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Thread: OMG! Knock sensor replacement is annoying me!

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Posts: 1-10 of 42
2011-01-06 03:47:46
OMG! Knock sensor replacement is annoying me!
Long story short I spent an hour WITH my car on a lift and still couldn't get the damn sensor out. I guess that's what happens on a 10 year old car that spends it's time in the North East? ARGHH. I can get a wrench on the bolt but I have zero leverage. I even tried Vadim's method of using the washer on my palm but no dice.

Anyone have any tricks or special tools needed to get this damn thing out? The only other time I replaced a knock sensor on a sr20 motor we had the starter out so it was a lot easier. I'm trying everything to avoid having to take the starter out because I don't know 100% if my knock sensor is bad or if my CEL for it is caused by something else.

pics courtesy of Vadim for reference

2011-01-06 04:39:33
This how I got my out 12 mm box wrench.you don't need to take things out jack the car up and Soak that bolt in. Wd40.then break it the next day.takes a while but no other way unless u wants to remove the I m
2011-01-06 04:45:50
I played with mine for several hours a few years back. Between the firewall, the starter and the intake manifold it's a b!tch. What's funny is looking in the FSM and seeing that the torque value is only 8 or 12 ft-lbs or something. I've broken several loose from engines that were out of the car (so it was easy to get to) and there's no WAY they were only 8-12! Had to be much more.
2011-01-06 05:49:44
I've never removed the Intake manifold but that seems like more work than pulling the starter out lol.

Is there anywhere else on the motor I can relocate the knock sensor to after I pull it out? I know a lot of 300zx guys relocate theirs but I haven't seen too much info for Sentras.
2011-01-06 05:58:29
The easy way I found is to have a GOOD ratcheting wrench. Having the right tools makes any job easier! Maybe you just need a longer wrench... but I love ratcheting wrenches haha
2011-01-06 07:05:36
Wrench Tips #7 - The Box-End Breaker Bar. try this
2011-01-06 09:31:42
find a shop with a pneumatic wrench...

2011-01-06 11:23:25
Yeah, hit it with liquid wrench or wd40 and just let it sit and pentetrate, find someone with some ass behind em and give it hell, try from the bottom.
2011-01-06 11:38:44

You need "small hands" . What year is your car? On my B14 I had to loose that metal support for the intake to get some space to work around. After I did that, I placed a wrench exactly like the picture shows plus another open wrench at the botton of the first wrench to get it loose. Like this:

Is kind of difficult and you need to be patient but it can be done.
2011-01-06 11:40:40
Originally Posted by JakeB
find a shop with a pneumatic wrench...

There is not enough space between the sensor and that metal tube showed in the picture to use that kind of wrench. You need to use an open wrench like the picture shows.
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