[cl] Knock Modules - LT1

[David Piper]

Please tell more about knock sensor installation.  I have just added MSD
knock alert to my custom 280Z turbo test mule and it seems too sensitive,
indicating knock with slight application of throttle under load.  There is
no audible knock under these conditions.  The sensor threads had orange
coating like Hi Temp RTV.  I installed via 1/4" NPT to 1/4"-20 THD adapter
to block high near head between cyl 4 and 5.  Is there preferred method?  I
have fabricated hose clamp with nut to mount sensor on customer's car on
Dyno as warning.  This may not work, since difficult to calibrate.  What do
u think.

Thanks

TurboDave

At 09:14 AM 9/25/98 -0500, you wrote:
>Actually; if you want to decrease the sensitivity of the knock sensor, you
>simply remove it (drain the coolant, first), wrap a layer of teflon tape
>around the threads and replace it.  Start with it just firm and tighten it
>(increasingly) until it actually detects a quarter (or other metal object)
>tapped on the block near it.
>
>If it has EVER been overtightened, I will detect all sorts of noises as
>knocks.  If undertightened, it may never detect a knock.  I don't recommend
>running without it, even if you can find unleaded AVGas.
>
>At 09:48 AM 9/24/98 -0500, you wrote:
>>H Villemure wrote:
>>> 
>>> Simply replace the plugs for one or even 2 ratings hotter units... do
>not let
>>> the engine knock more than 5-6 sec. I destroyed a rod bearing doing a
>similar test.
>>> 
>>> I would very much like to know the basics of how a knock sensor works? I am
>>> new to the list and also to microcontroller design at all. I have
>everything
>>> to learn in this area!
>>
>>A knock sensor is basically a piezo-electric microphone.  There is a
>>circuit, called "ESC" in GM cars, that listens to the knock sensor and
>>signals the ECM if knock is detected, then the ECM retards the
>>ignition.  I don't know if anyone knows for sure what's in an ESC
>>module, but it seems pretty likely that it's just some sort of
>>filtering.  Someone with a signal generator and a scope could figure
>>this out???
>>
>>--steve
>>
>>
>>-- 
>>Steve Ravet
>>steve.ravet at arm.com
>>Advanced Risc Machines, Inc.
>>www.arm.com
>>
>>
>
>