just like the topic states. how do i disable the knock sensor. BTW i have a lt-4km.

Thanks

 

I'm sure a tuner could take it out for you.
If I may ask, why do you want to disable it? Since you already have a LT4KM, any knock retard should be from real knock. If you get rid of it completely you could get real knock and your engine wouldn't even notice, could have some bad effects. I would recommend knock sensor "desensitizing". I'm sure pcmforless would be able to take care of that for you. It would be better insurance for your engine, and it won't cost you any hp, that is unless there's already something wrong that's causing real knock, but then of course you need to take care of that.

 

just because he already has a lt4 km dosen't mean it could be false knock, i have the lt4 km and i am seeing almost the same amount kr and it can't be real as i have a fairly stock car and ALWAYS run 93 octane gas, i may have an exhaust leak so we'll se when i put my headers in.

 

^^^^

 

There are online guides to knock sensor "desensitization".... desensitise it far enough and it will effectively be eliminated. I think Brent Franker has the procedure on his tech pages, or maybe a link to it. You could just substitute a 4.5Kohm resistor for the KS, running the resistor between the single wire that goes to the sensor and a good ground.

Be sure you "want" no knock sensor. You are losing some valuable protection. On the other hand, if you have a good "hands on" dyno tune, the risk is minimal.

 

Thanks Fred,

After a little intuitive thinking (and manual consultation), I figured it out. I don’t want to disable it permanently, just for a little testing. I have some false knock that I am trying to troubleshoot.

JR

 

It's very easy to do in the PCM. Mine has been turned off for years.

Rich Krause

 

I also have mine completely disabled through the PCM.

 

what benefit does this have ??

 

When the car senses knock it retards the timming as much as 12 degrees, and then adds that timing back in very slowly. A lot of the time this knock it hears is false, and taking away timing kills power. If you disable it it takes the PCMs abilitly to retard the timing away.

You can actually see knock retard on a dyno graph.

 

I gave up trying to find the false knock on mine. It was pulling a lot of timing, I gained 40rwhp by disabling the KS. There are good reasons not to do this for many, so don't do it unless you know what you're doing and are prepared for the consequences if you screw up.

Rich Krause

 

I was trying to find the source of false knock myself, but with no success. Loud exhaust, pullies and other misterious rattles..., so I just completely eleminated it, AFTER I made sure it was false knock with race fuel and the stock tune loaded up.
You can use a 4.5kOhm resistor, but I had some MSD RPM pills laying around, and measured them with a voltmeter. It turned out, that the 5400 RPM pill has around 4.52k Ohms, so I just soldered a leg to the blue single wire that goes down to the KS, the other leg to a nitrous ground wire. Works fine, no KR problem whatsoever
Let me know if you need pics...