car stalling and very sluggish
 

Hello everyone,

I have a 2001 X5 3.0L. Two weeks ago my car stalled while driving in a parking lot at very low speed. I restarted it and had a check engine light. When I tried to accelerate the car gently (from stop) it would stall on me. When I accelerated harder the rpms would drop suddenly but the car would not stall. When driving the car felt like it weighed 10 tonnes and was having trouble accelerating. The next morning, I started it up and it ran fine.

The problem happened again a few days later. After reading a few threads I decided to change the Mass Airflow Filter. I thought it worked but it happened again yesterday. It seems that starting the car on a hot day, when the engine is already warm causes this - although it could be a coincidence, but this has been the case every single time.

I ran carsoft (which I just bought yesterday) and it said there is a problem with my oxygen sensor post catalytic. From what I have read, this would not cause these problems.

My guess is that there is a problem with the air/fuel mixture. Does anyone have any ideas what else I can check?

Thanks again.

I assume you meant Mass Air Flow Sensor (to my knowledge there is no Mass Air Filter).

One thing you might try is to disconnect the MAF. Doing so causes the system to use fail-safe parameters for the air/fuel mixture. If the stalling / stumbling disappears it would indicate a problem with the MAF (unlikely since you just replaced it) or a leak in the intake post MAF. You may have created an air leak where the intake boot connects to the engine when you replaced the MAF.

Another possibility would be the intake cam position sensor dropping signal, and it doesn't throw a code for it right away but will after a few days.

Yes - you are right. I replaced the Mass Airflow Sensor - not the filter.

The next time it happens I will try disconnecting it and see what happens. Should I have replaced the rubber gasket that sits on the MAF?

Unless it showed some kind of excessive wear or was torn I don't think it would be necessary.

Ok, I just drove it all day and ran carsoft. Here is what I get:

228 Mixture Deviation: bank 2
Cylinder 4-6

65 Camshaft angle pulse generator

I'm guessing the camshaft position sensor needs replacement. Would that also cause the Mixture deviation error? Or could something else be causing this problem?

Also where is the camshaft angle pulse generator?

Depends on which cam sensor it is talking about... The exhaust cam position sensor is on the left side of the front of the head and the intake cam position sensor is on the intake side of the front of the head, right by the vanos oil line and solenoid.

Thanks for the reply.

It doesn't look like there is any way to determine which one it is based on that error code. Is it possible that this error is not even caused by any of these sensors? Something like a vacuum leak?

The camshaft angle pulse generator fault is definitely from a cam position sensor... but without a better fault description on which it is you don't know which. Odds are from the symptoms it is the intake cam sensor, but as easy as the exhaust cam sensor is to change it isn't a bad idea to just change both of them anyways.

Thank you very much. I'll replace it tomorrow and report on how it goes.

Ok, so I went to the mechanic today to have the sensor replaced.

He ran it through his scanner and it told him that the intake sensor was broken (which is what I told him). He also told me that the oxygen sensors needed replacement. I told him not to touch them until he changed the camshaft sensor first and then run the diag again. So he changed the sensor, ran it again and everything was clear - including the O2 sensors. Charged me $65 for labour which I thought was fair and nothing to run the scan.

Thanks again for all your help.

Good to hear it is all done with. And I do take some satisfaction from guessing it right on. ;)

My 01 3.0 started doing this exact same thing. Sometimes it is great tons of power, then it is a dog, and sometimes it will randomly stall like when Im slowing to turn. I will keep all updated on progress but from my research it sounds like a camshaft position sensor.

Bosch makes crappy CPSs

car stalling
 

did the cps fix the problem.(how is it running?)

I don't know yet, I posted my previous message last night. next step is to clear all codes and see what pops up then order the sensors. I plan on replacing both the exhaust and intake CPS's if the codes say so.

i'd check the MAF sensor first. give it a quick clean - 10 min job & see how you go.

OK I cleared the codes and it did it again last night, cranked over 3 times longer than normal to start, then was DOG SLOW. Couple hours later ran an errand and was back to normal. The SES light did not trip back on through this ordeal. Any ideas?

