[s-cars] Re: the bucking S4 part 2

[William Noland]

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Chris -
Sounds to me, that you turbo is overboosting -- have you pulled codes
yet? If you've never done this, see
http://www.sjmautotechnik.com/ecuf20v.html#fault. If the turbo
overboosts, the ECU will shut things down -- NOW. I had the problem a
couple of times a year ago or so. Pulled all hoses and checked for
leaks. All good and problem went away. Did it again a couple of weeks
ago. Pulled off the freeway and re-started the car (the ol' reboot) and
all was fine. No problem since. When overboosting, the car pulls like a
freight train, then......POW.....the ECU shuts things down. If you keep
your foot in it, it will buck. Easier acceleration is no problem. The
fault code you'd expect to see is:

2224 (Blink Fault Code), VAG1551/2 Fault Code Number 00544
Over boost condition
Waste gate or pressure hose, Waste Gate Solenoid/hose problem

Bill Noland

>There have been many theories and suggestions thrown out regarding my
>"bucking" S4. The most common are check the moisture trap and change
>the spark plugs.
>
>Some backgound information,I jus replacedmy hoses with Samco hoses,
>could a boost leak be causing this? Autosport Werks has suggesttted hat
>it is a boost or vacuum leak.
>
>What I described as bucking is like the engine losesal power
>and the nose of the car dives. If I let off the accelerator and
>slowlyaccelerate I am fine, unless I mash the throttle down again in
>which
>case I lose all power again.
>
>I started driving this morning and the car responded normally, as both
>the car and ambient air temperature warmed up the bucking returned.
>I have recently realized that if I accelerate slowly the bucking
>doesn't happen, it is when I mash the throttle down to accelerate
>quickly that the bucking happens. When I am in third gear it happens
>around 4200rpm, second gear it is around 3800 rpm.
>

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