RE: '88 5000CD TQW engine knocking

["Buchholz, Steven" <Steven.Buchholz@kla-tencor.com>]

I think that the original poster is getting some excellent feedback on
this problem ... but IMHO one thing is being left out.  That knocking is
occurring because your ECU is getting a faulty input.  Knocking is not
often a good thing for an engine; if you must drive the car, try to keep
your foot out of it as much as possible.  Yes, it is true that the ECU
should be getting the feedback that the engine is knocking, and back off
the timing and then boost, but since you are noticing the knock it must
not be able to turn things down enough (perhaps Orin can comment on what
the code would do in this situation).  

If you want to try to track this problem down yourself, I'd recommend
that you "T" in a separate boost gauge as close as possible to the ECU
(which is mounted behind the kick panel on the right side of the
passenger footwell, in front of the door.  You should be able to remove
the screw that holds the cover down and pull back the front door seal a
bit to allow the cover to come off.  The ECU is in a little "shower cap"
... it might be able to get at the boost line without pulling the ECU,
or you might have to remove a couple screws to get the ECU out (hazy
memory here ...).  You'll need to watch the other gauge when the display
goes to "0" ... if both gauges read zero you've got a vacuum leak in the
line ... if the analog gauge says you've still got boost when the
display reads "0" you're going to need to repair or replace your ECU ...

HTH!

VdT!
Steve Buchholz
San Jose, CA (USA)