Car stalling in traffic - P0173 error code

ualla · Post by **ualla** » Mon 10 Mar, 2014 12:16

Hi guys, I'm wondering whether you'd be able to help me figure out an issue I've had with my Z3.

Yesterday I was very happy as it was lovely and sunny so I managed to go for a good drive with the top down so I decided to head south, towards the sea. On my way there, I got stuck in a little traffic and when I stopped in the queue my car just turned off. I could see the ECU trying to keep the car alive by revving automatically, and a few times it succeeded, but the car turned off 3 times in total on my way south.

The engine was in perfect temperature, it had plenty of fuel and it turned off with the clutch pressed. It turned on straight away, no trouble there, so I'm not really sure what could have caused this. After about 30 miles without having to stop, I didn't get that issue any more.

I've thought it could be the spark plugs or even dirty fuel tank. I've just received my OBDII reader so will give that a go tonight to see if I can spot any anomaly, but I might even give a fuel additive a go to try and clean the system.

bertiejaffa · Post by **bertiejaffa** » Mon 10 Mar, 2014 13:57

Sounds similar to an issue I have on my 2.0l when I am stuck in stationary traffic for ages. (6/7th paragraph http://www.zroadster.net/forum/viewtopi ... 32&t=39871) Does this look the same? - Ignore the misfire, that was resolved due to a coil

With mine if it cuts out it will usaully only do it once, and will fire up perfectly immediately and then is generally fine afterwards although the oil light flickers for me while I am still crawling (going off and staying off when I get moving again). I saw a thread somewhere that it can be linked to poor oil.

Del · Post by **Del** » Mon 10 Mar, 2014 14:52

Sounds like a typical sensor issue e.g. inlet cam sensor - but you need to plug the car into a error code reader to properly interrogate the ECU.

ualla · Post by **ualla** » Tue 11 Mar, 2014 00:15

Thanks for the replies guys

First of all, love the mods you're making Bert, especially the headlights!

Now back to the problem I've come across. And yes, it is very very similar.

I have managed to use my OBD reader on the car and in fact it does throw up an engine error code: P0173. It is a fuel trim malfunction according to OBDCarDoctor, specifically on bank 2 where I seem to have a negative 3 value. Now, I don't really know what that means in practice, but after having read online it is either the MAF sensor which would need replacing or it is a vacuum leak.

Does anybody know a knowledgeable Z3 mechanic in the London area? Someone that knows these machines like the back of their hand?

bertiejaffa · Post by **bertiejaffa** » Tue 11 Mar, 2014 09:06

Cheers for the comments fella...

Someone else mentioned MAF sensor as a suggestion on mine as well, I think there is a few threads on it if you wanted to try it yourself including some YouTube videos. It seemed a bit out of my capability to be honest to do myself but then again I am in no way a mechanic (hoping to attempt my first ever oil change in a few weeks

). You might think differently though and be willing to have a go yourself?

There's a thread at the minute running about garage recommendations in North London http://www.zroadster.net/forum/viewtopi ... 02#p372702

Hope it solves the issue, can you keep us informed - I am going to be selling my silver z3 in the next couple of months and would ideally like to get this sorted if I can before I sell it to ensure it is in pristine condition for the next owner.

Mike Fishwick · Post by **Mike Fishwick** » Tue 11 Mar, 2014 09:09

Your problem sounds more like a sticky idle control valve than a fuel trim error - check the simple and cheap things first, before blinding yourself with science!

Take the ICV off and clean it out - and also check for air leaks in the inlet system.

bertiejaffa · Post by **bertiejaffa** » Tue 11 Mar, 2014 09:27

Good comments Mike

Forgot to mention, with mine, the revs at idle are always constant (circa 600rpm) even when in stationary traffic, however after being in traffic for 10-15 mins that's when the oil light starts to flicker. Revs remain stationary but sometimes (not every traffic jam) the revs will start to drop then raise a couple of times by themselves before it stalls. As mentioned, it restarts immediately with no problems and then continues with the flickering oil light for the rest of the duration that I am stuck in traffic -usually without stalling again.

