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cold weather blues

Discussion in 'A6/S6/Allroad forum (C5 Chassis)' started by maxlbrown, Dec 12, 2007.

  1. maxlbrown
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    maxlbrown Deep Blue

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    [Dec 12, 2007]
    the ast two mornings my a6 has decided it doesn't like the cold between 1 to 2k rpm above this and tickover it seems fine.

    It seems to feel like theres either a lack of power or runs rough.

    Any ideas

    PS vag com is not showing any errors or DTCS. I reprogrammed the ECU so it thinks its an a4 this helped a little but hasn't really done much except reduce torque as i found before.

    any help i am thinking something in the cold start mechanism but on this do not know where to really start looking and poking.

    It has been serviced recently and was perfectly fine till monday night.

    Cheers
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  3. maxlbrown
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    maxlbrown Deep Blue

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    [Dec 19, 2007]
    Briefly the lack of power moved to between 1K to 2.5K to spread. took it to an indy changed the MAF.

    Improved but still not right especially cold any ideas please again tickover and over 2K ok but power seems lacking somewhere.

    I get the feeling this may get expensive.

    As i said nothing is showing on DTC or vagcom.

    Help

    Max
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  4. enda1
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    enda1 Member

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    [Dec 19, 2007]
    The coolant temperature sensor may be knackered and this might not show up on vagcom. I've seen on other threads that the maf and coolant sensor are the main reasons for rough running
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  5. maxlbrown
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    maxlbrown Deep Blue

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    [Dec 19, 2007]
    I have mentioned this to my tech he seems to think it may be leads. as 1 plug seems black.

    Well see if the leads dont work it will be a new sensor if any one can tell me where it is ill change it myself.

    Cheers

    Max
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  6. maxlbrown
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    maxlbrown Deep Blue

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    [Dec 25, 2007]
    right

    so far changed coolant temp sensor, maf no real difference

    tried new leads and plugs no difference, coil packs are ok as the sister cylinders are all fine. we seen to have an eratic misfire.

    nothing showing on vag com or other diag systems. i am now coming to the conclusion its untraceable and basically a get rid quick job.

    max
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  7. donvas
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    donvas New Member

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    [Dec 27, 2007]
    Try disconnecting the airmass unit on the airbox and see if you more power,note you will log a fault in ecu but you can reset it later.From the info you also might have a missfire
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  8. maxlbrown
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    maxlbrown Deep Blue

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    [Dec 30, 2007]
    the Maf has been tested and changed and the coli packs plugs and leads have all been tested and changed or changed and no different this is definitely worse till the engine warms up then its better but not perfect. Its as if its running on choke all the time like in the old days. iam suspecting its something in the cold start / running system. it starts great and ticks over fine its just when you get on the move. ps its drinking petrol hence the choke theory. 257 to a tank its getting worse.

    thanks any way
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  9. maxlbrown
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    maxlbrown Deep Blue

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    [Jan 7, 2008]
    I put the old plugs back in in and checked that the new ones where the same. ( they where) I also removed and cleaned the air temp sensor at the back of the engine in the inlet plenum. it was a bit black.

    I had already tried to reseat the connector before but cleaning seems to have done the trick no hesitation or misfires.

    So far the last two days its been perfect. i will swap the plugs back to the new ones some time to check and see if i got some faulty plugs or it was the sensor.

    M
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