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170 TDi Quattro power loss and economy

Discussion in 'Audi S4/A4/A4 Cab (B7 Chassis)' started by Mini-mad-matt, Oct 5, 2010.

  1. Mini-mad-matt
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    Mini-mad-matt Member

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    [Oct 5, 2010]
    Now then, here goes, could be a long one.
    Picked up my car (see sig.) 10 days ago after having a 1.9TDi 130 for 4 years.
    At first, I was too wrapped up in the creature comforts to properly realise that it doesn't feel nearly as powerful as it should. What I did notice however straightaway was the fact that under hard acceleration, changing gear was not smooth as power dropped too much over the change.
    I did start to realise that it wasn't fast at all, and economy was appaling (32mpg driving really carefully)
    My mate who works for an AUDI main dealer had a go last night, drove it about 30 yards before saying it felt as flat as f**k. He had a new A6 TDi 170 and took me out in it. MAJOR difference. It felt like arocket compared to mine. I thought it may be the MAF sensor. Changed that and just the same. There are no fault codes showing.
    At this point, let me add that when stationary, the engine won't rev above 3000RPM. After a tap of the EGR valve, it suddenly revved all the way round as it should, but once I started to drive it on a test run, it reverted back to being underpowered and not revving over 3000RPM when still.
    So, my question is this. WTF IS WRONG WITH MY BLOODY CAR????:banghead:

    Thanks in advance

    MMM
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  3. slepy
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    slepy Extremely smart and handsome person. VCDS Map User

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    [Oct 5, 2010]
    When you drive it goes over 3krpm?
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  4. Mini-mad-matt
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    Mini-mad-matt Member

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    [Oct 5, 2010]
    Certainly does, just not with a great deal of power. Feels more like 100BHP than 170!
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  5. slepy
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    slepy Extremely smart and handsome person. VCDS Map User

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    [Oct 5, 2010]
    Did you check if there are any oil leaks around turbo? Any boost leaks?
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    [Oct 5, 2010]
    No oil leaks as far as I can tell. As for boost leaks, I don't think it is that. Can hear the turbo spinning up normally, and I can feel the boost. I know I could still be losing some boost, but I just don't think it is that due to this not revving past 3000 rpm unless moving. Like I say, it did rev past that after tapping EGR valve, but then went back. The EGR is prime suspect IMO, but just thought I'd ask as some of you will certainly know more than I do about the workings of it all. My (excellent) mechanic mate who is looking after it suspects it too, and is asking on the LAUNCH forum tonight for any known problems with this model. There was a post on that particular forum from someone who had the exact same problem but from a 140. At the time of looking, there had been no reply to him. I do have a 6 month AA waranty on the car for what it's worth, and it has a FASH, so hopefully if it's something expensive, that will cover it!
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  7. Mini-mad-matt
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    [Oct 6, 2010]
    Quick update. just found out (from a SEAT forum) that the not revving past 3k when stationary is normal. It's VAG's kind of launch rev limiting. It only limits the revs when the clutch is pressed, hence why I thought it didn't do it after tapping the EGR valve. I simply wasn't pressing the clutch at the time.
    Back to the drawing board! No fault codes, running smoothly except under hard acceleration. Turbo spools up fine with a lovely whistle. I can't see any evidence of leaking boost, but that doesn't rule it out. I've had no DPF warning lights (or any for that matter). It's peckin' me head now!

    MMM
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  8. Mini-mad-matt
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    [Oct 6, 2010]
    Another update. Had a bit of a mess earlier and thought I found a slight kink in one of the vacuum pipes. Straightened it out and came in for my tea and to put my lad to bed. Just took it out. It went like the proverbial sh1t off a shovel. Still a bit flat before the turbo, but from what I've read, that's normal for a 170. Anyway, I reset the computer and went on a quick toddle round. Half duel carriageway at a steady 60, and then back on normal roads at about 33. All in all about 11 miles. It averaged 44.5mpg. I can live with that for a 170 quattro. It has previously averaged 32 over the whole combined cycle.
    By the way, before I did that economy test, I did a 0-60 crudely and honestly with my stopwatch. It was 10 secs dead. Would that seem a bit slower than expected, or about right for a non test driver? Going to get it booked in for a custom remap now to try to smooth it out a bit. Power certainly there now!
    Cheers
    MMM
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