[Biturbos4] Throttle position sensor problem

Richard van der Hoff quattro at rvanderhoff.org.uk
Sun Oct 26 10:24:22 PDT 2008

Hi guys, and thanks for the suggestions.

The symptoms are exactly as you describe, Grant.

Brett Dikeman wrote:
> On Oct 26, 2008, at 11:17 AM, Grant Lenahan wrote:
>> 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.
> 1.Make sure to use throttle/carb cleaner, not brake cleaner, which could 
> destroy plastic bits and does not contain any lubricants.

Noted. I have to say, I've had the TB off and wiggled it about plenty, 
and it looked fine and in no way gunked up. Also I don't think my 
problem is never driving it at WOT (for better or for worse...). Still, 
it sounds plausible (especially after 170k miles) so I'll get hold of 
some carb cleaner and try as you suggest.

> 2.If you can get to the potentiometer, hit it with Caig's MoveIT moving 
> contact cleaner.  If it is an enclosed potentiometer, really get it 
> covered- some will work its way in to the contacts.  Actuate it a bunch 
> of times, then use compressed air to blow it clean, repeat once or 
> twice.  As long as the tracks are just dirty, it should work great 
> afterwards. If they're damaged, well...then you're kinda screwed, unless 
> you can find a very close replacement for the pot.

The pot does come apart and the tracks look fine. I've tried "normal" 
contact cleaner on them...

Do you have a link for MoveIT? I couldn't find it anywhere, including on 
Caig's website. Do you mean DeoxIT?

> Since gunk will affect the resting position of the throttle, it may be 
> beneficial to re-calibrate the throttle?

Tried that already :/.

Thanks again,


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