Temp related low boost
SuffolkD at aol.com
Mon Sep 19 23:06:53 EDT 2005
Makes sense Taka, Alt sensor: thin lower boost to keep from overspinning
the turbo..................Good point.
Makes me think my alt sensor is fine..................
-Scott by BOSTON
> From: Taka Mizutani <>
> I experienced pretty much the exact same issue, with similar results-
> I don't know if your car is chipped or not, but anyway....
> With Lehmann stage I chipset, I would normally see 17psi with 19psi
> on 4th and 5th gear extended pulls. When I had an issue, I would see
> full boost until the engine was warmed up, then I would see a peak of
> 12psi with a very slow increase in boost to even achieve the 12psi.
> I replaced the MTFS, the ECU temp sensor on the back of the head, the
> plugs, plug wires, distributor cap and rotor, still no success. Finally, I
> out from my mechanic that the altitude sensor had failed- I don't really
> how this failure seemed to correlate with temperature of the engine, but it
> After replacing the altitude sensor, I never saw the problem recur. It's a
> rather odd
> thing, never documented by SJM Autotechnik, or in the Bentley, but that
> worked for
> me. I would go through the usual checks (VAG-COM is very useful to see what
> ECU values are cold and hot) in the Bentley before doing this.
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