on my Jan '05 2 litre diesel dsg (37 K) occasionally get no power initially when ascending in reverse my rather steep driveway. Returned to car last night after a week away (damp Stansted long stay) and it happened again, for first time in a forward gear - in first on take off. Feels like engine has died, but still running and power soon comes back. Car goes wonderfully otherwise. It's still under Audi warranty, but before I take the official route, any BR thoughts, pse?
many thanks
EH
PS not sure if this should be under Tech Matters or here {Kicked across - DD}
Edited by Dynamic Dave on 07/12/2007 at 18:41
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EH
Does this feel like the pedal has become disconnected?
Brake lights working OK?
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effectively, Yes, Screwloose - in fact, on small hill start this morn I had no power at all and began to go backwards temporarily. Re brake lights no-one to help look at mo - will report back when dark! Looking forward to your next post to learn more.
EH
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gets more interesting .. just spoke to local indy mechanic who also has a dsg A3, and he always gets what he calls an engine "flutter" effect on initial acceleration from stop, but not my flat spot. He's spoken to Audi techies and reckons it's a "feature" of dsg.
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brake lights do work, Screwloose
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EH
The brake pedal position sensor over-rides the accelerator's "fly-by-wire" system for safety reasons.
The twin-circuit pedal switches on these are very prone to failure. If the whole switch breaks, then the brake-lights fail too; but it's possible for just the pedal sensor side to fail on it's own.
The symptom of the engine idling but not responding to the throttle made me wonder about the pedal sensor.
However; it's warranty, so let the dealer find the problem.
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interesting stuff ... thanks - will report back when there is "result"
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Good result: prob seems to be now resolved - Audi had car for 2 days, replaced brake pedal sensor as "precautionary measure" (nice one, Screwloose) and "adjusted" both clutches in g'box. Car now far more responsive. Their plug-in fault check also revealed intermittent prob in one electric window motor (not noticed by me!), and they've ordered new motor .... "part's on back order, we'll ring you, sir, to arrange fitting when it arrives". Car handed back, washed and vaccumed. All under warranty - impressive service.
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right, time for update .. and more help needed, pse - perhaps Aprilia and Screwloose's expert knowledge could try and sort this one out. Audi dealer, in process of elimination, replaced brake pedal sensor and has now replaced throttle unit - but prob still there. Dealer seems perplexed, so before warranty runs out (Jan '08), any other thoughts, pse? To recap briefly, once or twice a day throttle doesn't "work" - revs stick and no amount of pumping throttle makes any difference for up to 4-5 secs, which doesn't sound long but, e.g. when pulling out of a junct car becomes dangerous. It can happen when engine warm or cold, under acceleration from rest or at speed and on level or incline. I can usually replicate "flat spot" when reversing up my steep driveway (when engine revs sticks at tickover). Most of time the engine's faultless and goes beautifully. So we have an intermittent prob which, of course, is nightmare for dealer (but for me too!). And BTW, no faults are showing up on plug-in diagnosis.
Bottle of best malt to whoever makes my Christmas with possible solutions to go back to Audi with.
ta ever so
EH
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EH
There's little tech data available on these; but I've a feeling that, unlike the on-off switch on the brake, the clutch pedal on these has a variable resistance [potentiometer] that tells the ECU exactly where the clutch pedal is - in a very similar way to the throttle one.
This brings in the question of a software glitch. Maybe the system restricts revs if it thinks that the clutch is fully down? Is there a software update available? Have they tried a new MAF sensor?
Does it have a DPF or soot trap in the exhaust? I wonder if there's a broken lump of cat rolling about in there and blocking the flow?
Frankly; the dealer is taking a terrible risk in giving the car back to you. If the worst happened; they would get hammered. They should give you a courtesy car until they either fix it, or buy it back and store it until it's out of warranty. [There's a lot of buy-back cars hidden away for just this sort of thing.]
Edited by Screwloose on 07/12/2007 at 16:50
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thanks for further input, SL. But
er, clutch "pedal" on dsg 'box...?
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EH
The circuitry lists a clutch potentiometer - but as to where they hide it on those......?
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ok, ta for that - am now in touch with Audi UK HQ who are going to talk to my dealer. I've made it clear I am not grumbling, as such, abt dealer - I just want it sorted after "process of elimination" seems to have got nowhere so far.
Audi Customer Service chap said that now prob is "registered" I need have no concerns abt investigation not continuing after warranty runs out.
PS I noted with great interest in another thread re dsg Passat, Aprilia's comments abt these 'boxes and the horrendous cost of rebuild and ECU replacement. Yes, wouldn't a 5-6 year VAG warranty be a brave but popular move!
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update at last, and a happy result:
Audi had car for 3 weeks, technician "lived with it" at my request and concluded the dsg 'box control unit electronics were not talking to each other properly, although no "fault" was signalled. Replaced unit (at who knows what cost) and all well now. Excellent service and new loan car provided throughout.
Thanks for all interest and suggestions.
Edited by Dynamic Dave on 20/01/2008 at 14:41
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