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Bought an Avant. Advice please.

Pornstarr Mar 20, 2008

  1. Pornstarr

    Pornstarr Member

    So, further to my earlier post, I've managed to buy one.

    It's a yellow S4 avant.

    It's all round a very nice car, with a few small problems.

    The rear bumper has had one corner touched in and it doesn't match. So I'm gonna remove it and have the whole thing re-painted.

    The car is down on power, It's a bit lacking in torque. APS have seen the car previously, and from memory say that it's a timing sensor problem on an otherwise very good car.

    I'm going to change the Hall sensor, timing belt + tensioners, and at the same time do a water pump (hopefully metal impellor type).
    Oh, and the rocker cover gaskets. Every S4 I've looked at has had a slow leak from these, so I'm not too concerned about that.

    The question I guess is. What else should I change when I'm in there?
    What else might cause the lack of power? It's had a new maf and one new lambda. Also N75 and diverter valves replaced. So I suspect it's not an air leak.

    I havn't got VAG-com to check it with, but my brother plugged in a 1551 from his audi dealership and it came up with nothing to write home about.

    So......Advicve...always welcome.
  2. Biglockie

    Biglockie Aye you know it makes sense

    DO the work then try it for a week or two, there will be some one on here with VAG-COM near you whomight run the program for you
  3. docurley

    docurley Moderator Staff Member Moderator

    Check all the pipes for any tears or leaks also it may pay to change the DV's and maybe look at the MAF as the MAFis a known problem maker on the S4's.
  4. Blue_Thunder

    Blue_Thunder Well-Known Member

    May as well do the cam belt if you're doing the water pump.

    Don't be so quick to jump to the conclusion that you haven't got a boost leak as the S4 has plenty of problem areas. Get a pressure test done on it to rule that out. If you get Vagcom, you can check the long term fuel trims, readings far from 0 on these can also indicate a boost leak.

    Common places for leaks (aside from the DV's you've mentioned) are F-hose, TBB and the intercooler end caps, although a leak can occur anywhere.

    I actually had an internal boost leak which a couple of specialists had not seen before. Turned out to be worn one-way valves which caused boost to escape out of the breather pipe back into the Y-pipe.

    Your other lambda could be duff as well. Mine has also recently had both lambdas replaced as one giving dodgy readings, however the inaccuracy was not sufficient to trigger an error code (there are quite high tolerances). Same goes for boost leaks. A fault code will sometimes only appear if the leak is significant enough to cause imminent damage.

    Welcome to the wonderful world of car induced poverty!
  5. stapo69

    stapo69 All hail the mighty quattro!

    I agree, get it pressure tested, check for boost leaks, seems the next logical step. Only the other thing i've had problems with are dodgy exhaust gas temp sensors, caused mine to be down on power as a fault here knocked it back to limp mode, but I'd expect it to show a fault code for these. Where abouts are you? Someone on here might have Vagcom local to you. I'm near peterborough, cambridgeshire and I have a copy and a lead.
  6. Pornstarr

    Pornstarr Member

    I'm in Northants. Just outside silverstone.

    Disconnecting the MAF makes no difference in the way the car drives, so I suspec that it's ok. Was only replaced recently though.

    Had a new hall sender recently too. But still throwing an error. So I'm more convinced now than ever that it's a problem with the way the cambelt was done, and perhaps one of the pulleys is a tooth out.

    It wasn't done by an Audi garage, so I suspect they didn't have quite the correct locking tool with which to stop them from drifting.

    Going to my Bro's audi dealership on wednesday for new brake pads and discs. And we're going to run another diagnostic on it.

    Frigging airbag light has come on again......there's a recurring theme of this in the service history. So we may have to delve deeper there.
  7. Check the connction under the front seats. It's a common problem, happened to me. Pain that you need VAGCOM to switch it off again.
  8. Pornstarr

    Pornstarr Member

    plugged it into the 1551 at Audi today.

    The airbag light is the passenger side bag, high resistance. sporadic
    Gonna check the plugs, but mate says it could well be the bag itself.

    The MAF sensor is reading a 'low' fault.

    Air intake sensor is reading abnormal. sporadic.

    And what I presume to be the boost sensor/controller is reading abnormal.
    I can't remember exactly what it was called on the PC, and my bro started wiping stuff too quick for me to make note. But I presumed it to be a boost controlling valve. N75?

    Other than that, the car is clean underneath, and in decent nic. Which is nice. :blackrs4:

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