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relocated knock sensor..Amazing results


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My 98 O/B wagon has been slower than a dog for over a year. Even on slight grades with the cruise control on,(set to 65mph), it would downshift just to stay at 65. when loaded up with the kids, dog, and all the other stuff, it could hardly get out of it's own way.

I did the knock sensor relocation thing yesterday and VOILA !! It's like I'm driving a brand new vehicle.

I relocated the sensor to a small metal tab at the back of the motor close to the firewall and unhooked the battery for 15 minutes to reset the ECU.

The change is dramatic...I'm thinking that because my car has 300K+ on it, and that it clacks like a Kenworth ,all the time, the sensor thought it was knocking and was backing off the timing....or maybe the sensor had simply crapped out.

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that must be a good feeling!

EDIT/CORRECTION: this only applies to older vehicles since the knock sensor mounts differently....

on an old XT6 i had years ago i had some running problems that were cured by addressing the knock sensor as well. i didn't move it, but i wrapped the sensor threads in a bunch of wraps of plumbing thread tape - probably 12 or so wraps of it. car ran noticeably better. in your case the engine is making noise so that probably wouldn't work. maybe in some cases the knock sensor could have bad threads and rattle around in it's insert somehow?

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I relocated the one on my mom's 98 last week as well. It was having the came symptoms.

 

I believe hers to have been an overly sensative sensor. Relocated it and bam... Back to its old self.

 

Gary, I would say you are correct for the ea/er knock sensors. But the ej/eg sensors don't thread into the block themselves, rather have a 12mm bolt that threads into the block to hold them in.

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It is nice the know about that mod. Hopefullly the sensors will still work as they should in the new locations.

 

I want to do that also to the Legato, but I want SOME protection left for knock sense. Engine damaging detonation is not necessarily audible to the human ear.

 

I don't want to alway run premium either, as this seems to help.

 

Aside from an audio knock sensor, it seems there would be someway to monitor detonation through gas analysis or a noise filter or something something, but I haven't found one.

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I did this to my mom's 98 outback which has severe piston slap on cyl 4, right under the knock sensor. It helped a lot, but when I pulled a knock sensor off of another block I had and put it on hers in the origional location, it worked properly. No code, better millage, and none of the pulling timing BS it was doing with the old knock sensor. So piston slap doesn't set off the knock sensor unless the sensor is BAD. If you need to relocate it, it's because the sensor is bad. Use relocation only as a method to get by untill you replace the sensor with a new one. Without the sensor located on the block in the proper place, you have NO KNOCK PROTECTION so run at least 89 octane and don't haul trailers.

 

I could hear the engine audibly detonating at 1/2 throttle on an uphill with an empty U-haul trailer behind it with the relocated knock sensor. Replaced it with a good sensor, no more detonation even at full throttle. Threw in a bottle of octane boost just to be safe.

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