[WheelNut2]

Originally Posted by sabino56

Perhaps check DISAs to see if flap is loose? I’ve read they can break. I’ve no experience on whether a bad DISA could cause rough idle like yours.
Outside one is easy. You can get inside one off by removing alternator and reaching in from there.

DISAs are all good. Had a look at them when I redid the CCV system a couple months ago. Some people say they can break off and then get stuck in an intake runner causing all kinds of weirdness, but mine were fine. Well, they LOOKED fine at least. I'm assuming they are actually functioning properly, but maybe there is a test for them I need to do.

[WheelNut2]

Please delete. Double post error.

[crashoverride]

Check this thread out https://www.e90post.com/forums/showthread.php?t=863568

[crashoverride]

Here is a possible reason if you are still searching for a possible cause... clogged Catalytic filter... Do you feel like you have reduced power or do you smell rotten eggs

[WheelNut2]

Originally Posted by crashoverride

Here is a possible reason if you are still searching for a possible cause... clogged Catalytic filter... Do you feel like you have reduced power or do you smell rotten eggs

Exhaust smell is normal. Car seems to be putting out okay power. Sadly the 330i is pretty slow even when its running correctly. I'm still glad I didn't get a 335i though. I can't even figure this out- imagine a N54! Yikes hahaa.

Sorry about the glacial pace of updates here guys. I lost my K+DCAN cable somehow and I've just not had time to do anything to the car. I'm going to order a new cable and be back at it in August.

[nevan]

Originally Posted by sabino56

Perhaps check DISAs to see if flap is loose? I’ve read they can break. I’ve no experience on whether a bad DISA could cause rough idle like yours.
Outside one is easy. You can get inside one off by removing alternator and reaching in from there.

I've heard of this also in which the DISAs would work fine except in an idle state. The flap bounces slightly in an idle state. And you wouldn't be able to detect it unless you run the test using either INPA or ISTA+. I've also heard of a similar issue with the electronic throttle body.

OP, I have a similar issue. And those are my suspicions. I haven't had time to test them. But when I get around to it, I will probably check them first. And I also had a failing VANOS solenoid (exhaust side) also. As for mine, it did help calm the idle noticeably, but the rough idle is still persisted.

Anyhow keep us in the loop as I'm curious if my hunch is right (or not).

[WheelNut2]

Hey Folks, I'm back in the BMW problem solving game again. Wedding is done with now (it was great btw). I also somehow lost my K+DCAN cable when I went back home and used it on my step mother's E46. New one arrived a few days ago and I set it up tonight.

On Crashoverride's advice I checked out the Idle Fix thread link. I've already replaced the VANOS solenoids, and my coils are about 30,000km (20000mi) old, so that's two out of the three fixes in the thread. The third advice is to reset adaptations which I just did. The car idles pretty smooth now! BUT! There is a new code: 002CFB and 002D09. DME: Throttle adaptation value and DME: Throttle Valve. And as a lil Bavarian Bonus there is also 005E18 DSC: Engine Management Interface. The other issue I noticed, and this was mildly present before, is upon light throttle application in the driveway the car runs rough- the idle is okay, but at 5-10% throttle the RPM hunts between 1500-1800. With a bit more throttle the hunting stops. Also, the exhaust smells of fuel a bit, so I suspect its running a bit rich.

I will look into these more tomorrow and over the next few days. Perhaps ISTA can provide some sage advice for me as well.

Also, in response to Nevan: I removed the intake manifold months ago and inspected the DISAs. They seem to be in order. Solidly mounted, nothing loose, and nothing looking broken. I'm assuming they are working correctly, but I haven't run any test on them with ISTA/INPA. Do you know the test procedure for these units?

[toy4two]

Originally Posted by crashoverride

Wow you have fought the good fight and replaced more than most would've. Sounds like the dealership would've actually saved you money on this one.

I've had similar issue. It came down to at least one bad ignition coil (how did they test..??). I would for sure replace them all at once.

