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Tech Notes: |
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Knock Sensor Relocation
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WARNING
WARNING WARNING WARNING
WARNING WARNING |
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When FORGED PISTONS or any kind of
performance pistons have been installed in a fuel injected motor, you
MUST relocate the knock sensor.
Failure to relocate the sensor will result in
FATAL ENGINE DAMAGE.
The current location of the knock sensor is ideal for stock Toyota
engines. However, with the modifications to your particular engine,
which include forged performance pistons, this location causes problems.
PERFORMANCE PISTONS are noisier than other pistons and the knock
sensor picks up the noise as detonation or pinging. Upon sensing
this it retards engine conditions, such as cruising on the highway.
The retarded timing and excess fuel causes overheating on the exhaust side
of the upper piston ring land. Continued operation with this
condition will cause premature engine failure.
Removal of the knock sensor is not an option; this will cause the computer
to go into an open loop operation.
Relocate knock sensor by drilling and tapping on of the unused upper
bosses on the right side of the engine block. (See Illustration) Use
a .422 or 27/64" sized drill and a 12x1.25 tap.
PAY SPECIAL ATTENTION WHEN DRILLING THE BLOCK.
Don't drill any deeper than the current hole in the boss. By going to far,
you will drill through the block. Relocate the knock sensor to the
upper boss. Any questions? Call LC Engineering Technical
Department at 928-855-6341.
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Knock Sensor Relocation: |
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The 22RE Pro (forged piston) engines require relocation of the knock
sensor. Why? Here's the reason. The forged pistons create a
high-pitched knock when they are cold. The sensor hears this knock
and instructs the computer to take ignition timing away and add fuel
to the motor in order to combat detonation, which is not really
happening.
In order to prevent this, we relocate the knock sensor lower on the
block below the bore line. The sensor will still hear a detonation
on lean condition and react correctly, however, it is low enough on
the block to not hear forged piston's rocking. |
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Relocate the knock
sensor by drilling and tapping one of the un-used lower bosses on
the right side of the engine block. Use a .422 or 27/64" sized
drill bit and a 12mm x 1.25mm tap. PAY SPECIAL ATTENTION WHEN
DRILLING THE BLOCK. Do not drill any deeper than the current
hole in the boss. By going too far, you will drill through the block.
Now you can relocate the knock sensor to the lower boss. This is
shown in the attached photo.
If you use cast pistons in your rebuild, the knock sensor relocation
is not necessary. The cast pistons grow with heat faster than
forged pistons and do not rock in the bores.
Remember, removal of the knock sensor is not
an option: this will cause the computer to go into an open loop
operation. Not Good!
Any questions, give our tech line a call at 928-505-2501. |
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