04 330Ci 6M 65k

It dips, sometimes. Never stalled on ME, but the previous owner said it did it once. He had something (dont remember, simple) replaced and seemed to go away.

Have you had your DME software updated? That might help, It was said on this forum that it can help rough idle.

 

DME software updated as stated above. Like I mention, that only helps the M54 engines, and in my opinion only masks the problem.

The vanos solenoids don't fail. That's not it.

Replace your pre-cat O2 sensors. They have a lifespan of 100k miles. After that they degrade causing increased fuel consumption and degraded performance. Be sure to use Bosch OEM sensors.

Put back your OEM air filter box and hoses. Use only OEM Mann filters.
CAI setups can screw up the MAF and permanently damage it.
K&N air filters are oiled and foul the MAF.
Re-clean the MAF.

Try disconnecting the MAF. If the problems completely resolve it MIGHT be the MAF. Disconnecting the MAF causes the DME to use default maps which err on enriching the air/fuel mix. This can cover up a performance problem.

Are the CPS sensors OEM? As you know aftermarket sensors don't work.

My guess is it's the MAF.

Raj, thanks for the comments, I was hoping you'd lend your expertise. The O2's are something I'm considering for sure. I just don't think they'd contribute that much to loss of power. Also, don't think it has anything to do with the air filter, I had this issue both before and after I had my CAI. The MAF has been cleaned no less than 3 times, and I am lean on the oil when I clean the K&N. I've tried disconnecting the MAF, no change.

The CPS sensors are both OEM, no change after installing those.

My fuel efficiency is fine. I'll pull down 34 mpg on highway and 23 in city, combined is usually around 26 or 27.

What makes you so sure the VANOS solenoids don't fail? Seems like that is the most elegant solution to this problem in that I notice a low end loss of power...isn't that where the VANOS is really supposed to shine? In your research of the seals, did you ever test the solenoid? Is there a way to test it?

My guess is ICV, MAF or O2 sensor in that order.

ICV is clean and works fine, MAF is clean. If O2's are bad, no codes yet, but definitely going to look at replacing soon.

 

The vanos solenoids don't fail. That's not it.

Replace your pre-cat O2 sensors. They have a lifespan of 100k miles. After that they degrade causing increased fuel consumption and degraded performance. Be sure to use Bosch OEM sensors.

Put back your OEM air filter box and hoses. Use only OEM Mann filters.
CAI setups can screw up the MAF and permanently damage it.
K&N air filters are oiled and foul the MAF.
Re-clean the MAF.

Try disconnecting the MAF. If the problems completely resolve it MIGHT be the MAF. Disconnecting the MAF causes the DME to use default maps which err on enriching the air/fuel mix. This can cover up a performance problem.

Are the CPS sensors OEM? As you know aftermarket sensors don't work.

My guess is it's the MAF.

 

I have the same exact problem except I have a 2001 330xi Auto. Its a pain in the a$$ and I hope some members can point us in a better direction to solve this problem.

 

My guess is ICV, MAF or O2 sensor in that order.

 

Yea, I have it. 2000 328i with ~74,000 miles. I have had the car since brand new. I don't remember the car doing this until it got some miles on it. Like past 50,000 miles. The first I noticed it was when my intake camshaft sensor starting acting up. When those things start to go it is very obvious. Can't drive it at all. Won't run. Engine dies. I thought this non cold idle dip/stall was a precursor to the bad intake CPS, but it wasn't. Fixed the obvious stalling of a bad CPS though. Probably just a coincidence.

It is the most annoying problem ever. It irritates me to no end. And kinda dangerous because if you are getting ready to turn a corner and clutch in you have to be mindfull that it doesn't stall on you because you lose power steering, etc. I basically have to pop the clutch.

I have done the VANOS seals and replaced both CPS which threw codes. Replaced nothing else because everything I could think of over the years as a possible culprit I found someone online that did that and it didn't fix it.

The key is to finding out what BMW did to mask the problem with a software update in the M54 engines.