Does the rough idle go away when you turn the AC off as there is a known problem and fix for that type of rough idle.

Or I have no experience on this guess but the idle control valve can get dirt stuck in it and can be often blown out with air.

I look forward to your future updates as I follow with interest your efforts.

my 328i (flashed DME to 330i avoided DISA 3SIM) did the exact same idle bouncing since they day I bought it with 80k miles. BMW dealer said it was normal and nothing they would fix.

I found in INPA an RPM adjustment, you crank it up to the maximum in INPA like 1000 and it changes the RPM +100. Car has been stable since then I believe its a leak somewhere I'm too lazy to find nor care about spening more money on.

I did new plug, coils, checked ecentric shaft sensor visually, it had a new valve cover gasket job done by dealer before I bought it and I did the oil filter housing gasket. New tensioner and belt. Cleaned the 2 little vanos filters and use only fresh Castrol Euro 5W-30. Nothing changed the idle, cranked it up 100RPM and its smooth now, leads me to believe air leak somewhere, spraying starter fluid around didn't locate it.

[nicholas6706]

Hey thanks for sharing all this. I'm facing very similar problems with a minor rough idle on my 330i without any codes on ista. I've replaced disas, both o2 sensors, maf, eccentric shaft sensor, pcv system, coils and plugs. Unplugging maf also doesn't fix my problem.

I've noticed my bank 2 long term fuel trims are consistently higher than bank 1 peaking at ~+12% occasionally. Meanwhile, bank 1 is +/- 3%. Have you logged your fuel trims for a longer drive? I'm considering replacing bank 2 injectors with another used set, but it seems like n52 injector problems are extremely rare.

[crashoverride]

I just created a thread on this... I was talking to a mechanic he said they often solve the rough startup by checking that the high school lube techs didn't throw away a stem that extends into the oil filter. It often gets thrown away during an oil change. Without the bowl of oil can easily drain deprive the oil pressurized bits that need oil pressure during startup.

Unscrew filter cap check middle of oil filter.

[WheelNut2]

That is a good tip! In my case I've already had a look. That plug in the oil filter housing is present and accounted for.

[WheelNut2]

Howdy fellas,

Still digging around on this. Something I noticed recently while looking at INPA things is that at idle the engine is mildly stable running, but if I increase the throttle to 3-8% it really stumbles badly and run VERY rough. If I increase the throttle and rpm then it runs more evenly.

The Valvetronic VVT adaptation seems quite high as well. Any thoughts?

[LanDzia]

Hey man, have you ever done any software update on your car?
I've just done mine few days ago as it was bone stock late 2005 built, specifically to the latest I-level integration update which is essentially update to the whole car (except CCC).
Since this update my rough idle is kind of gone. The rpm needle is steady and doesn't jump anymore, however the car still vibrates a little.
I'll be looking further into it but I suspect it might be old engine mounts.

As you know I had no codes much like yourself and all usual suspects were done (except disa valves) and no air leaks confirmed by a smoke test.

If you haven't done update, I suggest to search for BMW specialists In your area and see if they do integration level updates. Avoid main dealer as they have asked me 3x the price of what I've paid.
You can even so it yourself, but this full update takes many hours, so good idea to hook up battery on charger just in case.

Good luck

[WheelNut2]

Thanks for that info LanDzia. I have the car scheduled in for a software update on October 11th. I looked into doing it myself, but the risk of bricking the car and cost of a power supply to keep the voltage up during the update is too much for me to stomach. I'm really hoping that the software update helps. If it doesn't I think that would just leave something like vanos adjusters as the culprit, in which case I would probably just sell the car rather than dump the time and money into the engine to fix that issue.

[WheelNut2]

Software integration level has been upped to the most recent version in all modules. NO DIFFERENCE. F***

Edit: It ran a bit better on the way home…the jury is still out though. I’ll know for sure after I put a few hundred kilometres on it.

