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VW Sharan - Loss of power


tonyc1968
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Hi Tony,

Welcome to Tyresmoke.

It would help if you mention which engine variant the Sharan has.

There are some quick guides ot help dianose, but basically (if I remember right) if you disconnect the MAF and the car still runs the same the chances are it is the MAF that is at fault.

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Shao,

Thanks for the quick reply - sorry the engine is a 1.9TDI 115 Sport Auto

Yes thats a good idea, I'll give that a go

The other thing that might be worth mentioning is that when the car is in neutral I can rev it up to the red area no problem, its only when it is in drive that the problem occurs.

Thanks

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If you do a quick search in the VW sections you will find a description in detail on what to do to disconnect the MAF and what to expect - basically if it does the same when unplugged it is likely to be the source of your problem.

If that doesnt help, it might be worth getting a diagnostic tool plugged in to see if you have any errors registered.

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  • 2 weeks later...

All poiinted to the MAF but I still have the same problem since I've changed it

The car seems to run fine while drving on a flat road or downhill, revs and speed pick up but when the car is under load going up a hill this is when the loss of power happens and there is no acceleration whats so ever

any ideas much appreciated, in the meantime I'll take a look at getting the diagnostic tool

thanks

Tony

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Is there a sudden loss of power, or is it not there at all? There should be a surge of turbo power when you get to about 1700 - 1800 revs, and then boost all the way to 4k plus, and I bet you don't get this, right? I suspect a stuck VNT (part of the turbo) and you're not getting any boost at high revs. Loads of posts about this under my username, so have a search and see what you think. The VNT can be un-stuck with a bit of hard working back and forth, a squirt of wd40, and a bit of luck.

169144-ok.gif

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Full power is there on engine startup and acceleration is good until I hit 3000RPM then there is the loss of power. The loss of power stays until the engine is switched off. On the restart of the engine power is good again and this is why I think the ecu is putting it into limp mode.

During the power loss I can rev it up past 3000RPM's with the car in neutral but in drive the car wuill not go above 3000RPM's

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The VNT is a vacuum actuated system. Basically there's a valve which controls vacuum to the actuator (not relevant here) and the actuator just pulls and pushed a rod. The other end of this rod is connected to a spindle which goes inside the turbo and moves the vanes for the "variable" bit. These vanes tend to get carboned up and stick, so you need to get a pair of pliers and work the whole thing back and forth to scrape the carbon off the vanes.

This thread explains how the thing works, and the pics show the actuator and where it's located. Link.

If you can't get it freed off, yep, it's a new turbo or a strip down.

However, every time your ECU shuts down the turbo, it'll store a fault code in the memory. If you can get this code read and post it back here it'll help diagnose the fault rather than just taking my guess as gospel. Dealers charge about £75 for reading fault codes, independents should be cheaper, and someone with Vagcom will doubtless be cheaper still. 169144-ok.gif

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Yep, it's pointing to the VNT actuator or a vacuum leak in the vacuum pipe leading to it. Possibly even a sticking N75 valve (which controls the VNT by switching vacuum to it). Check the vacuum pipes for splits, leaks and suchlike, and check that the vnt is moving to its full extent. should be just about 3/4" if I remember correctly. These will cost you nothing except a length of vac hose at most. 169144-ok.gif

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  • 2 weeks later...
  • 2 weeks later...

Well not quite spot on, I was thinking it was a problem with the turbo control system judging by the fault code, but what you say sounds like a boost hose split which would usually throw a code like "17964 - charge pressure control: negative deviation".

Anyway, glad it's all sorted.

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but you did mention "Check the vacuum pipes for splits, leaks" and it was the boost pressure hose that they replaced

I took it to my local garage (seat dealer)in the end as I've been quite busy, they charged £45 and that included the car being washed so much cheaper than the main vw dealers who would have charged around £90 for just sticking on the diag machine

anyway a big thanks for your help

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  • 4 years later...

Hi there

I have the exact problem decriber above with my sharan.

Its manual not auto tho, does this have any bearing on the fault?

Thanks in anticipation of your reply!

Skyeley

p.s. sorry but im a complete car noob so any technical jargon will ave to be put simpler cheers

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  • 2 months later...

I'm glad to hear that I'm not the only one with this problem. My sharan has the exact same problem as described in this thread. The power disappears randomly. If I shut off the engine 8 times out of 10 the power is back when I start it up again. Sometimes it lasts and sometimes it disappears again. I changed the MAF which didn't help. I'm getting revved up the give the turbo a work over ... hope it solves the problem ?

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