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Loss of power - slipping clutch or boost leak?

Discussion in 'A3/S3 Forum (8L Chassis)' started by imported_monkeytrousers, Aug 28, 2005.

  1. Ryanc

    Ryanc Active Member

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    what sort of maf readings are you getting in g/s?
     
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  3. AL_B

    AL_B Active Member

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    Good values actually Ryan.

    From 184-191 g/s. Average I'd say 185 regularly.

    AL
     
  4. Drill

    Drill Member

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    Don't know if it'll help Al, but I've actually killed 2 spark plugs /ubbthreads/images/graemlins/frown.gif First time was a Beru Ultra X that I got while waiting for Iridiums, second time was std Audi plugs (Were the replacements for the Beru's). Not sure how long it took the Beru to die, but the Audi plug lasted about 3 months. (Don't forget, I do over 1200 miles a week) I've now had the Denso's in for about 4-5 months and it still seems OK. Not sure what the problem was because it happened on a different cylinder each time. I think it could have something to do with the fact that I spend alot of time at or around 6k RPM /ubbthreads/images/graemlins/angel.gif

    Each time it happened I got a CEL.

    As far as hesitiation goes... I'm looking at a new clutch soon anyway (147k + miles) so I'll be able to let you know if that's what's causing the hesitation sometime in the next month /ubbthreads/images/graemlins/crazy.gif

    /ubbthreads/images/graemlins/beerchug.gif
     
  5. benk

    benk Member

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    Years back I was getting a flat exhaust POP (sounded like I had run over a thin plank of wood) and the local Audi/VW specialist said he thought that the Power Output Stage (Ignition Amplifier) might be the problem. I don't know if I have already suggested this to you in relation to your power loss...

    Anyway, you can read more here:
    http://www.audi-sport.net/ubbthreads/sho...true#Post191600
     
  6. AL_B

    AL_B Active Member

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    Drill,

    If I get chance I am going to inspect the plugs again this weekend. Take some pics of the colour etc.

    Car seems to be running well at the moment though, no hesitation yet this week.

    I'll look forward to seeing if your new clutch fixes your hesitation.

    Bk,

    It's a good suggestion. According to the manual the ignition coil and output stage are combined into a common component. Which I take to mean the whole coil-pack. I'll have a read of the manual and see what I have to do.

    Cheers

    AL
     
  7. benk

    benk Member

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    Ah yes, I think the newer cars did away with the ignition unit and made more complex coilpacks, and yes, that meant that coilpack problems increased instead of the old ignition unit being the problem.
    Sorry, forgot about that as my A3 was a 1999 model.

    That would seem to send you back to a timing/sparking problem? Assuming the ECU timing is all fine (signals to coils) then spark plugs would definitely seem the next place to look unless you had pressure problems somewhere.
     
  8. Ryanc

    Ryanc Active Member

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    Heard that the early s3 coilpacks were the better ones.
     
  9. Drill

    Drill Member

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    Al,
    Took it in on Friday to have the Service dude take a spin. He figures the clutch is grabbing fine, but there's prolly an issue with the throw-out bearing (Can feel a "wobble" when engaging) so they've ordered the new clutch and we'll be going in Monday morning for the swap. If I remember, I'm gonna ask them to show me the old parts before they toss'em. I'd like to see what a "Good" clutch with over 147k miles looks like /ubbthreads/images/graemlins/grin.gif

    /ubbthreads/images/graemlins/beerchug.gif
     
  10. AL_B

    AL_B Active Member

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    Hi Drill,

    How's the new clutch? I assume you'll be running-it-in a little, before giving it some abuse?

    As for my car, 1 week on since spark plug re-torquing and all seems well. No heistation yet. Power seems good. But do have some surging on part throttle.

    AL
     
  11. AL,

    In my other thread you asked how my clutch was going ....

    Well, it's two weeks since it was changed and yes, things are absolutely fine. The over revving has gone and there's no hint of it coming back. So it looks like it WAS a slipping clutch after all.