 

i am having the same problem, someone please help!

 

The MAF cleaner is safer to use. I suspect it evaporates faster and leaves less residue.
Electrical/electronic contact cleaners seem to work fine. You do need to wait longer for the MAF to dry.

I've seen cases of owners with your symptom that was caused by a failing MAF. But the problem could also be something else.
I've seen cases where a CAI permanently damaged a MAF.
I've seen cases where a K&N filter screwed up a MAF.

Disconnecting the MAF is a good test, but you need the OEM air system to be sure it's a valid test.
A failing MAF can throw a code but often doesn't.
I wouldn't think a dyno test with a lambda sensor would shed clear light.

So this problem existed when you bought the car. Do you have any history of when it happened and what it coincided with?

 

I'll try cleaning the MAF with MAF cleaner this week.

I bought this car with 75,000 miles on it back in 2006. I have always felt that it was not as "quick" off the line as it should be...it doesn't have that instant acceleration when you hit the gas until you are in the upper rev ranges. I remember test driving a lower mileage 328 back when I was looking and it felt as though there was an on/off switch in that car, just instant power when I punched the gas (it was stock). Similarly, my brother's 330ci feels the same way. Now I realize that he obviously has a bigger engine, but I know the 328 is missing torque somewhere...just doesn't feel as snappy as it should.

Unfortunately, I have no history with this car...something I plan to avoid in the future. It looked as though the previous owner took pretty good care of it, and I know I've taken care of it since I've owned it.

I am 99% sure the idle dipping / stalling / weaker than expected performance are all related. I just need to figure out why. Perhaps I will try to find a new MAF. I guess I could put it in and if it didn't work, return it? :shhh:

 

Same issue except my car doesn't actually stall. I resolved the cold idle issue by replacing the VANOS seals but the warm idle is still a problem. I have performed almost all the same steps as you have except:
Clean MAF/throttle body/DISA
Shark Injector/DME Updates
Replace CCV and oil filter housing gasket

I will start by cleaning the MAF/throttle body/DISA to see if that helps.

 

I didn't read all the responses, but I've had this issue. The car stalled on me once. Other times the rev's go all nutty and i need to put it in gear or give it gas to make it stop.

My indy said that it was the Oil Separator (cracked?). It was replaced (1.5 yrs ago) and after that everything was peachy.

UNTIL...

The other day i was waiting at stop light and my car growls all of a sudden. Turns out the rev's are bouncing around again. It is getting warmer here now, im hoping the car just needs to get adjusted to higher humidity and temps. I'll be keeping an eye on it.

 

mine does the same exact thing

m54b25
01 325i sedan, 5mt

i have replaced both CPS sensors, VANOS seals, CCV, cleaned MAF/ICV/DISA, i don't have a CAI, i have an OEM air filter, fuel filter was changed (problems happened before it anyway), and yes.. only happens in warmer high humidity weather. I'm also thinking its running very rich.

so tired of the bouncy idle and the lack of torque

 

Hi guys

This excatly happens to me but it does not have to be in the cold. Excatly when the engine is warm it occurs. I first did not have this problem with my car when i first bought it. However I understood it was lacking a lot of power, therefore i took it to a garage where he told me the mass air flow sensor was disconnected therefore I replaced the mass air flow sensor (assuming the old 1 which was disconnected was fault) and connected it back up.

The car gained A LOT of power back but this idling problem occured. When the MAF sensor was disconnected the problem did not occur but again lacked power. I got idle sensor all cleaned but I have not heard of the O2 sensor...WHERE IS THAT?

Fuel Filter was changed
Spark Plugs
Oi and filter (which makes another big difference to the preformance)
Lamba Sensor changed
Battery Changed

Its a pain in to be honest, espcially when your in a traffic jam it could occur at any point and the car just seems to lack complete power.

My car is a 318ci (2.0l) N42

Regards

 

update:

my car threw out the code for the camshaft position a sensor.

replaced it today and is now running good.

i will test it for a few days and see if the problem comes back

check to see if your crankshaft sensor is working properly

 

Probably a separate issue for you. The CPS can definitely cause poor idling. I've replaced both of mine with OEM sensors, no dice...underlying problem remains.

