Is there any way to hook up a toggle switch that would just disable/enable the knock sensor?

I would ideally like to run the car with the knock sensor enabled and maybe the odd time with it disabled for testing purposes. I think if a toggle switch was wired into the knock sensor circuit then it would be a lot easier than programming / switching chips.

Has this been done and / or can it be? Would this set a code?

 

Of course a switch can be installed. I simply disconnected the knock sensor wire in my car. No codes. It's been disconnected for years. It may pay to read your FSM to be sure how your ESC works and what causes a code to be set. If a code is set, and it goes into the limp home mode, your purpose will have been defeated. From what I've read on here, not all cars are like mine.

RACE ON!!!

 

I had problems with bad connection on knock sensor a while back. But engine would run really bad with it disconnected.

 

I do not want to simply disconnect it. I would want to be able to toggle it on or off at my discretion. Can this be done and/or how difficult would it be?

 

yes it can be done, I have it in my 90.
I did it like 6 years ago so I dont remember the specifics.
I did it after I modded my engine and thought I had false knock.

I have a switch that is goes to a resitor, I cant remember the value.
anyhow, I can switch to bypassed of reading off the sensor in seconds.

just found this
http://forums.corvetteforum.com/show...m_id=48&arch=1

this sounds familar to me. I am 99% sure this is what I did

 

I guess I should explain a bit more.

The resistor allows you to run without the knock sensor,and not set any codes.

I think my switch has 3 terminals. I ran the computer part of the knock sensor wire to the middle.

I ran the resistor grounded to the bottom and the line going to the knock sensor to the top.

I flip the switch up and I am bypassing the knock sensor.
I flip it down and I am running off the knock sensor.

I mounted my switch in the cup holder area. when it is up, bypassing the KS, the cup holder door sticks up a little, this way I know when it is bypassing, and is not left accidently on bypass.

 

Exactly what Bill said below can be done with a simple switch and resistor of the right value.

However knock is really something in the later years that people have gotten carried away with - since the advent of the sensor itself.

Knock is something that you want to avoid, but it takes a hurrendous amount of it and ignorance on the part of the driver to not hear it and keep driving it to actually do damage.

Pre-ignition, on the other hand is and will be devostating upon first encounter and will detroy a motor in a matter of a few revolutions. This can be caused by spark scatter in the distributer or glowing embers in the combustion chamber that ignite the air/fuel change way too soon and the piston is them slammed into the exploding charge that is trying to force it back down in the opposite direction.

But the two are completely and totally different.

A knock sensor will NOT stop pre-ignition, it will stop knock. Or cause false knock. The knock sensor itself is tuned to a specific frequency. If you bore out your motor, change cranks or add rocker arms you have now effectively thrown the engines normal operating frequencies off, and could be now entering into the frequencies that the knock sensor now picks up.

On my 406, I used to be able to sit at idle with the motor at 900rpm in park and the knock sensor would simply count up 1.2.3.4.5.6.7.8.........Now obviously this was not real knock, just my motor happened to now be operating in the frequency the knock sensor was tuned to.

This also work in the manner that few discuss. If you have changed the operating frequency that the motor works at to where your causing false knock, you can almost be 100% sure that your knock sensor will NOT pick up real knock - the frequency at normal operation was shifted, the knock frequency of this motor is also going to fall out of its normal operating range.

Having said all this the knock sensor itself is really a useless sensor now that you changed your motor. As a result of these reasons, this is why you don't see many people at the tracks running these sensors on EFI cars. Your really wasting your time trying to work around the sensor and trying to find the sources of your false knock.

Just my .02

 

When did you start getting too much knock? There wasn't much knock on the uni file you sent me.

Jeff

 

Jeff, I'm getting knock retard at WOT. It's pulling a user defined maximum 7 degrees of timing at this point.

I simply want to still effectively use the knock sensor but to be able to toggle it on/off to see how much performance is lost when timing is pulled by 7 degrees.

Thank you all for posting and that was an interesting read ski.

 

I could see using something like that at the track. It would be like a knock sensor ignore switch.
So you can ignore the knock for say...12-13 seconds at a time.
Off topic:
I put my stock chip back in and my knock is nowhere near as bad as it was. Pretty minimal actually but it still retards the timing when it's present. This was in the fall before I put it away for the winter. You still driving yours?

 

Jeff, I've had mine away for a month or so now. Less knock with the stock chip? Maybe too much timing was added to your performance chip?

I'm thinking of removing like 5 degrees timing too see what that will do as well.