Sounds like the intake cam sensor for sure... the DME uses it's signal for the cam timing/ignition timing etc. so if it doesn't see the signal it kinda makes up default signals from the crank sensor and defaults the VANOS system to not advance the cam timing so it will be slooow... It kinda does the same thing if it loses crank sensor signal by defaulting off the cam sensors, but the cam sensors fail 20 times more often than the crank sensor. I'm actually surprised it didn't throw a code with the long crank/slow drive really.

If you pull the cam sensor out and look at it the old style sensor that has the failure problem is stepped down in diameter just after the o-ring while the new updated BMW cam sensors are thick all the way through.

OK I cleaned the MAF and it didn't do anything. Problem continues. On the good side, I lost the P0171 and P0174 codes after replacing my CCV and hoses. P0344 popped up which confirms Weasel's suspicion about camshaft position sensors... I will go ahead and replace both of them. Interestingly enough, I got another code- P0505- which is related to idle. When I changed my CCV I also thoroughly soaked the ICV and it rotates great. Idle is perfect. Could the random crappy running from the camshaft sensor have triggered the P0505 code??

When you cleaned out the idle valve did you use lots of lube, or parts cleaner? I ask because I always use parts cleaner to dissolve the carbon deposits, but no more than a quick shot of spray lube after cleaned just to protect it a bit. If you soaked it down heavily with penetrating lube it may have seeped into the motor causing some faults... Just a thought.

No i didn't lubricate it. I just soaked it in carb and choke cleaner. The little spinny thing was stuck solid, after soaking it clinked back and forth nicely.
Maybe I will replace the cps then clear the codes and see if it comes back.

Sounds like a good plan of action to me.

OK, I replaced both exhaust and intake camshaft position sensors and while at it replaced my PS reservoir and hose to the pump. Started the car up and drove to AZ (car ran sluggish) and had the codes cleared. It drove amazing! So snappy and fresh. I was happy... until the next day I started it from cold, and SES popped on and it was sluggish again! I can stop it, restart, and it's much better, but not to where it should be.
Im going to have the codes run again today and see what they say. Any ideas?

It could be fuel starvation as well, you might want to change your fuel filter which is cheaper than the sensors. Stalling and having trouble accelerating will definitively happen with a dirty fuel filter.

Have about 40 miles on a new one already.

This is definitely sensor related. I turn the car off and back on and the problem is gone, and it is completely sporadic.

Paging Weasel!

I was waiting to see what codes popped up... Maybe double check that the vanos solenoid is plugged in really good since it seems to be doing something slightly different now. If it has a flaky connection in that plug it might not activate properly and put vanos in default.

Im on a work trip now but will check first thing, and have codes run and report back asap.

OK Weasel, I ran the codes, and bingo its P0344 cam position sensor again. I've replace both of them! WTF.

Now that is odd..... I've never seen that code come back after replacing the faulty cam sensors with OEM units. Hopefully it is something simple, I'd double check that the sensor is sitting fully flush, maybe pull in out again just to peek in the hole with a mirror to make sure there isn't any gunk in there. If it wasn't under the intake I'd say check for proper 5v supply and ground at the plug, but it gets power straight from the DME so odds are it isn't the problem unless wires got damaged somewhere, but not likely.

OK Weasel, I took out the intake camshaft position again, when I got to it I noticed that there was a little gap between the sensor and the block:

http://i271.photobucket.com/albums/j...00807-1334.jpg

I took it out, and peeked inside:

http://i271.photobucket.com/albums/j...00807-1341.jpg

Looks ok. I cleaned the cavity and reinserted the O-ring, then reinstalled the sensor.

I also was able to get readings (with key in ON position) at the connection where the cps plugs in, and from passenger to drivers side got 12V, 5V, and ground at the three terminals.

Does this help at all? Was thinking maybe I got a bad sensor? It was not a BMW original sensor but it was brand new off ebay.

Most likely the gap was the cause of the problem, it is a pretty close tolerance in there. If not I have seen many people have trouble with the ebay sensors as well.

