200q20v stalling

Henry A Harper III hah at alumni.rice.edu
Fri Jun 2 20:41:54 EDT 2006

> I have a stalling problem that appeared litterally "overnight", a
> few weeks ago, and now is a regular nuisance.
> When either accelerating or decelerating and depressing the
> clutch to shift, the tach will drop through idle and the engine
> will stall.  There is never any stalling at idle (at a stop
> light, for example), and reving the engine at a standstill will
> not cause this condition.  Also, this problem does not appear to
> be engine temp related.  If there is enough motion of the car,
> releasing the clutch will restart the engine.  Or if this occurs
> while coasting to a complete stop, the starter restarts the car perfectly.
> But, in a typical thirty minute trip around town, the car may
> stall ten to twenty times in this manner.

Classical symptoms of failed bypass valve - what's the offical designation,
overrun something or other? See sjmautotechnik.com

> Also, there is a another (unrelated??) problem that's been around
> for a while, that appears to be boost related.  When "punching"
> the throttle under conditions when max boost are expected, the
> engine appears to cut-out as though the ECU may have sensed an
> overboost condition.  Reducing the accelerator a bit clears the
> problem.  The car has been chipped, but has an unmodified ECU.
> The panel boost gauge shows 1.4 to 1.5 when this occurs.

I'd like to know how the car is chipped without modifying the ECU. Do you
mean that the trip computer (boost display) has not been modified? From what
vendor was the chipping procured?

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