Just to add as well, I am going to replace my throttle cable this week hopefully. When I do set off (anytime) there is stickiness between idle and 1500 rpm. I am used to it and it doesn't bother me but everyone else who drives the car hates it - I don't think this is related to it but I might just raise the idle rpm up a little to 700 when I do it

ualla · Post by **ualla** » Tue 11 Mar, 2014 10:13

Thanks to both for the input, very much appreciated. Thanks also for the link to the mechanic thread!

The reason I was thinking there might be a leak in hose, is that over the weekend I noticed that my car emitted white smoke for quite a while, but I put that down to my paranoia. Having read a bit online, I think it might just be related as it could be caused by a lean air/fuel mixture (which would also explain the -3 value on the second bank, wouldn't it?). I also have a very bumpy shift from first to second gear, which I also read could be related.

I checked my idle yesterday and on a cold engine, as soon as I turned it on, it was stable around 779rpm.

I'm really tending towards a leak in the inlet system, although I have been proved wrong on here before

Del · Post by **Del** » Tue 11 Mar, 2014 10:14

Always difficult to pinpoint these generic error code problems. Unlike some cars, the MAF sensor on these BMWs are not directly on the throttle intake and so there is always a risk of a vacuum leak between the MAF sensor and throttle, letting in “unmetered air” and causing a lean mixture. Split rubber pipes are therefore a common problem and probably a good place to check first. These issues are normally more noticeable when the car is being started from cold when a richer mixture is required.

In my experience, if these problems only occur when the car has been well and truly warmed up on a longer journey, it is likely to be something else e.g. the MAF sensor or a problem with the crank ventilation system. Apart from the MAF sensor, problems with other sensors generally tend to show up as a specific error code for that sensor.

cosmosblack · Post by **cosmosblack** » Tue 11 Mar, 2014 11:40

i would put money on it being the crank case breather valve, mine was exactly the same, perfect driving and then just cut out when I stopped, this got gradually worse, always fired up straight after, cost me about £50 for the apart and about a days work, but car sounds perfect now no cutting out she is purring

bertiejaffa · Post by **bertiejaffa** » Tue 11 Mar, 2014 16:36

cosmosblack wrote:i would put money on it being the crank case breather valve, mine was exactly the same, perfect driving and then just cut out when I stopped, this got gradually worse, always fired up straight after, cost me about £50 for the apart and about a days work, but car sounds perfect now no cutting out she is purring

Did you do this yourself? A day sounds like it was tricky to do? Is there any guides?

cosmosblack · Post by **cosmosblack** » Tue 11 Mar, 2014 22:09

yep i did it myself, it was a little tricky followed some guides on the you tube, not the easiest thing i have done, but very rewarding, dont think it would be cheap though if a garage did this, i had never done anything like this before so dont be put off,

cosmosblack · Post by **cosmosblack** » Tue 11 Mar, 2014 22:13

just add to this i had never done an oil change on a car and i did this so please dont be put off, it looks scary when you have all the parts out but take your time and it can be done

bertiejaffa · Post by **bertiejaffa** » Tue 11 Mar, 2014 22:32

cheers - just watching you tube - did you need any special tools (like the socket set extension arm)

cosmosblack · Post by **cosmosblack** » Wed 12 Mar, 2014 09:29

Hi, no I didn't need any special tools, just a few sockets, I have read on other forums that people have put they have changed the part even when they have got no symptoms, and it has made a fast improvement,

ualla · Post by **ualla** » Thu 13 Mar, 2014 15:49

Thanks for all the info!

This weekend I'll inspect the intake boot, although I am aware that if I do not manage to spot anything, it doesn't mean that it isn't cracked. I wish I could do the smoke test, but I don't have the tools to do a DIY one.

@cosmosblack, do you by any chance remember the part number for the crank case breather valve?

Thanks!

ualla · Post by **ualla** » Sat 15 Mar, 2014 15:10

I think I may have found the problem. Today and went to my car and ran the diagnostics again, but this time I didn't get any error strangely enough.

