re. Eng. Light only if boost is over 1.0-1.1 bar

[ben swann]

Jim,

I had this happen when the control line to my bypass valve slipped
off.  That would be on the same vacuum/boost circuit as the ECU control
line.

Engine was complaining a little, but could still get significant boost.

Here is a vaccuum diagram of the vacuum modifications to the engine,
which included the bypass valve.  It retains the original routing to
help you trace.

Serves you right for selling those wheels and tires to someone else
instead of dropping them off here in Annapolis ;-0

Umm, just kidding.  Check and see if a line popped off somewhere.
Bring it by here on the way back and we'll find it.

Ben

[Last night (rather this early morning) I was just about home after a 2
and a half hour drive from Washington, DC to South Jersey, I started to
get a check engine light only when boost went over 1.0 to 1.1 bar
displayed. The car ran fine other than the light coming on. Any idea's?
Would the wastegate freq. valve through a light? The light would stay
on from 1.0 to 1.1 bar all the way up to 1.8-1.9 bar. As soon as I let
off the throttle, the light would go  out. I'll trouble shoot during
routine maintenance today. Driving back and forth between New Jersey
and DC put the miles on the car pretty quick. The car is a 1987 5000 cs
Quattro with MC/1 engine. IA chip and an AAN wastegate for the
adjustable spring. The car has 227,000 miles.

Jim]