Still Surging

Taka Mizutani t44tqtro at
Tue Aug 23 08:17:28 EDT 2005

Can you describe the surging in terms of what it looks like on your
boost gauge (hopefully you have one)?

With the Lehmann chipset in my old car, I would have full boost of
19psi in 4th and 5th gear, but it wasn't completely without hiccups-
stomping on the throttle in 3rd would result in a quick boost to
19psi, then an immediate dip (I think the ECU was pulling back timing
each time), then a more gradual climb (but within 1-2 seconds tops) to
about 16psi. Rolling on the throttle resulted in a much less
noticeable dip in boost- the car just felt a bit slower to respond, no
real feeling of loss of power, but the boost gauge told the whole
story- a moment of dip, then 16psi.

I've never experienced boost surging in the 200, I think it would be
the result of poor software tuning. I have experienced it in our old
A4 1.8T- max boost, then surging- back and forth from 12 to 15psi. It
would only happen in the winter with oxygenated gas.

Throttle position sensor- I don't know if you would have surging when
cold with a bad TPS, though.


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