Well the gap was there even after I took it out, reinserted the o ring and secured it again. So there's nothing I can do about that gap. The symptoms have changed from before... Now it is sluggish right when you start it from cold. After warmed up you can turn it off and back on and it is a lot better. Before, it always ran good from cold, then after restarting hot it would be sluggish. Also, now the stalling problem is gone. In addition to how aggravatingly DOG SLOW this X5 is going, it gets HORRIBLE gas mileage. I went to detroit today and when running badly I was getting 18 mpg at 80 mph. After stopping and restarting, I got 20. Before this problem ever started, I got 23 at 80. On top of this being incredibly annoying and expensive, it is very embarrasing! Should the next step be dish out 100 bucks for an OEM cps? Would hate to do that if its not the problem! Thanks for the help...

Bimmerboy12---you need to compensate Weasel by a night out in NOLA for his input. I got a headache just reading through all of this. The only thing I've ever bought off ebay for my '01 is a cabin filter--other than that when it comes to parts always go OEM. Time to take it to an indy sounds like.

If you think thats a lot you should cruise through the E30 forums. This is child's play.:D
I visit NO twice a year and would be thrilled to meet up with Weasel and buy him compensatory beverages.:thumbup:
And why the hell would I take it to an Indy when I have far more reliable and knowledgeable information right here at my fingertips??? ;)

You said you are embarrassed, annoyed and it's getting expensive. You've exhausted all options to get it riding normal-- it's time for another set of eyes (ie an Indy). No sense sweating it---life is too short.

heehee Im a long way from exhausting all options buddy.. I think I've got this one, but thanks for your concern!
Now quit filling the thread with posts and let us get back to solving my issues :nanana:

You may want to use some RTV sparingly to plug the gap, as you already know air gaps are bad when it comes to engines.

I can't recall if you are getting codes or not nor do I know if you have the 6 or 8 cylinder engine. If you're getting codes and you have the 8 cylinder engine I would recommend you swap the two CPS's and see if the codes change. If they do that would be a good sign the CPS is bad. If not I would look elsewhere.

Please ignore if this has already been done. It's been a few since I read the entire thread and I can't recall all the diagnostic work that's been done.

You are on here for advice. My advice is your fix has not worked. At some point if it's not working then you will need another set of eyes. The longer you drive it with issues the more chance something else can go wrong. But good luck with your "options".

Yes getting P0344 on my 01 3.0. gap won't leak air since it is very tight with the o ring, the body of the sensor is not perfectly co-axial with the opening in the head. We're talking MAYBE a degree. Check out the picture above.
Thanks for the help!

If you've checked the fitment then I doubt it's the gap. At this point if you still suspect the CPS then buying an OEM part may be your next step. Or, as others have advised, taking it to a shop. I'm not sure how much an OEM CPS costs but if it's not too much then what would be the harm? The worst is you've spent money for something that didn't solve the problem. But now you've got a spare :D Or maybe you can resell it to someone. From what I've read over the past few months this is a regular service part which people seem to need.

yup my same thoughts exactly. I already ordered an OEM BMW cps for 90 bucks. The ebay one was 31 bucks so not like Im getting screwed here. Well let you all know the outcome this thursday or friday!

I did the same with a MAF. I ended up paying $120 for an aftermarket one. It ended up solving the problem for a few weeks and then the vehicle began to exhibit MAF problems. I borrowed an OEM MAF from my mechanic and drove the vehicle for a couple of weeks. The problem was gone and I just paid for the part.

Ok I missed a bit apparently as I was on a short overnight vacation/trip, but it sounds like the cheap ebay sensor was causing problems and it should actually be fixed with the OEM part now ordered.

Looking back at the pics, it kinda looks like the housing is warped on the ebay sensor causing the gap/not letting it sit flush.

OK update: replaced Ebay sensor with OEM sensor from bavauto... problems are completely gone, codes are gone, runs better than ever! The moral of the story- cheaper is not always better...

Congratulations on solving the problem. I learned the same lesson with my MAF.

Congratulations! Question: Did the gap that you had with the old sensor disappear as well?

Nope, that gap was exactly the same with the OEM sensor. So that wasn't the problem.