[Milan]

So I read through the misfiring thread. Here is the pertinent information:

08 335xi, 82k miles. HPFP and injectors replaced by the previous owner around 40k miles (warranty).

My car:
New plugs about 2k miles ago
New Delphi coil packs

Problem:
When my car is cold, sometimes (1/3 times) it will misfire really bad at idle, like after I turn the car on if I'm sitting in the parking spot. It will almost always go away if I turn the car off and restart it.

I have no issues driving around or once the car is warmed up.

According to the thread I should look into walnut blasting and new Vanos solenoids.

Any other ideas?

[Bavarian Tech]

Index of injectors ?

Generally a rough cold start of N54, is injector not VANOS related
BTW newest and greatest are Index of "12"

[Jklad]

I had an occasional rough idle on cold start for over a year, which would last for a few seconds - car would stumble hard, then revs would jump, then settle. Happened once every 5 cold starts. It was my hpfp, which had been replaced 50k miles ago.

[KeepRidingDirty]

This has injectors written all over it

[Jeff@TopGearSolutions]

Sounds like injectors if it happens on cold start.

Which cylinder is the misfire on, that is likely the injector that is leaking.

Or pull the plugs and find the plug the most fouled with fuel.

GL

[Milan]

Well today my car does not want to drive at all, overnighting 3 injectors from Rock Auto. Will the codes tell me which injector?

[924er]

Shaking/rough idle on cold starts are normal on n54 but should go away on idle. This is according to bmw.

[mweisdorfer]

I would have used Bosch coil packs. They are $179.00 on Amazon.

[07chupacabra]

This is pretty good to know, I've had a similar problem for about a year, only occurs for one or two start ups per year. And doesn't always happen on the coldest days.

How do you test injectors?

[KeepRidingDirty]

Start your engine, wait about 10 seconds, turn engine off. Pull spark plugs one at a time. Look for the plug thats either black (running rich) or fouled with gas (will be super clean and reak of gas). When my injector went it threw multiple codes and multiple misfires, it ran horribly and shot gas from the tail pipe.

[N0Chill 335i]

How has no one said get a WALNUT BLASTING yet? Your car has 80K miles on it. This service should have been done 20K miles ago... Do this and change your plugs at the same time and your car should be fine.

[07chupacabra]

^ Not a bad suggestion but I think considering the conditions in which he experiences the misfires would probably point towards injectors.

[N0Chill 335i]

Just saw that your plugs and coils are new, just get the walnut service.

[Andrewah05]

Dem Injectahs, i think carbon build up varies from car to car and should be the last too consider. My car had 80k miles when I did walnut blasting, I did it for good measure and indy said my car was in good shape, valves were no where near as bad as he thought they would be.

[mike@x-ph.com]

Sounds like injectors, are you getting any codes?

[07chupacabra]

Originally Posted by mike@x-ph.com

Sounds like injectors, are you getting any codes?

Mine has a pretty much the same issue, codes are 29CF and 2AAF.

[mike@x-ph.com]

Originally Posted by 07chupacabra

Mine has a pretty much the same issue, codes are 29CF and 2AAF.

2AAF is a fuel pump code, get it checked out.

[07chupacabra]

Originally Posted by mike@x-ph.com

2AAF is a fuel pump code, get it checked out.

Do injector's throw normally codes? It's weird how they both came on at the same time, and I smelt lots of gas through the exhaust.

The code is for fuel pump plausibility, could it be because the injector failed?

[mike@x-ph.com]

Originally Posted by 07chupacabra

Do injector's throw normally codes? It's weird how they both came on at the same time, and I smelt lots of gas through the exhaust.

The code is for fuel pump plausibility, could it be because the injector failed?

I dont remember getting any fuel pump codes when one of my injectors was going bad.

[Jeff@TopGearSolutions]

Injectors don't always throw codes when they leak cause they are just leaking a small amount overnight but not necessarily performing out of spec.

The only way to know which injector is to either pull the plugs and see which are fouled and/or if you have misfire codes on 1 particular cylinder than that is usually the faulty injector.

A walnut blasting on the intake valves should be done every 50K at a minimum. Getting it done every 35K wouldn't be a bad idea either as there is plenty of build up by then as well.