car dies when braking?

Tried researching this a bit on here as well as via google but can't seem to find anything that directly relates to my issue, so;

this has happened 3 days in a row now, I start to slow down and by the time i'm still my engine has already stopped running. That's the gist of it. Before I get into the specifics that I managed to notice so far, some background info on the car.

04 325xi, 5-speed. Purchased a few months ago, put about a 1000 miles on it so far. I can't remember off the top of my head exactly but the car has about 90k miles on it. Runs and drives fine, apart from this damned thing.

First time this happened I was coming to a stop at a red light and I believe it happened when I took the car out of 2nd gear, but I had to turn a bit to avoid a pothole and realized my power steering wasn't working which then lead me to realize my gas pedal wasn't functioning as you'd expect it to as my car shut off.
Second time this happened was under similar circumstances but while the engine was still on, I noticed the battery light go on, then check engine light, then oil.
Third time, similar story.

The car starts right up right after this happens without any hesitation. It doesn't stutter as if I stalled out or anything of that sort. I don't have any sort of warning light on at a constant basis, the car runs and drives great.
It's almost as if fuel just gets cut off but I don't think that this is the case.
As I'm writing this, I'm thinking maybe a battery terminal came loose? I'll check on that in the morning but again, I don't think that's so as I wouldn't be able to start my car right away, right?

Also, not sure if this relates to anything, but when I first start my car in the morning and it's fairly cold and I give it a bit of gas in neutral the revs actually go down and eventually it stalls unless I give it a good quick tap. I mean I usually wait until the car is warmed up to drive it but I never had the same issue with my old car.

Fuel pump. Do a search as its not an XI specific issue but I'm guessing its failing and is an easy fix and common failure.

And isn't the definition of "breaking" something being broken? So if your car dies while its "breaking" isn't it supposed to? Or did you mean "braking"?

Just giving you some crap, OP.

Agreed on the fuel pump diagnosis. Replace the filter while you're at it.

To confirm the issue, check the codes stored in the system. If the engine really stalled out, there will be codes to verify that and point to the problem.

intake cam sensor?

Originally Posted by VALMONT

intake cam sensor?

+1. I was going to say exhaust cam sensor.

Scan codes.

Originally Posted by miweber929

Fuel pump. Do a search as its not an XI specific issue but I'm guessing its failing and is an easy fix and common failure.

And isn't the definition of "breaking" something being broken? So if your car dies while its "breaking" isn't it supposed to? Or did you mean "braking"?

Just giving you some crap, OP.

haha whoops, gotta go back to grade school!
and I figured it wasn't Xi specific but since it's an XI I figured I'd post here. I'll get the codes read tomorrow but would the cam sensor cause the car to shut off? I mean I could see it causing issues with startup but cause the car to shut off completely?
Will report back tomorrow, thanks for the quick replies!

well, got the codes read (finally). Came back with P0171, P0174, P1512, and P1515.
From what I managed to find after a quick search the first two codes definitely have something to do with the DISA valve while the third may be related as well. The last code apparently is not a valid BMW code and would require a better diagnostic tool than what AutoZone has to offer which my friend happens to have but of course, he lost the BMW key. So, any pointers?
Should I change the DISA valve? I mean my check engine light isn't on, these are all stored codes.

I've never seen a DISA specific code, but pull it off and inspect it per the videos and diys on here. Check intake boots for leaks before buying a DISA.

I'd throw a fuel filter at the car and and consider the fuel pump diagnosis again too.

yeah I'd check it now but seems we have a blizzard here on our hands out of nowhere haha. already an inch of snow after an hour at most.
looks like it's time to check out that 4wd

well went to start the car today in the 20 degree weather we're having. Started right up but the idle started bouncing for maybe 10 seconds until it finally stalled. Waited a bit, started up again, idle still bounced for a good minute or so but eventually evened out and was fine without stalling again. Also check engine came up. I'm in school now so hopefully I'll get a chance to stop by AutoZone before work.

Also, I saw that the P0171 code combined with the P0174 can be the CCV? Is it something I should check? Hoorah for more problems -_-

System too lean means you're either not delivering adequate fuel pressure/volume or you are getting unmetered air in your engine. The options are to check your intake boot, DISA o-ring, and intake air temp sensor o-ring for damage and to replace your fuel filter and pump. If these don't solve your problems, then look into more expensive solutions like a faulty MAF sensor or faulty fuel injectors (unlikely because it's the entire engine).