 

2001 325ci 135k

replaced vanos seals, fuel pump & filter, maf cleaner, and just some fuel injector cleaner. thats really it i think. still have the problem.

it doesn't stall after i start the car up. i turn the car on, and pump the gas slightly (once or twice) to get it going, then its fine. if i dont pump the gas, then it will die. but once i start driving, it never stalls.

 

as of now what codes are your car throwing out?

keep us updated, good luck!

 

I wish my car threw a code, then I could fix it. No codes stored or active.

 

I started having this issue after installing my Supercharger and it's intermittent. Its more pronounced now in warmer weather. I think it's probably due to small vacuum leak or one of my hoses going from CCV to intake pipe on SC is bit kinked.

But before I put on SC, I noticed that my gas mileage has gone down and I lost low end torque.
I changed vanos seals, fuel filter, spark plugs but it didn't help. I think I am gonna change my pre-cat O2 sensors as Rajae said and see if that helps.

No codes are registered and CEL is not on. I haven't tried cleaning MAF sensor but did clean ICV when I changed CCV. It wasn't really dirty to start with.

 

I cleaned my MAF again, no change. Also ran some concentrated Techron cleaner through the car, but no difference. Still stumped.

 

My car has been having unexplained stalling for awhile now and the other day I removed the ICV, TB, DISA, and MAF, which I cleaned and put back (Everything looked good unfortunately so they are ruled out). The next step may be having my computer software upgraded. Does anyone know how much that will cost?

 

I had that stalling issue and also idle surging up and down for about a year. My mechanic fixed it by cleaning icv and TB. That was maybe two years ago. I started noticing the beginning of the surging again about 6 months ago...and when I concluded a long diy, the surging is gone.

Although I replaced a lot (I'll do the list) I think it was the icv or TB cleaning.

That said, I also did lots of other stuff, like replace the TB gasket and elbow...the grommet for the icv...the 0-ring for the disa (cleaned also). This same trip I also did ccv and oil filter housing gasket, but doubt they're related to the surging...as they weren't done before when the surge first appeared.

Now, when I cleaned icv, I sprayed a whole can in it (if not more) and kept turning the thing until I felt a nice solid clang of the valve...initially, it was pretty stuck, and although it freed up pretty well pretty soon, I just kept on spraying coz I didn't want to get in there again. So, folks with this problem, I'm not saying it is icv and cleaning, but just that it might be that depending on how thoroughly you cleaned it...and it might also be that if you didn't replace gaskets or o-rings (I think the icv grommet is a pretty stable thing so doubt that would fail...but had the part, put it in anyway).

My mechanic did say that if it went bad again, it would be worth replacing...though now that I can do it myself, prolly won't be buying a new one.

Also, coz I'm ocd, anytime I unplug an electrical connection, I clean it really well and let it dry thoroughly before plugging back in. BTW, with MAF cleaning, I also used practically the entire can...just saying. Although I don't want anyone to go in again based just on my word, I also don't want anyone unnecessarily buying new parts that they probably don't need.

If you can live with near stall for a while and 'work around it,' then soon, I'm sure your car will want something new in that neighborhood anyway and you can get in and try cleaning more and I hope that works for you.

 

^^thanks for your feedback, and glad that worked for you. Unfortunately, I don't think any of those are causing my issues. I've cleaned that ICV twice, it works fine, and I've replaced the CCV, so have had the throttle body out and cleaned it. All gaskets have been replaced at this point.

I'm still hunting for now...

 

Sorry, I wonder whether the icv could actually be bad and not just dirty. I know the dealer wouldn't clean it...would just replace it...so something to consider. I think your TB is same as mine...on a cable, right...so that takes that out of the equation I think.

