[mattthecoxcomb]

Hello,

I am a long-time reader, first-time poster.

I have an '06 325i MT with 96,000 miles. The N52b30 engine is retrofitted with the three-stage manifold and reflashed with a 330 tune. CCV and all associated hoses were replaced at time of the manifold swap last August.

The problem: Over the last week and half I encountered a rough running issue. Idle fluctuates between 740-500 RPM. Acceleration has stutter/vibration at different throttle positions/loads. SES light comes on intermittently, most often at startup after the car has sat for a day or so. Each time the codes are the same: misfire, cylinders 3 and 4. SES does not appear to come on when the car is warm (usually). Idle problem is also intermittent--some times it seems much worse than others. I cannot seem to correlate it to driving conditions or other outside factors.

What I have tried:
1) I cleaned the VANOS solenoids, that appeared to have no effect.
2) I replaced all spark plugs and ignition coils (plugs were done as routine maintenance at ~95,000 miles, ignition coils done after the start of current issue), no effect.
3) I replaced fuel injectors in cylinders 3 and 4 (upon removal, o-rings on old injectors visibly perished), no effect.
4) Eccentric shaft sensor inspected at plug--appears OK.

Oddly, after doing the injectors, I cleared the codes and let the car sit overnight. When I started it the next day, the start/idle was a little rough but it felt better than before. No SES light. When I drove the car a second time later that same day, SES light and idle problem returned.

Also, in the interest of thoroughness: a trusted professional shop replaced the valve cover gasket at 95,000 miles due to an oil leak over exhaust manifolds (I also had them do spark plugs at this time). I replaced the outer DISA around 8,000 miles ago due to power loss.

Every time I get the SES the codes show misfires in the same two cylinders. However, the misfire does not appear to be occurring at all times. Also, if this were a DISA problem or vacuum leak I would expect it to effect all cylinders rather than simply the same two.

I got a Foxwell code reader of Amazon yesterday and tinkered with some of the diagnostic modes--including shutting off injectors in cylinders 3 and 4. When I did this, the idle was much worse. So I don't think the misfire is occurring at all times (which I would think rules out bent valves or the like).

The only thing I can think of at this point is swapping in new spark plugs in 3 and 4, but the ones in those cylinders have only run for 1,000 miles and they were fine for the first 800 miles or so. Can spark plugs become ungapped in that amount of time if they were almost out of spec at the time they were installed?

New plugs and coil packs are both Bosch as I've had reliable service with them on my e46. New fuel injectors are re-manufactured GB.

Any feedback is welcome and appreciated. Pretty exasperated at this point! Thank you!

[mattthecoxcomb]

Anyone?

[hassmaschine]

Any codes? Oil in the plug wells?

[NCSUPack24]

Yeah, I’d be double checking their work. Pull the coils for 3 and 4 and check for oil like haas said. If there’s pooling in there, that’s your problem.

The valve cover gasket is a pain in the ass, and there’s a chance it got pinched or moved during install.

As for the gapping question, I really doubt it.

[mattthecoxcomb]

Thanks for responses. The codes are:

002FA3 - DME: No coding
P03000 - Multiple Misfires
P03030 - Misfire cylinder 3
P03040 - Misfire cylinder 4

These codes appear with each SES. I am able to clear all but 002FA3. It comes back almopst instantly after clearing codes but I have read that this code is pretty common and doesn't really relate to rough running? Any thoughts?

[hassmaschine]

2FA3 you can just ignore.

[mattthecoxcomb]

Hassmachine, any thoughts on what could be the problem? I have read a lot of your stuff and know you are one of the N52 gurus...

[hassmaschine]

Like I said, check for oil in the plug wells of cylinders #3 and #4. you could also try swapping coils with another cylinder that doesn't have a misfire, and see if the codes follow it. Just because a coil is new doesn't mean it's good..

[mattthecoxcomb]

Following up:

I took it to a local indy specialist because I didn't have time to continue diagnosing myself. Turns out the inner DISA flap broke up and was sucked into the manifold occluding the ports to cylinders 3 and 4.

PRELIMINARY examination suggests it wasn't actually ingested into the cylinders and no catastrophic damage. I won't know definitively until it's back together but I am cautiously optimistic.

