Knock Knock

I was replacing this today. It's a knock sensor. I was getting a CEL (Check Engine Light) on it repeatedly. I thought it was getting triggered by the misfiring of the CYL 4 problem. But the sensor was defective. That's what the code actually meant.

I didn't think it was necessary to correct it since the sensor is malfunctioning. But the problem is that when the knock sensor is working and it detects 'knock', which is a combustion phase problem. It will alter the timing of the engine to correct the 'knock'. So you can't just leave it. The emissions will be impacted and fuel consumption possibly.

So 1 bolt to undo and a harness to disconnect and I'm done. 10 minute job. For a part that costs about $200.00 incl tax.

Guess where this thing goes. This is a photo of part of the engine bay.
I put a circle and highlighted where this bolts on to the engine.

I had to disconnect the battery terminal, then remove the mass air box and the operator cylinder part (that you can't see) so I could even get to the damn bolt that holds this thing to the engine block. And I had to use a flexible attachment for my ratchet to still get to it. Without it. It's next to impossible to get out.

That circle in the above picture highlights where I stuck the camera and took this next picture of where if you look closely you will see the bolt that fastens this sensor to the block. It's right in the middle of the pic, partially hidden by the wire. But you can clearly see the bolt head. It's 10mm bolt. I could barely get a snip to cut the tie that held the wires so I could get it out. But I got it out. That was the easy part. Mounting the new one was the fun part. I could barely get my hand down far enough to get 2 fingers to reinstall the damn thing. And getting the bolt on without dropping it was tricky and frustrating. I took one of Kieran's earth magnets and taped it to an old bike cable housing and used that to guide the bolt into position. I did it on the first try. After I tried and failed on a previous attempt with just my fingers. I had to think of a better way. That home made magnetic picker upper did the trick.

I'm sure this service at the dealer, just for labour would be about $200.00-300.00. At least. Just from reading what it says to do in the service manual and then actually doing it. Then the part is another $200.00. I got the actual Subaru part. I had read that after-market ones don't always work 100%. And with the aftermarket part costing almost the same. I went with the dealer.

I used the following link as reference, but this guy's car seemed to be way more accessible than mine was.

DIY link to replacing the knock sensor on a Subaru

But I did it. The car is running great. Almost like original. Only thing left for me to do is tighten the heat shield on the engine manifold cuz it's rattling a bit. That should be easy as pie, compared to this stuff.