[bsmoov]

2006 325xi 6MT

Getting a cylinder 5 misfire. Moved coils around and still misfire on cylinder 5. Intermittently the codes read cylinder 4, 5, and 6 misfires.

I have:

1.) Replaced all spark plugs (same codes)
2.) Replaced all coils (same codes)
3.) Cleaned vanos solenoids (same codes)
4.) Replaced the fuel injectors on cylinders 4,5,6 (same codes)

Still misfire In cylinder 5. Intermittent misfire in 4,5,6

Coil connectors look and are connected fine.
Fuel injector connectors look and are connected fine.

Not sure how to move forward. No other codes…

[Daaaaaaaan]

How does the engine run/car drive? Horribly or mostly okay?

Did the issue happen suddenly or gradually?

Compression test would be the next move usually. Maybe someone will chime in with another step.

Are you getting power to the coil?

[bsmoov]

Engine is like it’s running on 5 cylinders.

Shaking, ticking, and misfiring.

[Daaaaaaaan]

and the other questions?

[bsmoov]

Suddenly. I had a service engine soon light for like a week, but it ran perfectly so I kept driving it and was going to diagnose on the weekend, but the light went away by itself. Couple of weeks later, light came back on and it was an apparent misfire.

I’m not sure if I’m getting power to the coil. Is there any way I can check it with a multimeter? I don’t have the tools in the vid you attached.

[Daaaaaaaan]

There's probably guides online.

SES light may or may not have been related. Hard to tell without knowing what the codes were at that time. A $20 OBD reader in everyone's glove box pays for itself many times.

When I got the symptoms of your issue, it was a broken exhaust valve spring. Happened at idle, not a money shift. Car was fine one second, and running super rough the next. Bizarre failure mode really. Did what you did, checking coils and plugs, but problem didn't move. Diagnosed by compression test before taking things apart. 5 cylinders good compression, 1 cylinder held no pressure at all. I'm unsure if a borescope inspection could help, or just go straight to compression test if spark is good.

Was ~CAD$2300 to dig into the engine and replace the $25 spring. Luckily valves didn't drop. Pistons were all good. Had to choose between replacing all the springs for $25 each or keep the existing unfailed ones. Decided to just replace the broken one and the rest have been good for several years and still going. Turning a brick into a functional vehicle again was worth the cost once I took it to a competent mechanic.

At least I got a new valve cover gasket out of it!

Don't take it to the dealership. You'd think they'd be knowledgeable about diagnosing the problem with their supposed skills and abilities, or at least read my note about swapping coils and plugs around but the problem didn't move but for a $240 diag fee, they told me to replace the plugs and coils. Idiots.

Here's to hoping yours is a frayed wire and a $1 fix.

[bsmoov]

When your car was fine one second on idle then the symptoms happened, what were your codes? Same as mine?

[Daaaaaaaan]

Originally Posted by bsmoov

When your car was fine one second on idle then the symptoms happened, what were your codes? Same as mine?

Pretty much. Wasn't the same cylinder as you, but same idea: one cylinder consistently coded misfire. Sometimes the adjacent ones would also code a misfire. I'd clear the codes and try fixes, but the bad cyl would always code a misfire and others might register later. That's expected because everything becomes imbalanced from the consistently messed up cylinder. Your Cylinder 4 and 6 misfires are probably because of the cyl 5 problem, but there's probably nothing wrong with your cyl4 and 6.

[bsmoov]

The exhaust spring, is that diy-able?

Are there any guides out there?

[Daaaaaaaan]

Originally Posted by bsmoov

The exhaust spring, is that diy-able?

Are there any guides out there?

Not DIY-able for my skills/abilities. You don't have to remove the engine itself, but you are taking a good chunk of the top off beyond just the valve cover.

But we're not certain this is your problem.

[NZE90]

Could be a broken Disa valve. Broken bits often find their way into the intake ports and cause misfires. There was one on here recently.

[NZE90]

https://www.e90post.com/forums/showthread.php?t=1510929

[bsmoov]

Welp. I guess I’ll pull off my intake manifold tomorrow to check.

[NZE90]

Does your 325i have DISAs? I just remembered some US models don't have them. Maybe 328i doesn't?

[bsmoov]

Yeah I have a 3 stage intake manifold on it.

[bsmoov]

So I pulled my intake manifold and no broken disa flaps to my disappointment…

Both disas pulled and are fully intact and firm with no free play. Manifold runners are clean.

Valves look good all except cylinder 5 (where my misfire is). It clean and no obstructions, but for some reason it has fuel in it. Not a lot, but noticeable that the other cylinders don’t have or have a lot less visable fuel.

Coil wiring looks good.

I was really hoping after all this work it would be a broken disa, but I just wasted a lot of time pulling my intake manifold for no reason.

[bsmoov]

@Daaaaaaaan

The coil wiring has power. I tested it with a multimeter and it showed continuity in parallel with the other wiring.

[NZE90]

The only other thing i can think of is try unplugging the eccentric shaft sensor, then starting the car. This will put the valvetronic into full lift mode and rule out a worn intermediate lever/eccentric shaft.

If that doesn't do anything then it might be time for a compression test.

[NZE90]

Did you say there is a ticking noise as well? If so it could also be a broken intermediate lever spring

[bsmoov]

Yes there is a ticking noise as well.

If I remove the ess and start the car what are the 2 possible outcomes?

[NZE90]

It will either run smooth or not. Worn eccentric shaft is pretty rare TBH but you have to go through all these things as a process of elimination.

If it is ticking from around cyl 5 it is likely it has a mechanical issue. Do you have a stethoscope to try and pin point where the noise is coming from?

[bsmoov]

Ok. How about the fuel in the valve of cylinder 5? I did notice while looking for disa pieces that there was a pool of fuel there and also I did notice the bottom of the injector in that valve dripped a drop of fuel too.

Are injectors supposed to drip like that? It was a newly replaced injector too.