I decided to inspect the hoses and boots, and I found out that 1 of the 2 boots that are connected to each other (the one closest to the engine) has some kind of duct tape.

Here's a video of what I mean: https://vimeo.com/89182035

I've had a look on realoem, but apparently I'm rubbish at trying to find parts. Would anyone know the actual part number for to have a look online so I can replace it?

Thanks!

Del · Post by **Del** » Sun 16 Mar, 2014 22:24

is it this part?
http://www.ebay.co.uk/itm/BMW-E46-3-Ser ... 4897.l4276

Mike Fishwick · Post by **Mike Fishwick** » Mon 17 Mar, 2014 08:53

As I suggested ages ago - look for the simple things first!

The £14 Ebay intake bellows does not look particularly cheap - I wold have thought that you could walk into most dealers, and walk out with a new one for about the same money. How much are they from a dealer or German & Swedish?

ualla · Post by **ualla** » Mon 17 Mar, 2014 09:30

@Del: thanks, that is indeed the part, the lower boot. I've also managed to find the part number on realoem.

@Mike: I'm just hoping that it is that part, although considering that the error code comes and goes, I'm thinking the duct tape is the culprit.

Seeing as I have to get another couple of things from the dealer, I might as well inquire about this part as well.

Thanks, I'll keep everyone posted!

bertiejaffa · Post by **bertiejaffa** » Mon 17 Mar, 2014 11:13

Theres no duct tape on mine so looks like I'll be continuing with the crack case sensor

ualla · Post by **ualla** » Tue 18 Mar, 2014 13:27

I think it was the first time ever I was happy to see duct tape being used

So I got in touch with BMW Park Lane - Parts dept and they said that the rubber boot costs £7 + VAT. I've ordered it and will go pick it up on Saturday morning.

I'll attempt the replacement myself on Saturday as well...

ualla · Post by **ualla** » Mon 02 Jun, 2014 12:36

I finally managed to get that rubber boot changed, but unfortunately I am still having the same issue.

I can confirm that now it is happening much less, but I am still randomly getting a very low idle (under 500rpm), then the ECU revving it up for me and then back down and back up etc. This now happens mainly when the car isn't up to temp yet. It has stalled on me a couple of times as well.

Error messages I get are still the same.

What do you guys reckon I should check next?

bertiejaffa · Post by **bertiejaffa** » Mon 02 Jun, 2014 21:03

Oh no - I did also read another post that blamed poor oil... not sure how this would be the case but an oil change is also very simple and easy (apparently - still not done mine yet but there are plenty of posts in the knowledge base...

Mike F - any thoughts?

BladeRunner919 · Post by **BladeRunner919** » Tue 03 Jun, 2014 07:43

Are you sure there are no other air leaks?

ualla · Post by **ualla** » Tue 03 Jun, 2014 08:54

Unfortunately I haven't managed to carry out a smoke test, so I'm not 100% sure that there aren't any other leaks. I'll try to look at the rubber boots again...

Oil wise, I'm quite confident it should be alright as I got the oil changed when I got the car at the end of Jan.

Thanks guys!

Cooper01 · Post by **Cooper01** » Tue 03 Jun, 2014 13:13

bertiejaffa wrote:Cheers for the comments fella... (hoping to attempt my first ever oil change in a few weeks ).

make sure you change those two small O rings in the oil filter area on the shaft!

bertiejaffa · Post by **bertiejaffa** » Tue 03 Jun, 2014 15:42

Cooper01 wrote:
bertiejaffa wrote:Cheers for the comments fella... (hoping to attempt my first ever oil change in a few weeks ).
make sure you change those two small O rings in the oil filter area on the shaft!

Will do - will be following Mike F's instructions on the knowledge base - whilst he doesnt specifically say change them, they are mentioned enough times and confirms that he changes them to jolt my memory

ualla · Post by **ualla** » Tue 17 Jun, 2014 13:21

So, the plot thickens.

I checked for more cracks/holes in the air flow, but I couldn't find any. That isn't to say there are none, but none that I could find anyway.

