Scanner problems

[T Hergen]

On Tue, 30 Jun 1998, Bruce Plecan wrote:

> From: Jason Weir <jweir at worldnet.att.net>
> Subject: Scanner problems
> 
>  Another problem was I getting knock counts almost
> >constantly at idle, it would go from 0 to 255 in about 10 seconds and
> >then start over, until that is that I disconnected the sensor.  the
> >reason for that I guess is because the sensor is for a chevy 4.3 V6 and
> >its on a Jeep 4.2 I6, different frequencies? 
> 
> Depending on the BCC some do that, try a different BCC.
> 
> well any ideas on that one?
> >maybe using the stock jeep sensor, think it will work with the GM stuff?
> 
> Dangerous quessing here.

My '92 4.3L vin W (as opposed to vin Z, the one without the balance shaft) 
has two knock sensors wired in parallel.  There are different flavors of
the 4.3L vin W that require different calibrations.  One service note
states explicity (quoting from bulletin no. 23-61-11, referring to the
flavors of vin W 4.3L motors)  "Without the correct calibration MEM-CAL,
the engine will detonate."  Of the two vin W 4.3L motors I know about, one
has needle bearing (early motors) and the other has sleeve bearings.  The
needle bearings are more noisy resulting in the need for different knock
calibrations, I think.

The knock sensor locations for the vin W for more recent motors have
changed as compared to my '92 motor.  This will probably affect the knock
sensitivity (and required "calibration").

This info doesn't fix your problem, but it may help you figure out what
to look at.

Tom