I am adding only 3 quarts per 5000km. I change my oil every 8000kms.
My questions is, can failing valve seals cause Misfires or is my Indy not trying hard enough to find the problem?
Based on the information on this forum, possible causes for my issue could be, fuel injector ( he claims he has never seen a bad fuel injector on this engine ), fuel filter ( claims there is not one on this model ) intake boot ( he did not do a smoke test ) and a couple of others that I have read.

I plan on taking it somewhere else for a second opinion.

Thanks!

[ard]

Does Indy have BMW specific computer system? Or is indy just looking at OBD codes?

A world of difference between the two..... IMO BMW sw lets you look at cylinder-to-cylinder timing issues, very useful to diagnose misfires that come and go. Also bank to bank air/fuel issues....

[bignasty27]

Just picked it up from Indy and yes he has BMW scanner.
Smoke test done, all good. Fuel pressure test, all good. All cylinders were tested and came back normal. No timing issues. He also tried another fuel injector on cylinder 4.Exterior of engine has no visual faults. He keeps going back to valve stems and oil burning as main cause.
They want to attack valvetronic now cause I mentioned the misfire happened after a cold start.
Not sure what my next move is. Misfire on cylinder 4 then on all cylinders code cleared so we will see.

[Pierce330]

I don't know which BMW indy you took your X to, but try Bimmersport or RMP. They are two of the most popular in the GTA. Depending on where you live, Stance Factory is also good. However, as Ard suggested, the scan tools make a world of a difference, this is why I suggested taking your X to one of the three mentioned above. I have never been disappointed by Bimmersport personally.

Best of luck...

[bignasty27]

Thanks!

I have an oil change booked with RMP and have spoken to them about my issue. Bought a parking sensor for my other X5 from this INDY and offered to diagnose my truck since I work next door. I already had ignition coils so he popped them in thinking it would fix the issue.

Forum has provided some great leads on the issue but so far it hasn't fixed my issue. Hopefully, someone can chip in with their thoughts but till then I'll keep searching and reading.

[A B Able Truck]

Originally Posted by bignasty27

Thanks!

I have an oil change booked with RMP and have spoken to them about my issue. Bought a parking sensor for my other X5 from this INDY and offered to diagnose my truck since I work next door. I already had ignition coils so he popped them in thinking it would fix the issue.

Forum has provided some great leads on the issue but so far it hasn't fixed my issue. Hopefully, someone can chip in with their thoughts but till then I'll keep searching and reading.

Info -
https://www.reddit.com/r/BMW/comment...our_n62_44_v8/

[Davidf]

I don't think valve stems seals will cause a misfire code (it did not on my '04 545i). My bet is on the wire connector at cylinder #4 coil. These connectors can be finicky and easy to believe you have it connected properly when it is not. Ensure the connector is fully seated and latched closed properly. Warning: Looks latched closed, but if you look close you can see it is not proper if that is the case...has happened to me more than once on several of my BMW's with similar connectors.

[bignasty27]

I am not 100% convinced that the valve seals would cause a misfire either.

Interested read about changing the gaskets AB ABLETRUCK and its seems like a cheap fix that couldn't hurt even if it didn't work.

I will check the wire connection on Cylinder 4.

The past Misfire was after a cold start.

Took it out for a ride last night and this morning and so far no misfire, it ran nicely. No hesitation or vibration at idle. RPMs hover around 700 but then drop to 500 when I turn off the Heating/Cooling system and then the vibration starts again and it feels like crap.

If unplug the MAF it runs nicely.

Going to do a throttle body service tonite with a buddy tonite to see if that helps.

[A B Able Truck]

I believe if you unplug the MAF it reverts back to throttle body operation with normal valve lift. The same way unplugging the VANOS solenoids do. I'll bet it's a carbon buildup issue. Run shet out of it with a can of Sea Foam in a full tank of fuel and see what happens.

[ard]

Originally Posted by bignasty27

If unplug the MAF it runs nicely.

Try cleaning the maf with maf cleaner, see if that helps- even a little bit. If it does, I would go ahead and replace the MAF.

Using stock air filters????