[cl] Knock Modules - LT1

[John Hess]

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
>
>