Knock sensor removal

[Gn Guy]

I have an aftermarket knock sensor installed in my '85. Is it ok to disconnect my factory knock sensor? If I watch my scanmaster at WOT I get a knock indication but nothing from the aftermarket unit. I do not hear any engine knock. I am running 94 octane with some VP C-12.
Any direction greatly appreciated.

 

[TurboRegal84]

Perhaps you can provide some more information?

The factory knock sensor is located on the back of the block. If you disconnect it there will be nothing in place to retard the timing if you have any knock, it will put on the Check Engine light, and Scanmaster will not be able to view the knock reading.

Keep in mind that most knock is not audible and if you can hear it that would be considered severe knock.

 

[Chuck Leeper]

Maybe the aftermkt sensor is not working??
Is the oem sensor torqued properly? Too tite, and it'll be really "goosey"...

 

[BRAD_PADGETT]

I have an aftermarket knock sensor installed in my '85. Is it ok to disconnect my factory knock sensor? If I watch my scanmaster at WOT I get a knock indication but nothing from the aftermarket unit. I do not hear any engine knock. I am running 94 octane with some VP C-12.
Any direction greatly appreciated.

I just resolved a problem very close to your issue. On my car, the transmission housing sticks up about a quarter of an inch higher than the back of the enngine. The knock sensor when tightened down touches the lip of the transmission housing thereby causing knock when at wot between 30-35mph and 55-60 mph. Hard shifts set it off as well. the solution was remove the knock sensor, reninstall hand tight and one half turn with a socket. This should leave enough clearence between the bottom of the knock sensor and the transmission housing. It is worth looking at. Brad

 

[Gn Guy]

I have had knock issues before and usually from low octane fuel. My aftermarket sensor seems to work as it would go to red right away plus you could hear the knock. I would then quickly take my foot out of it. When I upgrade my fuel octane I still get a visual sometimes but just the first green led lights up.
I have upgraded the turbo and have a ported throttle body and hear the turbo spooling a lot better.
I will look at Brad's fix as I have had the transmission upgraded.
My question still, is there a fix for the OEM sensor if you stop using it and use the aftermarket which I believe is a Casper unit.

 

[TurboRegal84]

The Caspers Knock gauge takes the reading from your factory knock sensor and displays it. If you remove the factory knock sensor the gauge will have nothing to read. In addition the engine will have no way of knowing to retard the timing when knock does occur.

 

[Gn Guy]

Many thanks for the info.