Re: Yoicks! Problem!

[steveb@falcon.kla.com (Steven Buchholz)]

> My car all of a sudden will not pull more than about 1200 rpm.  This
> happened ALL OF A SUDDEN!!!!!  (The day after we cleaned the engine.)
> Any more than this and she charges and stalls, charges and stalls, but
> actually the charges aren't really charges cuz there's no power.  It will
> idle along fine in 1st or second gear as long as you don't put in any
> throttle.
> 
> We disconnected the connecter at the pressure regulator on the fuel
> control unit and it runs fine!  So the question:
> 
> Is the pressure regulator at fault?  Is the thermo time switch at fault?
> (My BF is dictating this question to me, by the way, I didn't come up with
> these terms on my own).
> 
... let me preface my comments with the fact that I'm not completely familiar
with the FI system on the '88 80Q ... but I know how it is supposed to work.  

IMO since the system works when the fuel pressure regulator is unplugged
that it has not failed ... it is more likely that it is being fed an improper
control signal.  

I doubt that the thermo-time switch would cause the symptom you describe.
The TT switch controls the cold start injector.  Failure can cause several
different kinds of starting/running problems when the engine is cold, but
in no case would unplugging the FPR fix them.  

My guess is that the control unit is receiving some faulty signal ... 
possibly as a result of your cleaning the engine.  Check all of the sensors
and switches mounted on the fuel distributor, engine, manifold, radiator, 
etc. to make sure that everything is plugged in correctly.  If you don't
have a Bentley manual available it might be best to take the car to a 
Bosch FI repair shop.  If you can find a Bentley and have the proper tools
you'll probably be able to isolate the culprit fairly quickly.  Your car
probably has some sort of OBD capability (on-board diagnostics), do you
notice if the check engine light comes on?  If so you can read the error
code out.  

I can't say that I'd recommend running your car for a long period of time
with the FPR disconnected.  I'll bet that right now you're not into much 
to fix the problem.  You might end up buying a new cat if you try running 
open loop for too long ...

HTH! and I hope that you can get things together for the event!
Steve Buchholz
s_buchho@kla.com
San Jose, CA (USA)