90 MAP system Code 43 help needed

[Walter Sherwin]

Was there any work done to the vehicle, or were there any other
changes/events, which may have coincided with the onset of this problem?
Perhaps some service work, or perhaps a component change, or perhaps even a
cal change?  Are you now running a better fuel than before?

The MALF 43 algo is pretty straight forward.  Part one usually peers out
into the world to determine whether a functioning ESC sensor is dangling
within the circuitry.  Part two usually advances the timing slightly to look
for self induced knock.  If the algo does not sense knock as a result of
this, it will try usually once more and then set a MALF code if it does not
sense knock the second time around.

There are discrete cal thresholds that define when and how often "Part Two"
plays these games.  Usually at a minimum they are:  coolant above X, elapsed
test time GT X, ESC counts less than X during the test, box not in
diagnostic mode, box either in PE mode or in non PE mode but TPS GT X, other
MALF codes not currently active, RPM GT X, MAP GT X, coolant LT X, and a few
others.  What cal package are you running?  Perhaps someone can fill in the
blank "X's" for you.

ESC sensors are physically affected by installation torque, overtorquing,
and gunk thickness on the threads.  It might be a good idea to manually
determine that your ESC sensor has not gone deaf.  With engine running, and
a scan tool hooked-up,  try rapping the block with something heavy and
metallic.  If all is well, you should see a blip of ESC count activity on
the scan tool each time you whack away.  If not, then something is surely
funny within your ESC setup.  This is best accomplished with an assistant.


Walt.





>
> Also, might need more timing added during the test.
> You can get to the stage of everything perfect and do EST codes, cause the
> engine is not very detonation prone.   In addition to items mentioned.
> Bruce
>
> From: "Programmer" <nwester at eidnet.org>
> > Bad knock sensor, RFI from ignition wiring (make sure the ignition isn't
> > within 6" of the KS wiring circuit--I can send you the actual GM
> diagnostic
> > sheet on this.
> > Lyndon.
>
> > From: mike.hoenes at ncmail.net
> > > I need a guru on this one.
> > >  My ECM is setting a code 43 - which on this setup is indicative of
> > something wrong
> > > with the Knock Sensor circuit.
> > > I have replaced the sensor, the ECM, the distributor pickup, checked
all
> > the wiring,
> > > and I have checked all the "sense" voltages in the Knock Sensor
circuit.
> > All the
> > > voltages indicate that everything is normal and that it should not set
> the
> > code.
> > > Does anyone know of another reason it sets a code 43?
> > > The system worked fine for about 6 months beofe it started setting the
> > code.
> > >
> > > TIA
> > > mike
> >


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