[dai_call_me_dave]

Hi, I'm New to this Forum.

I bought a 335d about 6 wks ago, which up until Saturday was working fine. Now the engine has developed a strange problem.

When accelerating hard from stand still the car pulls hard in 1st 2nd 3rd gear but by the time the car is into 4th gear at about 80mph the power drops, it feels like there's no boost.

It's like the engine will only maintain full boost for about 8 - 9 seconds.

The boost will come back if I’m not driving to aggressively.

There's no smoke or strange sounds, so I doubt’s there's anything wrong with the turbo's.

I took the liberty of attaching a web camera under the bonnet so I could see the cross connection actuator (the valve on the bit of pipe between the big and small turbos) under different engine loads.

It appears that the actuator opens up fully at the same time as the boost drops off, this makes me think the ECU has decided to limit the boost? or could be a problem with the actuator control valve?

I would love to know how this is set up, very complicated!

I’ll have a look later to see if the boost pipe has come loose.

No warning lights up.

I intend to get the DIS diagnostic package & cable so that I can monitor the boost. Can DIS datalog? It would be nice to see pedal position, engine speed, boost pressure etc while driving.

Any Ideas?

p.s. It's out of warranty.

[rsmallwo]

I've heard of boost pipe problems on 335d, i might just be imagining this.

[richy_335d]

Check the boost pipe. The red one down between engine and radiator. Left hand side as you face the engine. If it's got oil on it the seals have gone. Common fault on these

[elucid]

I had a similar problem as the OP describes a few months back. Acceleration up to 30 mph was ok-ish, but after that milk floatesque. Coming out of a 50 mph restriction on the motorway and building up to speed to 70mph took around 30 seconds.

No warning lights and the car drove fine (albeit with glacial acceleration rates) for a week until I could get a slot at the dealer.

I had both turbo actuator valves replaced under warranty which fixed the problem.

[dai_call_me_dave]

Now the power has completely gone! It feels like there's no boost, like driving a non-turbo diesel!!.

Richy - the red pipe has got oil on it, what seals? Oil seals within the turbo itself? sounds expensive!!

I can't hear any air leaking, you would expect hell noise if there was a leaky boost pipe.

P.s. - Iv been studying the BMW TIS manual to get an idea of the turbo arrangement, including turbo sequence etc, Very good article, I will post it as a pdf if anyones interested.

[elucid]

dai - the red boost hose issue is well documented here:
http://www.e90post.com/forums/showthread.php?t=281232

I had my red boost hose changed. Tbh I wasn't even aware of the issue and the car drove pretty much the same before and after these seals were changed. I guess it depends how poor the seal has become.

To me your issue sounds more like turbo actuator valves which failed on mine and made the car feel like a 0.5d rather than a 335d. Here's thread for a similar issue:
http://www.e90post.com/forums/showthread.php?t=333172

[dai_call_me_dave]

Thanks for the advice Elucid.

The big loss of power I have now experienced feels like the big turbo is shut off, theres a bit of boost below 2000 rpm then nothing.

I got the web cam hooked up again earlier (bargain bit of fault finding equipment - 11 quid from tesco!) and took it for a spin.

The big actuator doesn't even move any more.

I'm thinking it is definatley actuator related, either:

1. - A vaccum pipe has come loose
2. - Actuator/valve has seized
3. - The vaccum control unit
4. - The vaccum pump

I'm leaning towards vaccum control unit as it seems to be a common problem.

Iv got a copy of DIS v55 (diagnostic SW) and a cable is coming in the next couple of days so hopefuly I can test the actuator through my laptop.

I will update as soon as I know more.

[milesr3]

The front actuator valve seized on my 535d which meant the small turbo was effectively bypassed and providing no boost at all below ~2,500rpm.

It struggled to maintain 70mph on a slight incline in 6th, but drop it a couple of gears and it went ballistic (as usual).

BMW ran a diagnostic test on it to find the fault and fitted a new valve which sorted it along with doing the vacuum hoses and accumulator. It's a not uncommon problem on the x35d engine.

[dai_call_me_dave]

Manged to fix it on the week end. It was the pressure convertor (£68 from BMW). This controls the vaccum pressure and hence moves the turbine actuator, which in turn opens and closed the turbine control valve (effectivley the large turbo).

Although I may have saved myself a few quid (I read thas BMW charged somone £700), it was not an easy job, it took about 6 hours simply due to the difficulty in accesing the part.

[rsmallwo]

Interesting....

I've just had the 2nd turbo in my car feel like its gone on strike. Get boost upto around 2k rpm and then nothing in any gear. I restarted the car and then got alittle boost from the 2nd turbo but not a great deal and the delivery was abit rough, not the smoothness I'd expect.

Thing is my turbo boost pipe was replaced under warranty last week. I was hoping that had come off/loose but when looking at it I can't see if it has or not (limited visability of it).

I'm deliberating on wether going back to the dealer who did the boost pipe or going to my Indy to fix the pressure convertor as 'dai call me dave' describes, as labour cost from main dealers is ridiculous.

My car: 335d, 88k miles, Sept/2006 build. remapped to 340bhp

[briers]

Originally Posted by rsmallwo

Interesting....

