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B5 a4 tdi 90hp 2000 won't start. Fault code 17656. Please help!!

Discussion in 'Diesel forum' started by Scottyb5tdi, Jan 31, 2012.

  1. Scottyb5tdi
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    Scottyb5tdi New Member

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    Right. Where do I start. I recently purchased a 2000 a4 tdi 90hp with a snapped aux belt and broken tensioner, so I set about stripping out the old belt as it had wrapped around the bottom pulley, also the bottom timing cog.
    After I had cleared the old belt, the engine turned freely so I tried to start it but to no avail. so I checked the timing and it had jumped, so I set the timing up and built the front end back up and tried to start it, it eventually started on easy start and it sat ticking over perfectly, I tried revving it gently and all was good so I went to set off for a run and the car drove superbly until I brought the turbo In, it boosted perfectly but when I let off, it spluttered and cut out!

    It then wouldn't start for a while but eventually did, It sat ticking over perfectly but as soon as I tried to rev it over 3k ish it would cut out and take ages to start again. So I then took it home and changed the filter as it was due a service and I thought it might be clogged. After I changed the filter it won't start! At all! Even tried towing it but nothing, just smoke! I've had my mates vag com on and it said 17656 injection start regulation control deviation 18062 please check dtc memory of instrument cluster.

    Can someone please help? I'm stuck now!
    Much appreciated. Scott
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  2. Scottyb5tdi
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    Scottyb5tdi New Member

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    I take it no ones very technical on here
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  3. PAULF
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    PAULF Active Member

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    Try checking on the RossTech site, they have a list of codes and possible courses of action there.
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  4. adamss24
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    adamss24 Well-Known Member

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    It sounds like the timing is out...
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  5. Scottyb5tdi
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    Scottyb5tdi New Member

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    If the timing was out, wouldn't it have not started at all? I had it running for ages, sweet as a nut but if I revved it hard it would run out of fuel and cut out? I've checked the fuel lines, filter and pump for blockages and it's all clear. I'm thinkin it's either the n108 valve or g80?? Thanks very much for the replies and help. It's much appreciated.
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  6. adamss24
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    adamss24 Well-Known Member

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    Check the pump timing as it's out ! Get someone to do it for you if not savy enough !
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  7. Scottyb5tdi
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    Scottyb5tdi New Member

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    I can't understand how it ran after I'd timed it up but now won't? I haven't touched the timing or the belt hasn't jumped since I've had it running. Is the pump timing set by putting a pin in the pump pulley, through the smallest hole and into the pump?
    Thanks scott
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  8. adamss24
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    adamss24 Well-Known Member

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    Yes and the cam and crank need to be at TDC otherwise the engine won't start however if 1 tooth either way it might start on easystart or bump start but won't start on it's own. If you take the trouble of taking the belt off i would remove the cam as well and check the lifters are all level with the deck and no damage from valve to piston contact . If any lower than the rest then it's a bent valve and the head needs removing. Don't chance-it, seen it before and the valve dropps within a few thousands miles wrecking the engine in the process ! Hope i don't sound harsh but i've rebuilt dozens of them engines and i am quite bored to write all the info again, you can use the search function- there's plenty posts online about 1.9Tdi rebuilds- google is your friend !
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  9. Scottyb5tdi
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    Scottyb5tdi New Member

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    Still not working after being timed up properly. I found the injector leak off pipes were leaking and obviously sucking in air so I've replaced all of them and although it's better it still splutters and cuts out if I rev it hard.
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  10. Scottyb5tdi
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    Scottyb5tdi New Member

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    Forgot to mention when I towed it to start it won't start till I flick the ignition on and off then it quickly starts and revs absolutely fine. I can hold any revs constant, would sit at the redline no problem but if I was to let it off quickly from high revs it cuts out or if I rev it high and fast it makes the dash lights click and flicker, then cuts out when I let off. Also It won't start off the key so with it not bumping untill I flick the ignition on and off I'm thinking maybe it's something electrical??
    Thanks in advance for any help.
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