Toyota: Corolla knock sensor? help please!

"Andy Weller" <getstuff[at]dsl.pipex.com> wrote in message
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The knock sensor is supposed to sense the pinging and tell the engine
management computer. If replacing the plugs fixed it for a while seems to
add weight to the carbon buildup (on the plugs ?) theory.
Does it use oil?

Jason

"Andy Weller" <getstuff[at]dsl.pipex.com> wrote in message
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Well I'm at aloss to guess any further. The plug thing should be pursued as
it does hold out a positive indication. If the pinging stops with a plug
change, examine the old ones for tell-tale signs like crud build-up.
As to the EMComp, it should be able to handle pinging unless it has gone
outside its range?? Philip?

Jason

Jason James wrote: 

Start with the ECM stored codes. This MAY -not- provide a
correction. If no stored codes exist, then you start looking for the
usual culprits.

-Ambient temperatures are too high for the octane used.
-Too tall a gear being used for conditions
-Cranking compression too high. This can be from excessive carbon
accumulations or ... the intake cam can be one tooth advanced from
"correct" position (closes intake valve earlier than spec).
-EGR. This is the bugger that will cause light to medium throttle
"pinging" when it becomes inoperative, even moderatly compromised. In
some cases, there will be a back pressure sensive valve that controls
vacuum reaching the EGR valve itself. Other times the passage
feeding exhaust gases to the EGR valve becomes restricted or clogged
solid. A factory manual will detail proper testing of both valves
and/or any ECM controlled solenoid in the EGR circuit.

The matter of spark plugs causing "pinging" is doubtful.

--

~~Philip

"Never let school interfere
with your education - Mark Twain"