As I mentioned above I noticed a power drop months ago that, in hindsight, was probably related to the inner DISA failing. I replaced the outer DISA at that time because it's much easier to do and supposedly is the more common failure. Replacing the outer one didn't really improve things and, because I hadn't run the car for very long with the three-stage manifold, I think I just thought this was how the car should normally feel. It goes to show that it's worth going the extra mile to fully investigate when you think something might be off.

Many thanks to Kassel Performance of York, PA for speedily diagnosing and repairing for a reasonable price. You can check out their IG for a photo of the broken flap pieces perched inside the intake ports. I hope this is helpful to others going forward.

[hassmaschine]

Nice! Bummer about the flap but at least it's not worse. I doubt it did any damage.

Funny, I wonder if the O2 feedback loop is fast enough that it can tell individual cylinders apart.. there are only 3 on each bank so it's plausible.

[bsmoov]

I'm surprised it didn't throw a disa related code...

[mattthecoxcomb]

Unfortunately, the DISAs do not throw codes when they fail in this manner. I believe a number of other forum members have encountered this. I even tested mine with my Foxwell code reader and they indicated proper function--probably the actuator shaft was turning normally inside the housing but the flap itself had separated from the shaft.

Short of periodic removal and visual inspection, a loss of performance might be the best indicator that this is happening. This of course is based only on my individual experience with one car...

To anyone upgrading to a three-stage manifold: I'd recommend replacing the inner DISA (if not both) at the time of installation unless you know the provenance (age) of the DISAs that came with your manifold. Or buy a manifold without the DISAs and buy the DISAs separately. It significantly adds to the cost but I wish I had done this. Mine appeared to be in good shape but I really have no verifiable way of knowing how old they were or how many miles they had.

[Ozzie335i]

Twofold great news. That it was fixed at a reasonable cost. And that you found an honest garage.

[mattthecoxcomb]

So, it turns out it was the OUTER DISA which failed. All is good and I avoided major engine damage. Car is back up and running, again thanks to the team at Kassel. But that this happened is curious, since the part was less than one year old. It was a VAICO V20-2260. Supposedly the VAICO part is actually superior to the BMW part because it uses a metal actuator shaft.

I purchased it on October 12, 2018 from Bavarian Autosport and it is supposed to have a two-year warranty. I was going to submit a warranty claim but I just learned that Bavarian Autosport has CLOSED. I have tried contacting VAICO directly but their website contact page is not allowing me to submit. I have emailed their general email address but everything is in German and I have doubts about their responsiveness. We will see what happens. This is a weird issue to run into.

[hassmaschine]

Actually I believe there have been numerous failures with "new" third party disa valves. Meanwhile, my original 13 year old, 150k mile disas are ticking along just fine.

While expensive, it seems sticking to original BMW is best. They will wear out eventually but it will likely take 10+ years and 100k+ miles.

[mattthecoxcomb]

So, a new development. Over the last several weeks I have been noticing a fluttering sound coming from the engine compartment upon hard acceleration. I also noticed a grinding sound coming from the compartment upon shutting off the car. Sometimes the grind would occur only once, sometimes it would occur several times, each lasting maybe one second. Both sounds occurred intermittently. After a while I decided to try to determine where it was coming from, so I opened the hood before shutting the car off after a normal drive, shut the car off, and ran to the front to put my ear to the engine. Sure enough, the grinding sound was coming from the outer DISA valve. A "tactile" test confirmed this.

Yesterday I returned home from a 1,600 mile road trip. The car performed great. This morning as I started it up to run some last minute holiday errands, it immediately went into a very rough idle with a loud clicking sound coming from the engine bay (but no SES light). Given that I had been keeping my eyes on the outer DISA, I immediately set to work in pulling it to check. Sure enough, the flap is completely gone.

I want to point out that the newest DISA was ALSO a VAICO V20-2260. I mention this because it has been less than 16 months and 12,000 miles since installation. This obviously supports hassmachine's observation about third party DISAs being junk. Such a short interval between catastrophic failures is completely unacceptable.

Luckily this did not occur somewhere in rural South Carolina where I had been traveling. Also, fortunate that the same shop that replaced the DISA last year (Kassel Performance in York, PA) has offered to cover the labor cost of replacing the DISA and retrieving the disintegrated flap from the manifold. They will be talking to their supplier about the warranty on the part itself. As before, I am very concerned that parts were ingested by the engine--fingers are crossed that this is actually rare in the N52.

Regardless of the part warranty, I will be going with an original BMW DISA this time. I will follow up once I know more.

Happy holidays, everyone!