As I'm recalling, mine seemed more likely to stall (back when it did) when it was raining...so I wonder if the high humidity might be a factor...and I'm throwing in with those that wonder about your K & N and MAF...I know you cleaned it again...but I'm wondering if maybe in humid conditions, the vapor is clogging the oiled filter more than it would a paper one and that might be attenuating your issue.

Anyway, it's not an uncommon problem, and I know mine was and now isn't...and I know what I did...so if not MAF/air filter related, I'm sorry, but I think I'd revisit the one thing that seems to be controlling idle...assuming all the basics are taken care of...and it sounds like you've more than taken care of them...only other thing is the cleaning of connections...which had been open while you're working on car...maybe getting dripped on...I'm sure most mechanics don't do that...but since I'm not one, I do!

Know this doesn't help! Sorry!

Doug

 

How did you check for vac. leaks? I had this EXACT problem on my 328i and then again on my 330i. Both cars were completely fixed when I located and fixed vac. leaks. The 330i had a leak at the intake to DISA valve connection. If you have removed the DISA, my guess is that it's leaking right there! If you have not already done so, hit that joint with some carb cleaner or starting fluid while the engine is running. If the idle dips when you spray the joint, you have a leak. FWIW, my M3 was doing THE SAME THING TOO! I cleaned the MAF very well with MAF cleaner and then (and this is important), reset the adaptations. The M3 seems MUCH better now. It's too soon to say it's "fixed" but so far so good. When I cleaned the MAF, there was 0 change in the way the car ran. After I reset the adaptations, it stalled a few times the first time I drove it. After that first trip, the car has run flawlessly. It has picked up the lower end that it had lost and the idle has quit bouncing around.

Just make sure you have eliminated the nearly free fixes first (vac. leaks and MAF cleaned). Also....I had cleaned the MAF in the past too with no results. I had to pull the sensor from the tube (on the M3, not sure how it's setup on the 328) to really flush it well from all angles.

 

Are you talking about the throttle adaptation procedure where you turn the key to on for ten seconds, then off for ten seconds, then go drive like a bat out of hades for a while? Been there, done that.

 

01 330ci 141,000 auto.
most commonly on hot humid days, when say.....i go stoplight to stoplight within a short distance, so on the gas till about 2-4k then on the brakes, when the rpms come down they get to about 400 then level out. Also if i rev it in park and take my foot off the gas quickly it drops to about 400 then levels out like you said previously.
i have on and off p0717/p0713 (lean) codes.

 

Vac. leak!

 

I see a lot of guys mentioning vacuum leaks. Honestly, I like this assessment as well, since it seems a stumble may be caused by a leak, especially when humidity changes. I just can't find a leak if there is one. I suppose I can change the DISA gasket. That cost $2 and takes all of 5 minutes to do. The ICV gasket has already been changed and that thing has been cleaned numerous times, it is very smooth. I don't know where else to check for vacuum leaks. Does anyone know a place that can test for it? Will the dealer?

Others have indicated it is my CAI. I am 100% convinced that is not it, this problem existed prior to install of that part. I also did a lot of research and am completely unconvinced "over oiling" impacts the MAF...if I was overoiling, which I'm not. I find no traces on the MAF and I've cleaned that beeetch several times with MAF cleaner.

I don't know if I mentioned this symptom previously, but if I rev at a stop and dump the clutch, the car bogs down on me, doesn't have that "HOLY $HIT, HERE WE GO!" punch like it should. Anyway, I'll try replacing the DISA gasket, see if that doesn't help.

NicB.

 

I had some of the same issues and here's a summary of my experience Post 24. Looking over your original post:
1) how many of the parts you listed are OEM? It could be that the parts you have installed are faulted.
2) have you tried seafoam? comparing what you've done to what i've done that seems to be the only difference on top of the additional items you've replaced.

2001 330i 5 spd MT, over 120k on the clock. good luck

 

All parts are OEM...I always go OEM.

Have not tried seafoam...actually pretty scared of that stuff and not sure I will ever try it. I hear it can jack up your engine pretty good.

