Knock Sensor Performance Modification

[mechtech]

Many newer cars have over sensitive knock sensors, and are too picky. They are retarding timing when it's not necessary. They pull 6 degrees or so, on some cars.
I belive that a knock sensor is a good thing, but should be for unusual circumstances, like when very hot or a tank of bad gas.
It should not be used for your base tune, which in practice, many are.
After hearing about good results in other forums, I took mine out, insulated it, and tie wrapped it up with the wires connected [so no codes would be thrown].
Wow! Instant knocking when I test drove it. This means there was lots of timing advance that was being cancelled out. I filled the tank with premium [my performance computer and Superchip require this, anyway] because I had mid grade 89 in there. That fixed the knocking.
There is a lot more power, and smoothnesss to the power band.
On stock vehicles, you may not have to use better fuel, or maybe go from 87 to 89.
This no cost mod really wakes up engines, but you'll have to see if a fuel upgrade is needed on your particular engine, and if it's worth it to you.
For a tuner/enthusiast, try this out, to get all you can out of your spark map in your computer.

 

[porcupine73]

Interesting mod! I'm keen to maybe give it a try. Just curious, had you run the vehicle on premium fuel previous to pulling the knock sensor? Just wondering how much difference the premium fuel alone made vs. pulling the knock sensor.

 

[adam123]

I always just run premium fuel. If the knock sensor isnt enaging (Like when running premium fuel). Wouldn't it have been better to leave it on so if you did get bad gas it could compensate ?

 

[DriveHard]

I did the same mod when I owned my Nissan Spec-V. I noticed much better throttle response and more consistant power when it was warm. It only knocked once when I was in the backwoods of West Virginia and HAD to buy regular gas in some small town in BFE. Had to drive nice and slow until I made it back to civilization.

 

[mechtech]

This is a common mod on performance forums, and the knock sensor is disconnected on many performance chips.
Sure, a proper knock sensor would be great, but the state of the art is that they don't work well. They are TOO safe.
Once again, I'd rather tune the car with programming, than with a jumpy sensor.
I want the sensor for special occassions.
I did try premium, but heard no knock with mid grade, so I used mid. The sensor is not only hearing spark knock, but other ambient vibrations, and is pulling timing, making the power curve wavy and less then maximum.
On some days, the premium did feel better, though, with the sensor plugged in.
Now, there is no doubt about a power increase.
If you get bad gas, do what everyone did for decades - drive easy until you can refill.
Bad gas isn't a real concern. It is rare thing, really.
$0.20 cent a gallon more for me, is $100.00 a year, or so. I probably am geting a little better mileage, now, anyway.