Can anyone help ? audi a6

[mmm777]

HI everybody , I got audi a6 1.8 T auto, car is in perfect condition, on last trip what was over 4000 miles , on way back I find , like car jerking when accelerating, but only when I push pedal really hard, but still got power, on normal acceleration is everything just fine, I already checked MAF - unplug, cleaned, try new one, but still is there, I got diagnostic cable and VAG com diagnostic, I checked everything no error code. I fitted new N75 valve, clean throtle body, checked hoses for leaking, clean turbocharger boost pressure sensor TC, I can't find anything wrong, what can I overlooked, missed?

Thanks a lot for any help...

[Ben]

Sounds like you know your way round the engine. Did you check the condition of the spark plugs for cleanliness and that the spark gaps are correct. What about the fuel filter, if its dirty or obstructed fuel flow may be affected when the engine needs it most, i.e. When under acceleration.

[mmm777]

Hi GOLFMK5GTTDI, thanks for advise, spark plugs are new and when was fitted in servise I believe they setup corectly gaps, but I will check, fuel filter is new, was new before this trip, car got big service, I don't believe can go dirty so quickly, just after aprox. 3000 miles after fitting???, but I will check this part too, thanks.

mmm777

[cbrpaul]

A few ideas for you m8 !

When you accelerate hard you put max demand on the ignition system at this point

I would check ,the leads and coil pack , and all connections

When its dark open bonnet get a m8 to rev engine and look for spark arching/leakage , you will see nice white flashes if faulty

One other thing , one of my old cars a few years ago , was jerky on hard acceleration but only when the engine was well warmed up , it was perfect when cold

Turned out to be a faulty crank sensor !!!


good luck

[mmm777]

Hi cbrpaul, today I checked all advise what you give, no result, everything is just fine..., no spark leakage, or faulty crank sensor, already I checked what advise me GOLFMK5GTTDI, but everything, spark plugs are new - and gaps are perfect, fuel filter is clean, already fuel pump working properly.., what I just thinking is maybe TC - Turbocharger wastegate regulating valve..., because car got power, and boost too, but this jerking starting around 4000 rpm, but sound like loose boost , make new boost , and loose and again..., its like slow jerking..., I try check pressure on TC if its working properly or not with pressure gauge, and I will see.

Thanks a lot.

[mmm777]

Hi everyone, problem fixed, was turbo actuator, spring inside was broken...

[Peter D]

Glad it's fixed. May I ask exactly which cable you bought and where and at what cost did you buy it. Regards Peter

[mmm777]

Hi Peter, my part look like this :

http://www.forgemotorsport.co.uk/con...duct=FMACVAG02

what i know there is no cable.., in my old one was spring broken inside, and make hesitation under acceleration, if this help...

[Peter D]

No No, I was asking about the Diagnostic 'cable' to use with a laptop and Vag-com SW. Regards Peter

[mmm777]

Oh, sorry, I bought from ebay: http://search.ebay.co.uk/search/sear...tle=vag++cable, you can choose which you need, I think my was OBD II and was around 15 £ incl. delivery, and diagnostic software I download from there : http://www.ross-tech.com/vag-com/download/