    Thing is, the uprated clutch's "bite point" is very tight, so it's been like learning to drive again - easier to stall on take off - it just needs a few more revs really. Gear changes are generally much quicker now. Got used to it now so I don't notice it, but I'm a bit worried about when my girlfriend has her first drive in it since the new clutch /ubbthreads/images/graemlins/shocked2.gif Kangaroo jumps me thinks /ubbthreads/images/graemlins/shocked2.gif
     
  12. AL_B

    AL_B Active Member

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    Cheers mate. I'm sure you'll perfect the launching soon. /ubbthreads/images/graemlins/smile.gif

    Which clutch did you go for in the end? The JBS one?

    AL
     
  13. No, it was an MTM uprated clutch, don't know any more detail than that.
     
  14. Drill

    Drill Member

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    Well, I got a new std clutch fitted yesterday. Not sure how long I need to bed it in, but so far i can say that I'm running a bit smoother. I've only driven it TO work this morning so will have an update in the next few days /ubbthreads/images/graemlins/beerchug.gif
     
  15. Drill

    Drill Member

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    Well, felt a little hesitation on the way home /ubbthreads/images/graemlins/frown.gif Think I'll swap out the DV and N75 next /ubbthreads/images/graemlins/crazy.gif

    /ubbthreads/images/graemlins/beerchug.gif
     
  16. AL_B

    AL_B Active Member

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    Oh dear. Thats bad news mate.

    Let me know how you get on.

    AL
     
  17. god_thats_quick

    god_thats_quick Numptie of the highest order

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    Drill... just a thought but have you tried the coilpacks? one of mine went last weekend and I had noticed before it went completly (very rarely) some hesitation since the new coilpack not happened once and I'm actually thinking I might replace the other three to see if it makes the engine any smoother.
     
  18. Drill

    Drill Member

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    I had the coilpacks all changed to "new" ones about a year and a half ago /ubbthreads/images/graemlins/confused.gif

    Unfortunately, it's the LEAST of my problems today /ubbthreads/images/graemlins/frown.gif

    On the way home last night 5th gear stopped working. All I got was a LOUD grating noise. Took it in this morning and they think I need a new transmission /ubbthreads/images/graemlins/frown.gif

    Anyway, I'm doing a search now to see who it was that replaced their 5 speed with a 6 speed tranny. I'll check back in later.

    /ubbthreads/images/graemlins/beerchug.gif
     
  19. AL_B

    AL_B Active Member

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    Just another update from me. As I think some people may be under the impression that the hesitation with my car has been fixed. It isn't 100% ok yet, unfortunately.

    A form of hesitation is still around, and occasionally the engine sounds a bit rough, possibly a slight misfire. But I can't be sure.

    The hesitation rarely happens now when the car is just going in a straight line, like on the motorway. But once or twice it has happened whilst cornering. This was not aggressive cornering, just a long sweeper. I was in 2nd gear, part to half throttle, and not booting it, and the car hesitated. But the corner was a little bouncy. So I am still wondering if there is a loose connection somewhere.

    Not sure what is causing the roughness one day...and smoothness the next. Car was fine this morning, but was rough yesterday and slightly hesitant.

    I think I'm up to the point of trying the new MAF sensor now. I will be surprised if it is that, because the MAF is recording good values.

    I will battle on! /ubbthreads/images/graemlins/smile.gif

    AL
     
  20. AL_B

    AL_B Active Member

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    Well fellas, an update.

    You may remember, but a while ago I bought a new MAF for my S3, from GSF. But I decided not to fit it, as I don't think the existing MAF is the cause of this Hesitation, loss-of-power problem. The existing MAF meets the flow spec at idle, and in a 3rd gear pull to the red line, flows about 185-190g/s.

    Anyway, over the weekend I decided to fit the new MAF, just to rule out that the old one is the cause of the problem.

    Result. Today is day-2 of running with the brand new MAF, and the hesitation is most definitely still there.

    Hesitation occurred twice this morning, once in 4th gear and 5000rpm, part-throttle load. Second instance, was in 6th gear, 4000rpm, again part-throttle.

    What's next I do not know.

    AL
     
  21. benk

    benk Member

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    Just in case it makes any difference at all, do you have the aircon on auto? I just wonder if it's worth driving the car for a few days with the aircon compressor off to see if there's any chance it might be kicking in at weird times and sucking some of your power. Yes, a shot in the dark, but hell, you've tried everything else other than checking for "bananas in the tailpipe" (name the film for that quote anyone?).

