low power

[Jim Green]

--- Konstantin Bogach
<konstantin.bogach at morganstanley.com> wrote:
> Hi listers.
> 
> One of my 200q '89 has low power output.  Injectors
> new, fuel pressures
> are in spec, boost develops to 1.4bar at WOT, 1.2bar
> was seen when it
> had bad trottle switch which makes me believe that
> additional 0.2 bar
> are coming through WGFV.  No vacuume leaks, intake
> air temp sensor is
> good.  I check almost everything.  Except exhaust
> back pressure and bad
> valves and leaks in cylinders (which I don't know
> how to check).
> I have 2 questions:
> 1. What back pressure is considered good and
> acceptable?
> 2. What else I can check to narrow down  the problem
> debugging?
> 
> Thank you very much.
> 
> Konstantin Bogach
> 200q '89 (week)
> 200qa '89
> 
> P.S.  I have another question for 200 avant owneres:
> where is rear wiper
> relay? It is not in there where Bentley depicts it.
> That slot is empty
> (auxilary relay panel)
> 

E-brake?  Just kidding.  Sounds like something is
clogged like the CAT or air filter, but the full boost
reading would take a while to reach with one of these.
 You may have a stuck valve or bad leak-down in the
cylinders.  I think the thing to look at is if it's a
problem that just showed up one day and what you did
before that, or if has gradually gotten worse. 
Compression testers are ~$30 and are real easy to use.
 Just remove your plugs, ignition coil wire, and I
like to take out the fuel pump relay.  Make sure the
engine has been run for a while to get the rings wet
or else you may get bad readings.  Then hold the
throttle open and let it crank 5 or 6 times.  I think
you should see something around 150 psi? Maybe higher
or lower depending on elevation.  Could be the timing
is retarded, I mean retarding.  Is it Fri. yet?  This
would case a loss of power.  Bad Knock sensor?
Good luck,


=====
Jim Green
'89 90tq 
http://www.geocities.com/jeg1976/

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