Saturday morning I ran a few errands and the car did the same thing. Once the engine reaches the optimal temperature, the idle is unstable ranging from 750 to 580, always just about to turn off. This is more evident in continuous traffic. After 5/10 mins it sorts itself out and seems normal with a stable idle around 750rpm.

Saturday evening I went out and as soon as I turned the car on I noticed that something was wrong. The engine was making a sort of put-put-put noise, almost as if it was running on 5 (or less) cylinders (at least that's what I think that put-put-put sound is). I had power voids before 3000rpm at which point all the power became available. Like turbo lag

This was all in heavy traffic and once I got out of traffic it sorted itself out. Again. On Sunday I checked the diagnostic codes and the list was completely empty. Yesterday I turned the engine on and recorded a video to capture the slightly weird noise. Before you look at this video, I was quite shocked regarding how it sounds in the video. In real life it doesn't sound that bad, honest! here is the vid:
http://vimeo.com/98388637

I'm thinking this could be the Vanos seals?

I took the car out for a test drive again yesterday and same thing. After the engine has warmed up (never happens before), the idle is unstable and I have power voids from time to time. At some point, I also heard a very slight misfire.

I've bought a new MAF (aftermarket) to see if that makes any difference, but I am really starting to think it is the Vanos seals.

Any suggestions? Apologies for the long post...

BladeRunner919 · Post by **BladeRunner919** » Tue 17 Jun, 2014 13:30

I'd be wary of using an aftermarket MAF - you could just be adding to the problems.

ualla · Post by **ualla** » Tue 17 Jun, 2014 13:32

Point taken. I just wanted a quick test so I can see if it makes any difference. I'm guessing not so if my MAF is fine then I'll put my original back in there...

I was a bit wary myself.

BladeRunner919 · Post by **BladeRunner919** » Tue 17 Jun, 2014 13:35

The problem is that a new aftermarket one could be as bad a a faulty one, so potentially you won't learn anything if there's no change. Is there another Z3 owner in the area with the same MAF that you could try out?

ualla · Post by **ualla** » Tue 17 Jun, 2014 13:42

Wow, that bad? That's pants...

Unfortunately I don't really know anybody with a Z3 near me (SW London area)...

BladeRunner919 · Post by **BladeRunner919** » Tue 17 Jun, 2014 13:45

Not always, but not guaranteed to work properly, so if you see no improvement there's no absolute guarantee that your maf was bad.

ualla · Post by **ualla** » Tue 17 Jun, 2014 13:46

Understood, makes sense.

I still have the impression that the symptoms lead to a vanos seals issue...

Thank you!

Del · Post by **Del** » Tue 17 Jun, 2014 22:10

In my experience the things that can "play up" when the engine gets very hot in summer traffic etc. are 1) EGRs and 2) Crankcase breather valves. On the basis that you haven't got the former, I would suspect the latter.

ualla · Post by **ualla** » Sun 06 Jul, 2014 12:35

Hi all,

just a quick update on this. I got my Vanos seals fixed (bought the i6 Automotive rattle kit online) on Friday and my idle seems as smooth as it should be and I don't seem to be getting any dips etc.

It was slowly getting worse and worse, so it is quite a relief that I seem to have found the issue.

I'll update again if there are any updates.

bertiejaffa · Post by **bertiejaffa** » Sun 06 Jul, 2014 20:36

Was it easy to do?

ualla · Post by **ualla** » Sun 06 Jul, 2014 20:47

I admit that I originally wanted to make the fix myself, but after having had a look at the following walkthrough I opted with taking it to a mechanic:

http://blog.bavauto.com/13829/bmw-diy-d ... -cylinder/

Took a couple of hours (and I got the rocker gasket replaced at the same time).

bertiejaffa · Post by **bertiejaffa** » Sun 06 Jul, 2014 20:54

Ok ta... I think I will have to consider this. Will probably try the oil change first, then the crank case breather valve and then finally this. I might even write a book on it

ualla · Post by **ualla** » Sun 06 Jul, 2014 20:55

Haha, I agree. There's so much that could be written