    I haven't read everything you have tried, but did you look in the direction of the fuel pump/filter, etc. I was talking to someone the other day who had a car that kept dumping **** from the tank into the fuel filter, until it got to the point where the filter jammed up so much that it starved the car and everything stalled. Bad maintenance, but still a possibility?
     
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  23. AL_B

    AL_B Active Member

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    Thanks bk. I always drive the car with the air-con compressor off. On the facelift cars this the Econ mode. But like you say, worth mentioning, because the air-con is run from another pulley I think (??), so some extra load. But I can rule that out, because the compressor is never on.

    Fuel...this is one area I have not investigated as yet. Mainly because its hard to investigate. Testing fuel pressure, I know requires special tools. Was looking at fuel pressure testing equipement on JustOffBase tools last night - expensive kit.

    So I think fuel testing would have to be performed at the dealer. But if anyone has any tips, I'd appreciate it.

    Alan
     
  24. benk

    benk Member

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    Fuel-wise, I was thinking that maybe slapping a new filter on might be worth trying.
     
  25. benk

    benk Member

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  26. AL_B

    AL_B Active Member

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    I'll have to look in to it. Possibly a new fuel pressure regulator for good measure too.

    Not sure how much those things cost though.

    AL
     
  27. benk

    benk Member

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    Knock sensors could be an easy one to check, and the info on that site definitely mentions hesitation on acceleration as being a key symptom of a loose knock sensor, which makes sense.

    Have just googled on "audi knock sensor hesitation acceleration" and there are many people who replaced knock sensors then sang about their hesitation having been solved.
     
  28. AL_B

    AL_B Active Member

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    bk, nice one! I will have a read.

    AL
     
  29. AL_B

    AL_B Active Member

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    Did some logging this morning on the way to work, 45-50 minute journey.

    I logged block 20, "ignition knock control whilst driving".

    Basically, according to the manual, the numbers display in display zones 1,2,3,4 represent the actual ignition timing retardation due to knock control of the individual cylinders. The ignition angle retardation is carried out late in degreesKW (crankshaft degree).

    Values should be between 0...11.25.

    My car was mainly 0 on all cylinders. Although cylinder 4 was showing more knock control than any other. Cylinder 4 was mainly 0, but there was the occasional small grouping of 3's or 4.5's. So still in specification.

    So it doesn't look like its knock control. Although this morning the hesitation did not occurr at all. I need to keep logging until the hesitation whilst I'm watching for it with VAG-COM.

    Any other ideas?

    AL
     
  30. Ryanc

    Ryanc Active Member

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    To be honest 0's are pretty standard for a standard car.I now see 6's tops and this is the most you safely want to see.I have seen high 7's with a dodgy tank of optimax but the car has very aggresive timing.
     
  31. AL_B

    AL_B Active Member

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    Thanks Ryan.

    It's doing my head in now this. I'm finding I am continually thinking about the problem, and what the cause could be. It's almost distracting my driving and certainly ruining ownership.

    I had a good read of this whole thread yesterday...

    MikMoila - are you still around? You seemed pretty confident that it could be the dual mass flywheel. Why are you confident about that? PM me if you do not want to share your information on the board.

    Monkeytrousers - you had a new clutch fitted. Did you have a new flywheel too? How's it going? I know you said the bite point was a little snappy, but what about the hesitation? Gone or still there?


    One thing I have been meaning to mention, during say a 3rd gear power run to the red line, boost and this acceleration does not feel linear. It seems to come in waves. I'm not talking a massive amount here, but it feels as though the boost being produced is not smooth and progressive.

    I'm sure someone else has experienced this, but can't remember who it was.

    Any ideas?

    AL
     
  32. jojo

    jojo Looking for Boost!
    Staff Member Moderator quattro Audi S3

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    Al, I reckon a remap would sort your problems /ubbthreads/images/graemlins/tongue.gif
    I remember a couple of years ago, I had an intermittent MAF fault, it would make the power delivery come in 2 stages on a full throttle run. It would boost as the turbo spins up, hesitate for a micro second at around 2.5-3k revs, then full boost to the red line, does that sound familiar? A totally knackered MAF would splutter throughout the rev range, I've had that experience too. /ubbthreads/images/graemlins/smirk.gif
     
  33. HTC

    HTC Active Member

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    Sounds like you've got "surging" as well.

