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The mkiv Supra Owners Club

BMW 535d - odd smaller turbo problem


johnny g

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Right, got a 54 plate 535d, 80k on it. Full BMWSH, yadda yadda yadda.

 

When starting from cold (i.e. first thing in the morning - or after 8 hours outside work) it performs flawlessly, until I turn the engine off.

 

Now, if I stop for for fuel/shopping/etc and switch it back on, I have no small turbo. There's no strange noise, just doesn't engage. If I get the revs up enough, the large turbo comes online, no problem and it flies, like it should.

 

The only way I get the smaller turbo to work again is to leave it overnight or for a few hours. I left it for 3 hours last night and that wasn't long enough, but this morning, all was well.

 

This has only manifested itself in the last 72 hours, there's no smoke, no warnings on the iDrive.

 

I'm going away to Portugal for the weekend, so I've not booked it in with BMW yet, till I get back, but I was wondering if anyone knows what that is? Or what it only works after some period which is greater than 3 hours...

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Are you sure its not a single variable vane turbo thats stuck open when hot, its a common problem as they get sooted up.

 

EDIT: my mistake, a little googling and it does indeed have a small and larger turbo in sequential operation :search:

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Are you sure its not a single variable vane turbo thats stuck open when hot, its a common problem as they get sooted up.

 

EDIT: my mistake, a little googling and it does indeed have a small and larger turbo in sequential operation :search:

 

lol yep -- i know my cars :)

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Well if it's actually got a small and large turbo, then it's completely different to the Supra seq system!! I'd imagine only a BMW person would have a clue what might be wrong!!

 

Yep. will throw it in when I get back - just seeing if there were any clever people on here ;)

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Could it be a sensor youth? Maybe when its cold the resistance is normal but when its hot the resistance has increased and causes a fault? Dont know the layout so Im clutching at straws... Id probably say electrical cos if it was mechanical wouldnt it be fooked all the time?

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Could it be a sensor youth? Maybe when its cold the resistance is normal but when its hot the resistance has increased and causes a fault? Dont know the layout so Im clutching at straws... Id probably say electrical cos if it was mechanical wouldnt it be fooked all the time?

 

That's what I'm thinking as well, Craig. It could be a VSV-like device which is just not flowing.

 

I'll bung it in and get it looked at next week...

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  • 1 month later...

Just to update, I've had this fixed - a few weeks back actually - it was a small piece of vacuum pipe that had chaffed a little. Replaced, and many torques are restored.

 

If anyone's ever got this problem, it's under the engine cover, left side as you look at it.

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  • 3 years later...

hi there i was reading the problem you have on your 535d, i have exactly the same problem on my 535d, i was just curious to see if this problem has been fixed, i noticed you said theres a pipe or something like that could you please advise thanx

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hi there i was reading the problem you have on your 535d, i have exactly the same problem on my 535d, i was just curious to see if this problem has been fixed, i noticed you said theres a pipe or something like that could you please advise thanx

 

The vac pipes under the engine cover are prone to going on these, as are the plastic T-Pieces that join them together. The vac pipes run along the top of the engine, but you need to take the plastic cover off first.

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Exactly that. Remove the engine cover, on the left as you look from the front. There are some vacuum lines from the switching solenoids. Find the smaller turbo and trace it, there's been a fray/crack in it. Just replace that.

 

Cost me about £3 :D

 

Just had a 2005 535d in with this exact problem believe it or not!! Pipes run above where the DPF / manifold etc is so they get really hot and brittle, found a small black vac hose actually split in 2 on this one!! Interestingly Jonny, did yours flag a DPF fault P14A7 because of it at all? Did the throttle reset on this one too, accelerator pedal to the floor and then switch the ignition on and leave the peadl on the floor for 30-40 seconds, worked a treat! :D

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Just had a 2005 535d in with this exact problem believe it or not!! Pipes run above where the DPF / manifold etc is so they get really hot and brittle, found a small black vac hose actually split in 2 on this one!! Interestingly Jonny, did yours flag a DPF fault P14A7 because of it at all? Did the throttle reset on this one too, accelerator pedal to the floor and then switch the ignition on and leave the peadl on the floor for 30-40 seconds, worked a treat! :D

 

I never got a code, no. That's what caused me the headaches - but yea, as soon as it was fixed, we reset the throttle/'box and it was perfect for another 100,000 miles, till the turbos went at 180k miles. Replaced the turbos, still going strooonnnggg!!!

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