My money is on the fuel filter and pump. A broken intake boot doesn't come and go like this and will throw a code fairly quick.

Also, I'm guessing the code you read today will be the same as before.

yeah the guy at autozone told me the set of codes is likely to be my MAF, I needed a MAF quick when I first got the car and the only available one which was cheap was one from a 328, not sure if that could be the reason for this? I just did a quick search and read that it could cause a light and that it would cause it to lag in performance, but not to the extent of the issues I'm having, right?

Suggest you read the first 2 links below in my signature.

2 comments - CCV lower oil return line and DISA.

You should also read this thread - http://forum.e46fanatics.com/showthr...ghlight=report

I would hold off on all sensor replacements at this point.

Tell me more about the MAF change:
Where did you get the replacement?
About how much did you pay for the replacement?
Do you still have your original MAF?

Still have the original MAF, pretty sure it failed completely as the idle would just bounce and eventually stall out. The new MAF seemed to have fixed that problem.
I got the 328 MAF from my buddy as he had it laying around the shop. He bought it from carpart or somewhere similar. Either way, it was a used part but like I said, it fixed my problem.

Also, I'll give a good read to those posts tomorrow when I have the time.

So I just got home from school, 15 degrees here today. Needles to say the car just stalled out right after I started it until I finally started revving it. Drove fine after that except for shutting off on the highway -_-
Luckily for me it was right as I was switching to 5th so I had the clutch pressed in and just started the car again as I was rolling.

On my way back, the car basically refused to move. The clutch caught on fine, but as soon as I started to give it a little bit of gas the RPMs went down and the car stalled out. Therefore, I was had to ride the clutch like no other revving it to about 1500-1800 before I could release the clutch. This was a ton of fun especially as I was stuck in rush hour traffic for about 40 minutes.

Needless to say, seems like my clutch is gonna be next on my to do list.
Peachy.

Originally Posted by CK325

well, got the codes read (finally). Came back with P0171, P0174, P1512, and P1515.

Ok so I have been doing some thinking and I retract my fuel pump theory.

P1512 points to a faulty idle actuator which would mean that your idle valve is either broken, stuck, or both. Clean this thing out and it may go back to normal. If it is stuck open, it would explain why you are stalling out at idle and when you push the clutch in (engine goes to idle). It is allowing more air into the engine than fuel is being injected therefore giving you the lean condition on both banks. The ICV works post MAF so the air isn't being properly metered. If cleaning doesn't work, get a new one either from the dealership or a junkyard.

P1515 points to a throttle position sensor fault. This may be related to a faulty ICV so I'd start there and see where it takes you before dealing with this.

Maybe crack in the lower intake boot...very common...clean the icv...often needed. Use techron.

I'd forget the clutch being an issue. You actually described the symptoms I had at the end of my 30 mile drive with a bad alternator...running on battery only. At the end, I had to have the gas floored to have the clutch engage...the FP was pumping on its last legs I guess.

So don't forget to check your battery too. If things aren't getting enough power, you'd have issues, just like I had.

Read voltage when off and on both. You had a red battery light on first in one instance you noticed.
Check the electrical system just for grins.

I meant after all this clutch riding
Lower intake boot seems fine, ICV makes sense, will do all this over the weekend when I have the chance and I'll report back.

Thanks for all your help!

If you are replacing the DISA, before you do look at this solutiuon. http://forum.e46fanatics.com/showthread.php?t=923291 I did this and it's better than a new DISA and will cost about 1/2 the price.

CK325,
My wife came home one day complaining about our 2003 325xi stalling everytime she came to a stop light. Your symptoms and codes are very similar to the codes I pulled after test driving the car. My problem was due to the DISA/intake air adjuster had failed. I removed it and could visually see that the internal flap was no-longer connected and therefore was not adjusting intake air flow. Obviously yours could be something else but it sounds exactly like mine. After the install the car runs better than ever. I've only had it for 1 year but it now seems to have more power and accelerate better.

F16Driver
03 325XI
Fredericksburg VA