[DaanBMW]

Long term update: did reset adaptations (throttle, even VVT) using BT tool. After an ok 1st drive (key had been left in), the 2nd drive (key was out) the car drove like a tractor and threw a half-full yellow engine symbol and 'Service engine soon' came on. Thought I f... it up, then read about some non-tool resets and finally got the car back to normal.

While that was a huge relief given the absolutely miserably way it drove, the issue is the same - on a hotter Thu this week it died again when pulling out of gear w/ a/c on.

So, my ideas now:

1. Throttle - Three_thirty_I said these cars don't have a idle control valve anymore. I did find a Throttle Housing Assy on realoem: http://www.realoem.com/bmw/enUS/show...30#13547556118 . So what about a stuck throttle valve - assuming that's what's inside this assembly ? But why is it acting up on a/c only ?
   
2. VVT motor - according to this http://www.e90post.com/forums/showpo...2&postcount=16 this might be the culprit. Has anyone done it and why and what were the results ? And why would it only do it w/ a/c/ on ?
   
3. VANOS solenoids - given I'm on my 3rd at least on intake (even if all used) I don't think this is the cause.
   
4. Eccentric shaft sensor - mine seems dry so I don't think this can be it.

Feel free to throw out any ideas you might have...

[ncd328ie90]

eccentric Shaft Sensor?

[DaanBMW]

Originally Posted by ncd328ie90

eccentric Shaft Sensor?

I had looked at it earlier, seemed dry... I have on the list of possibilities at #4

[Camman]

I think he was asking what the eccentric shaft sensor was. I'm curious to know as well.

I have an update to this. Whenever my car dies and restarts, it acts much differently. Particularly the way the throttle responds is very different. If I do a quick push on the gas peddle, the revs are slow to respond. So I wonder if this has something to do with the throttle.

Also I want to add that this same of behavior will happen after a long drive on the highway with the A/C on. Once I hit the city or traffic and I have to come to a stop. I will notice that the car is acting strange again. So Ill turn it off, take the key out, put it back in, start it and we're back to normal.

So something tells me this has something to do with some kind of throttle control.

[simster007]

I had this problem in the summer with A/C on. Running in sixth and stopping for traffic, clutch in and dropped like a rock down to 0. I gave it up to partially the oil health in the vanos solenoids, the fuel pump not kicking in fast enough because you're coasting or low throttle. For me at least, only happened after 2 hours of driving on highway and went away after I cleaned my vanos solenoids, and changed my oil. Granted I bet I can replicate this if I tried, but hasn't happened to me since the beginning of summer.

I believe these engines really are finicky with the oil. This is in part due to more of the vanos controlling the valve timings over the throttle body controlling the air coming in.

To solve this? I thought maybe a better ECU tune, or fuel pump. But IDK... start off with fresh oil, vanos solenoids and filters cleaned out.

[DaanBMW]

Sorry been out for a while...

Re simsister's fuel pump mention above. That is actually smtg I read about as a potential issue, however never reading in the context of a e9x I thought maybe it does not apply here. But maybe it does ?...

thread I had read: http://www.bimmerforums.com/forum/sh...-Surge-LOW-RPM

[DaanBMW]

long term update: I changed solenoids, MAF, VVT motor so far. Nothing helped . I guess I'll try the check valves next ? or randomly replacing coils ? never had any codes.

[avocet]

This makes me think of the throttle position sensor... but I don't think the n52 has one. I think there is a pedal position sensor...

[DaanBMW]

Originally Posted by avocet

This makes me think of the throttle position sensor... but I don't think the n52 has one. I think there is a pedal position sensor...

AFAIK the VVT is handling it all, the throttle stays open during engine operation. I also checked the throttle body is seemed fairly clean.

The idle is pretty nice & stable otherwise. I have started to notice that the rpms dip a bit even w/o the a/c on (when taking it out of gear), but obviously the added load of the a/c makes the whole rpm dip more pronounced, at the limit having the engine die off.

So the issue seems to be the that engine rpms dip shortly below the normal idle (600 rpm) and then depending on load and chance, it recovers back to idle speed or dies off.