    A couple of things. Have you checked the vacuum connection on the wastgate actuator is okay?

    Also the N249 can open the DV at undesirable moments. Have you tried bypassing it and connecting the DV straight to the inlet maniold to rule that one out?
     
  34. AL_B

    AL_B Active Member

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    JoJo,

    You are not the only one to suggest a remap. Rich, DavidR and Glen (EssThree) have all said it might be worth doing.

    But 600 quid is a lot to spend on something that might not solve the problem.

    Don't know whether to just get shut of the car. Trade in, get an R32 or something.

    AL
     
  35. HTC

    HTC Active Member

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    Jabba will do a custom remap for £475 inc vat.

    Or a generic one for £375 inc vat.
     
  36. Ryanc

    Ryanc Active Member

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    take it too jabba mate,tell mike that ryan sent you he will sort the car.Remap will transform the car too.
     
  37. [ QUOTE ]
    Monkeytrousers - you had a new clutch fitted. Did you have a new flywheel too? How's it going? I know you said the bite point was a little snappy, but what about the hesitation? Gone or still there?

    [/ QUOTE ]

    My new clutch sorted my problem out. The hesitation was a slipping clutch. It was difficult to be sure because the problem was intermittent. I had to be brave and get the new clutch and fortunately it was definitely that. So problem solved in my case. It's 7 weeks since I had it done and the problem has not returned.

    I didn't have a new flywheel.

    I've got used to the harsh clutch, it's bedding in nicely, although still manage some "less than smooth" gear changes!

    I've not got the technical knowledge to suggest what your problem might be, but it really doesn't sound like a clutch problem.
     
  38. AL_B

    AL_B Active Member

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    Thanks for the update mate. I'm glad things are sorted for you, at least someone has had some success!! :)

    Cheers

    AL
     
  39. AL_B

    AL_B Active Member

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    Well, for the first time ever the car hesitated today, whilst I had VAG-COM attached.

    Obviously, because you can only log 3 data blocks at one time with VAG-COM, its hit and miss if you are actually logging the right sort of data or not.

    I decided to log blocks 002 (general load, maf etc.), 031 Lambda, and 115 (requested vs actual boost).

    Have a look at this and see what you think...

    Log jpg

    The marker points are the points where I hit the Shift key a couple of times AFTER the hesitation had occurred. Taking my eyes briefly off the road, spotting the shift key, and pressing it, probably took 1-2seconds maybe. During that time my foot was off the accelerator, hence load drops down to 12%.

    I've highlighted 5 seconds prior to the markers in orange, and I have highlighted what I think is strange lines 1623-1625.

    Cheers

    AL
     
  40. AL_B

    AL_B Active Member

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    Some more information about the drive..

    ...it was on the motorway, 5th or 6th gear, can't remember. 5th I think. Traffic was in front of me, so I was on part throttle. When traffic cleared/started to acclerate, I pressed the throttle lightly, not foot-to-the-floor. It was just enough to feel the turbo start to spool and the car "load-up", come on boost...its at that point, the car hesitated.

    What looks strange to me is for an increase of 40rpm, load jumps from 59% to 153%, Air Mass jumps from 47% to 141%. How can that be? For a slight movement in throttle position.

    AL
     
  41. Drill

    Drill Member

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    Not a nice thought, but do you think the E-gas pedal could be "off" somehow?

    As for Fuel Pressure... don't know if it'll help narrow anything down, but I run a 4 bar FPR on the TQ and still have the problem /ubbthreads/images/graemlins/frown.gif

    Also, new Clutch, new transmission and new DV (all in the last 90 days) and the hesitation remains /ubbthreads/images/graemlins/crazy.gif

    /ubbthreads/images/graemlins/beerchug.gif
     
  42. Drill

    Drill Member

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    Oh yeah, I forgot to mention the new Lambda sensors, Cat and throttle body in the last 6 months as well. /ubbthreads/images/graemlins/crazy.gif
     

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