Nic,

That adaptations I am referring to are the ones for the fuel trim. Basically the computer uses data from the o2 sensors to determine if the car is running rich or lean and then adjust to optimum from the base maps. That's an over simplified explanation but valid none the less. The adaptations can cover for a rather large vac. leak but because vac. is not a constant, the adaptation don't "cover" for it correctly all the time. On the one hand, the car will run remarkably well with a vac. leak. On the other hand, you get all sorts of weird things like idle control issues, loss of power, CEL codes (sometimes too rich, sometimes too lean) etc. The best way to check the entire system is to do a "smoke test". Basically they use a machine to blow smoke under just a little pressure into the intake and then watch to see if the smoke leaks out anywhere. Another way is to have the engine idling and then shoot all the joints you can see with something like carb. cleaner or starting fluid. The idle will change if that stuff gets sucked in. That's not ideal because it can be dangerous (use very short bursts) and you can only check the spots you can see. I could not find a place that could do a smoke test close by so I used the starting fluid "test" and I did locate my leak that way. The DISA on the 330i that I had did not have a seperate gasket but some silicone gasket maker worked great in sealing it up. I had the same issues as you and sealing that leak plus a leaking intake elbow allowed the car to run like new until I sold it (sad.....but I did replace it with an M3 so.......).

Good luck.

Todd

Makes sense...I already have the DISA gasket on order (since I have a 328i, it has the gasket). I'll pick that up tomorrow and put it in Saturday, but don't expect that to be the issue. I will also check around and see if there is a place that does smoke tests.

I'll report back once I put in the DISA gasket.

 

I have the same issues you describe I have replaced ICV, plugs, ect.. nothing has solved the issue I agree the K&N intake is not the issue. As I had the problem and stalling before the intake. I think it is a vacuum leak. I am not throwing any codes therefore I don't believe its O2 sensors. I have been plagued with oil system leaks since I owned the car. First the Valve cover gasket then the ccv which in hind sight probably caused the valve cover gasket to blow, and I have recently changed the gasket that mounts the oil filter housing to the block because of a leak there, I have noticed improved performance and believe I was loosing pressure to the Vanos system due to the bad gasket. I have thrown lean on bank 2 codes from time to time but none consistently which makes me think there is still a vacuum leak However still experience this surging as you described this weekend I plan on working on the disa valve for vacuum leaks I think I have a leak around the shaft of the butterfly valve. will report back.

Hope to fix this problem and help you find yours.

 

If you were losing enough pressure at that leakto make a difference, you would have had oil POURING out anytime the engine was running....and I mean POURING out! Not saying you did not have that but wow....that would have to be a huge leak.

 

Changed the DISA gasket yesterday, no discernable difference.

 

I'm thinking of other things I did that might be different from what you did...going after essentially the same things as I did.

One, again, I really cleaned all elect. contacts on both sides really well...I sprayed them, blew out with compressed air, sprayed again...made sure they were facing down and dried well (like hours) before reassembling everything.

Also, there's a vac. hose that goes into the rubber boot just behind MAF (hard plastic hose that comes from the corner with the fuses under the hood...think it's fuel related...anyway, when I pulled that out, the grommet at end of hose seemed dicey going into its boot elbow, so I added just a touch of rtv on it to seal it well.

I did new gasket on TB and new grommet on icv as well as on the disa (sorry that wasn't it for you!).

With ccv replacement, I replaced the 6 o-rings in that plastic piece that has one of the ccv hoses click into in two places. I'd removed that piece (not sure I needed to, but I did.

I also sprayed wd40 or something up into the TB cable (guess you don't have one...sorry).

Since it's humidity related, I'm going back to thinking about the MAF and your CAI and second the suggestion to go back to good ole oe...at least for a test. Finally, maybe find a local fanatic who'd let you borrow his MAF to see whether it's not an issue with cleaning, but whether it's just gone south for whatever reason.

Sorry again for your woes...I did not like having that issue...and sorry if at some point you need to go back in again...but maybe some of the easier/more accessible things I did were the difference that would make a difference to you.