[Camman]

I fixed my issue. Turned out to just be a bad Camshaft Positioning Sensor (exhaust side). Once I replaced that, my car stopped acting up. If you haven't tried the camshaft positioning sensors, give them a try. They're not terribly expensive and easy to replace.

[DaanBMW]

Originally Posted by Camman

I fixed my issue. Turned out to just be a bad Camshaft Positioning Sensor (exhaust side). Once I replaced that, my car stopped acting up. If you haven't tried the camshaft positioning sensors, give them a try. They're not terribly expensive and easy to replace.

Wow, that is definitely something I've not read before. What exact sensor is this, I can't find any such sensor using realoem ? Can you, or do you have a part number ?

[DaanBMW]

After some research - is it the Pulse generator (what a suggestive name), seen here (for my car): http://www.realoem.com/bmw/enUS/show...36#13627525014

[Rustymage]

My car is booked in on the 9th Aug for a check over at an indy specialist. I will wait before changing any parts. I will however present the VVT (25742810-PUMA) just in case that helps.

The guy sounded like he knew what he wanted to check as per this post (http://www.e90post.com/forums/showpo...&postcount=261)

Maybe he will attempt the PUMA once he has looked at coils, plugs, injectors etc!

I have included a plug to ensure that anyone searching for the issue will find this post and others. Hopefully it'll help.

I will update once the car has been in for a check up on the hesitation issue.

Anthony

[Camman]

Originally Posted by DaanBMW

After some research - is it the Pulse generator (what a suggestive name), seen here (for my car): http://www.realoem.com/bmw/enUS/show...36#13627525014

Interesting because I never heard that term before. From the research I did, everyone was referring it as the camshaft positioning sensor. I found the parts through this DIY tutorial

http://www.pelicanparts.com/BMW/tech..._Replacing.htm

[DaanBMW]

Originally Posted by Rustymage

I will wait before changing any parts. I will however present the VVT (25742810-PUMA) just in case that helps.
[snip]
Maybe he will attempt the PUMA once he has looked at coils, plugs, injectors etc!

This PUMA is quite an obscure reference, could find v. little about it. Can you elaborate ?

Originally Posted by Camman

Interesting because I never heard that term before. From the research I did, everyone was referring it as the camshaft positioning sensor.

Yeah no kidding, that's I couldn't find it in realoem. How did you know it was the exhaust and not the intake CPS ?

[Rustymage]

Originally Posted by DaanBMW

This PUMA is quite an obscure reference, could find v. little about it. Can you elaborate ?

I couldn't find any official article on it either so it's origins remain a mystery. But people claim to have fixed the hesitation based off that PUMA.

I will speak with the specialist and see whether they can confirm what a PUMA is and whether this one is even real...

I'll update once the car is in (9th Aug '16)

[DaanBMW]

Originally Posted by Rustymage

I couldn't find any official article on it either so it's origins remain a mystery. But people claim to have fixed the hesitation based off that PUMA.

I will speak with the specialist and see whether they can confirm what a PUMA is and whether this one is even real...

I have seen a lot of references to it too, mainly on UK sites. If you can get as much info as possible on it I'd appreciate it, it sounded to me like some sort of VVT fine tuning procedure...

...and then I read these so I'm really confused now:

http://www.bimmerfest.com/forums/sho...d.php?t=349739
http://www.m5board.com/vbulletin/e60...ml#post1112810

[DaanBMW]

replaced the exhaust side CPS (camshaft positioning sensor) -> car definitely drives differently - it has more snap, it accelerates better. but I can still see the rpm drop if I take it out of gear after coasting. not so bad as before... ? maybe, not really sure yet.

@Camman - how did you determine it was the exhaust and the intake was fine ?

...based the result so far I ordered another CPS and I'll swap the intake side too.

[sub150]

Sorry for bringing up an ancient thread...

Does anyone have any other potential fixes for this? I am in Phoenix so it's hot quite a bit here and I have the AC running . I'm having the same issues as others. I typically get around it by just staying in gear, braking, and pushing in the clutch once RPM's get to about 2k. The drop seems to not be big enough to stall the car.

I'm finally getting some time to work out the small issues on the car. It's been great overall but this is just annoying to work around!

[DaanBMW]

I for one have not found one