I've just had the 2nd turbo in my car feel like its gone on strike. Get boost upto around 2k rpm and then nothing in any gear. I restarted the car and then got alittle boost from the 2nd turbo but not a great deal and the delivery was abit rough, not the smoothness I'd expect.

Thing is my turbo boost pipe was replaced under warranty last week. I was hoping that had come off/loose but when looking at it I can't see if it has or not (limited visability of it).

I'm deliberating on wether going back to the dealer who did the boost pipe or going to my Indy to fix the pressure convertor as 'dai call me dave' describes, as labour cost from main dealers is ridiculous.

My car: 335d, 88k miles, Sept/2006 build. remapped to 340bhp

Definitely sounds like the pressure convertor

Exactly the same happened to me - mine was replaced under warranty but bill i think with pipe replacements and pressure convertor on both turbos would have been around £600.

[rsmallwo]

Thanks for the reply briers,

Do you think the dealer replacing my red turbo boost presure pipe is unrelated then? could the dealer have caused this issue? The car has run for about 250miles since they worked on it.

Will there be fault codes on the computer for this kind of issue? i.e. my Indy will get a picture of whats going down early on?

[rsmallwo]

Been out again with a mate and I can't see the red boost pipe moving at all when given some beans nor can I hear or see air escaping the pipe. In first the car gets upto 2k rpm as normal and then keeps going with limited shove but is laggy and rough. Suspect I need to get wallet out and start spending on the pressure convertor......
.

[acerboo]

Originally Posted by dai_call_me_dave

Manged to fix it on the week end. It was the pressure convertor (£68 from BMW). This controls the vaccum pressure and hence moves the turbine actuator, which in turn opens and closed the turbine control valve (effectivley the large turbo).

Although I may have saved myself a few quid (I read thas BMW charged somone £700), it was not an easy job, it took about 6 hours simply due to the difficulty in accesing the part.

can you provide more info on what you did and where its located for future reference to those with these engines thanks.

[335DEE]

Originally Posted by acerboo

can you provide more info on what you did and where its located for future reference to those with these engines thanks.

+1

[rsmallwo]

Originally Posted by rsmallwo

Interesting....

I've just had the 2nd turbo in my car feel like its gone on strike. Get boost upto around 2k rpm and then nothing in any gear. I restarted the car and then got alittle boost from the 2nd turbo but not a great deal and the delivery was abit rough, not the smoothness I'd expect.

Thing is my turbo boost pipe was replaced under warranty last week. I was hoping that had come off/loose but when looking at it I can't see if it has or not (limited visability of it).

I'm deliberating on wether going back to the dealer who did the boost pipe or going to my Indy to fix the pressure convertor as 'dai call me dave' describes, as labour cost from main dealers is ridiculous.

My car: 335d, 88k miles, Sept/2006 build. remapped to 340bhp

Had my issue fixed, was the pressure controller/convertor as Briers suggested. My Indy replaced that and a whole host of vacuum pipes as they where looking corroded for £350 all in. Billed me for 5hrs labour but took him more like 8-9hrs. Think the Vac hoses didn't cost more labour to replace, just £20 in parts. My local indy is Autologic of Hessle.

My car flys again

[Brian mc21]

Happy days.

[rsmallwo]

Car feels real quick now. Don't know if having the car going "slow for a week" has changed my perspective, like when you drive some hire car then get back in your own beast and it feels quicker than before. Now its just so raring to go its like an angry rhino!!

[335DEE]

Originally Posted by rsmallwo

Had my issue fixed, was the pressure controller/convertor as Briers suggested. My Indy replaced that and a whole host of vacuum pipes as they where looking corroded for £350 all in. Billed me for 5hrs labour but took him more like 8-9hrs. Think the Vac hoses didn't cost more labour to replace, just £20 in parts. My local indy is Autologic of Hessle.

My car flys again

Can you tell me where the pressure converter is ?

I've checked on realoem but it doesn't give much away as far as location goes

for info the part number i have for the pressure converter is 11747796634 and have been assured by the dealer that it is correct and does exist on the car !

[mistryn]

I would be intrested to know the above as well and whether if its home DIY possible to replace it or a garage jobby?

[rsmallwo]

Originally Posted by dai_call_me_dave

Manged to fix it on the week end. It was the pressure convertor (£68 from BMW). This controls the vaccum pressure and hence moves the turbine actuator, which in turn opens and closed the turbine control valve (effectivley the large turbo).

Although I may have saved myself a few quid (I read thas BMW charged somone £700), it was not an easy job, it took about 6 hours simply due to the difficulty in accesing the part.

not for the faint hearted. my indy had to disconnect alot if vac pipes to get to it

[335DEE]

Just had my vac pipes changed and car is a little more spritely . pressure controllers next

I've just forked out on 2 pressure controllers that are on the left hand side rear of the engine. Are these the ones that people refer too when suggesting that there is loss of power ?
Or is it a single unit that resides underneath the inlet manifold ( manifold removal required to get ot it!) ?? RealOEM doesnt really give a functional description so I'm guessing all the way on this.

The 2 pressure controllers i have purchased requires new bracketing too as the design of the controller is different so you can't just change 1 , you have to do both.