The shop reckons the next likely culprit would be the vanos adjusters. Either a bad bolt or a fully bad adjuster unit. Debating between trying to unload the car and actually fixing the thing. I can certainly do the work and get the replaced, but do I really want to? And what if that still doesn't get the thing running 100%? The car is driveable as is and its pretty good, but perfection is the dream. I've dropped $3800 in maintenance and parts into this thing in one year now. I'm thinking I should/could have just bought a brand new PHEV 3er because it would have been the same expense and I wouldn't have had to spend hours and hours and hours fooling around with researching issues and working on the car. Anyways, I'm very frustrated. At least the price of gas is down and the car runs well at wide open throttle. I need a couple pulls to red line to clear out the anger.

[WheelNut2]

I did the accessory belt off test last night. Made no difference to how the car ran. Maybe rougher than ever actually. So, all the pulleys should be good.

I'm a bit stumped on how to actually diagnose this issue WITHOUT using the parts canon on it again. Anyone know what to look at to understand if the Vanos adjuster units are actually functioning properly or not?

[WheelNut2]

Originally Posted by dokotm

I've gone through the entire conversation, but I couldn't find any mention of you checking the fuel pressure (although I might have overlooked it). The fuel pressure should be at 75 psi, and you'll require a fuel pressure gauge to perform the test.

I checked fuel pressure. All good: 75psi. Its buried in the thread somewhere. Oil pressure is also good.

[crashoverride]

As tempting as it is to try this or that as every part on our car is suspect and could be the culprit and can be easily justified as needing.

Sometimes it's best to just take it to the dealership. It's rare for them to just start needlessly swapping out parts. They will warrant whatever is done and it kind of reminds me of the story of the engineer with the hammer.


A giant ship’s engine failed. The ship’s owners tried one ‘professional’ after another but none of them could figure out how to fix the broken engine.

Then they brought in a man who had been fixing ships since he was young.
He carried a large bag of tools with him and when he arrived immediately went to work. He inspected the engine very carefully, top to bottom.

Two of the ship’s owners were there watching this man, hoping he would know what to do. After looking things over, the old man reached into his bag and pulled out a small hammer. He gently tapped something. Instantly, the engine lurched into life. He carefully put his hammer away and the engine was fixed!!!

A week later, the owners received an invoice from the old man for $10,000.

What?! the owners exclaimed. “He hardly did anything..!!!”.

So they wrote to the man; “Please send us an itemised invoice.”

The man sent an invoice that read:

Tapping with a hammer………………….. $2.00

Knowing where to tap…………………….. $9,998.00

Effort is important but experience and knowing where to direct that effort makes all the difference.

[NZE90]

Originally Posted by WheelNut2

I did the accessory belt off test last night. Made no difference to how the car ran. Maybe rougher than ever actually. So, all the pulleys should be good.

I'm a bit stumped on how to actually diagnose this issue WITHOUT using the parts canon on it again. Anyone know what to look at to understand if the Vanos adjuster units are actually functioning properly or not?

You can do a test on the VANOS adjusters with ISTA. In fact
you can do automatic tests on a LOT of components with ISTA. Have you done any guided troubleshooting with ISTA before? It pretty much does it all for you when the engine is running, you just have to know how to activate the test.

[crashoverride]

I think I saw you tried Cam Shaft positioning sensors any change for that part swapping out...???

[WheelNut2]

Originally Posted by NZE90

You can do a test on the VANOS adjusters with ISTA. In fact
you can do automatic tests on a LOT of components with ISTA. Have you done any guided troubleshooting with ISTA before? It pretty much does it all for you when the engine is running, you just have to know how to activate the test.

I have not done any such tests with ISTA. I will look up how to do such tests!

[WheelNut2]

Originally Posted by crashoverride

I think I saw you tried Cam Shaft positioning sensors any change for that part swapping out...???

I only checked the ESS for oil contamination. I haven't had a look at the cam position sensors at all.

Any suggestions for diagnosing ESS or CPS at all? Is there a specific parameter in ISTA I can use to investigate them? Should I get an oscilloscope, back pin them and check out the wave form? I really don't want to just fire the parts cannon at this problem.