[Biturbos4] Throttle position sensor problem

[Mark R]

Grant's got it right.  I use fuel injection cleaner (basically carb
cleaner).  WD-40 will cause more buildup over time.

Clean it, re-adapt the TB (060).  If cleaning doesn't work, you'll have to
replace the TB ($$$).

FYI- With VAG-COM you can watch both sensors.  They should be linear and
work in "opposite" voltage directions.

Mark Rosenkrantz

On Sun, Oct 26, 2008 at 5:30 PM, Grant Lenahan <glenahan at vfemail.net> wrote:

> For the record, i used gummout carb cleaner which is much safer ( i
> believe).
>
> As a lubricant, WD40 is pretty bad. never intended to be a lubricant,
> it was developed as a water displacement agent in a light evaporating
> oil carrier. Hence its designation, "WD". I'd prefer something like
> super lube.
>
> Has anyone considered the virtue of "dry" lubricants that will not
> contribute to sludgy buildup?  Several companies sell aerosol dry
> lubes.... just wondering.
>
> Grant
>  On Oct 26, 2008, at 4:24 PM, Tony Hoffman wrote:
>
> > Richard,
> >
> > I've also dealt with this on customer cars, but never a v6tt. I've had
> > to clean the TB's on the 1.8T's and the 30V 2.8 and 3.0's. Do it just
> > like Grant described. I use Brake parts cleaner, then WD for a
> > lubricant. However, if you use brake parts cleaner, be very careful
> > where you spray it. i can melt/eat certain sorts of plastic. Only
> > allow it inside the throttle body itself.
> >
> > Tony
> >
> > On Sun, Oct 26, 2008 at 10:17 AM, Grant Lenahan
> > <glenahan at vfemail.net> wrote:
> >> BTDT on my 2000 S4.
> >>
> >> here's what I found.
> >>
> >> The typical fault you will get is called "epc" and a light should
> >> come.  epc is electronic pedal contgrol, or drive by wire.
> >>
> >> When a fault in the fly by sire system is detected the system goes
> >> into limp mode, which you experienced. It was happening to me every
> >> day. It resets with an ignition cycle.
> >>
> >> What i found is that the throttle butterfly, which is controlled by a
> >> stepper motor, slowly builds up crud inside the TB, much like an old
> >> carbon composition potentiometer in a hifi. I posited that thsi was
> >> the case, and tried the same old cure:
> >>
> >> 1. clean with carb cleaner by spraying inside the TB
> >> 2. loosen/clean the TB inside by exercising the butterfly completely
> >> through its angle of motion, several times, quickly. This creates a
> >> wiping action.
> >>
> >> It worked.
> >>
> >> You can infer that one of the problems I had run into was that teh S4
> >> basically had too much power for normal driving, and i almost never
> >> went WOT.  So junk built up.  Its another case of cars must be driven
> >> as intended, at least occasionally.
> >>
> >> Hope this helps,
> >>
> >> Grant
>
> Grant Lenahan
> glenahan at vfemail.net
> (201) 602-4702 mobile
>
>
>
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