RE:'88 5000CD TQW engine knocking

[Russ Southelrin <russell.s.southerlin@lmco.com>]

Andrew,
Even though you say no warning lights come on I think you should still
try to pull the fault codes right after this happens (or even when the
car is running O.K. for that matter).  If the engine is pinging you
should at least get the fault code for ECU not able to retard the timing
enough (I forget the exact code off the top of my head).

If the pressure transducer/ECU had an intermittant open (or short) on
the signal and it was going to 0.0V then it would read 0 bar on the
boost gage and like P. Timmerman suggested you would not get timing
retard.

When this happens what does the boost gage read when the engine is off? 
It should read 0.8-1.0 bar with engine off.

Russ
87 5KCSTQ
Littleton, CO