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Re: Boost gauge problems



Earlier, Taka Mizutani wrote:

> Hi listers,
> I have a VDO boost gauge in my A4 1.8T. I recently removed the gauge to
> paint the gauge housing, unhooking the two electrical wires and unscrewing
> the vacuum line. Ever since doing that, I get a much lower reading.
> 
> Is there a "recalibration" or some sort of reset necessary when reinstalling
> the gauge? I checked for leaks, and I don't seem to find any leaks. The
> line has a threaded coupling that is sealed with Teflon tape.
> 
> For whatever reason, I think the gauge is reading about 5 psi low- I get
> about 22 vacuum at idle when I used to read about 20, and max boost now
> only goes to 15 when it used to overboost to about 20 psi.
> 99.5 A4 Avant 1.8TQMS

Check that the needle reads exactly zero when the engine is shut off.
Some of the VDO vacuum/boost guages have a bezel that's fastened to the 
instrument face, and the bezel is loose enough to turn by hand.  Thus
turning the bezel moves the zero setting of the needle, since you are
moving the guage face with all the markings.  I've seen this in the 
VDO Cockpit series guages that were being sold pretty cheap by some 
of the discounters.

    - Charlie


 Charlie Smith   charlie@elektro.cmhnet.org  614-271-1418  
 http://elektro.cmhnet.org/~charlie/  Columbus Ohio   USA

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