legacycentral bbs

So me being a bit of a gear head and also a Subaru noob, I've been poking my head around under the hood getting a good feel for what is where.

My first inspections of the electricals have come up with some needed repairs. I found a sensor that's located in the front of the engine on the right side by the battery, it's bolts into the back side of the timing belt cover, what sensor is this? Mine was loose and I pulled it out and wiped it off and put it in right.

The knock sensor plug, the harness end of it is missing the outer sheath of the wire about 1-2 inches back from the plug and the wire that is between the inner core and the outer sheath is not going to the plug. Is there 1 wire or 2 that goes to the knock sensor? Shouldn't that throw a knock sensor code if the wire was broken? There's no CEL light on and I know it works it flashes at start up.

There's a ground wire, it think it's the transmission ground, in the middle by the fire wall that goes down to the tranny, mines a manual. On the tranny end the ring connector has been broke off and the rest of it was jammed under a clip like thing on the top of the trans casing. Where does the trans end bolt to?

Pics would be wonderful but I would appreciate any advice you have.

The sensor you're describing is the cam sensor.
The knock sensor has one wire and it only pulls timing. Having it disconnected won't hurt anything.
I can't tell you where the ground wire goes, but Josh (Legacy777) has FSM scans on his website that'll have the info you need.

If the knock sensor only has one wire why would the factory end have 2 wires inside? I don't mean the plug has 2 terminals inside, I haven't looked inside the connection to find out yet.

The 'other' wire is the end of the shielding that surrounds the signal wire. Its best that it be grounded, but not completely necessary.

Looks like I need to search for the harness end of the knock sensor connector. Upon closer inspection the end the harness wire goes into is very beat up, it appears that someone before me had a hard time unhooking the sensor. Lots of gouges in the plastic.

How far back into the wiring harness should I go for a good splice? Should I go back to where they spliced it? What year range would I be able to get this from? I know of a 1995 outback in a nearby salvage yard, the engine is pulled tho and when I went into it I wasn't looking in that area at all so I have no clue if its still attached and wasn't just hacked off.

I am really starting to enjoy driving my Legacy and I'm also enjoying all the fixes it needs. The to do list is pretty long but the car's in good enough shape that I'm willing to do it.

What color connector is your knock sensor? There was an older design with a gray connector that is known to crack and cause issues. The newer style sensor has a white connector. I'd suggest replacing the older one with a new style if you still have the older sensor. As for the wiring, there is only one wire, and it's shielded. From my experience the knock sensor wire is rather brittle and honestly, you're better off trying to replace it. You can use microphone wire as it's shielded and run it from the knock sensor to the ECU. If you want to try and splice into the existing wire make sure you use a multi meter to check for resistance from the ECU connector to the wire in the engine bay. With a set of small jewlers screwdrivers you can remove the plastic connector, cut the wire going to the connector and then solder the new wire to the connector and put the plastic connector piece back on.

There are a couple pics of my repair here.

http://www.main.experiencetherave.com/s ... install/06

Also, sometimes the ECU won't display a code for the knock sensor....I'm not sure why, but it doesn't. It appears to be an issue with the turbo Legacy ECU's. I'm not sure how long my knock sensor wiring was bad, I just happened to find it when I did my stand alone install and did all my wiring checks.

As for the trans ground wire, just put a new ring terminal on and connect it anywhere on the transmission.

I'm going to have to pick up a new plug. This one is just too jacked up. The plug is white on my car.

I feel there is a possibility that it has been changed when the motor was replaced.

Legacy777 wrote:What color connector is your knock sensor? There was an older design with a gray connector that is known to crack and cause issues. The newer style sensor has a white connector. I'd suggest replacing the older one with a new style if you still have the older sensor. As for the wiring, there is only one wire, and it's shielded. From my experience the knock sensor wire is rather brittle and honestly, you're better off trying to replace it. You can use microphone wire as it's shielded and run it from the knock sensor to the ECU. If you want to try and splice into the existing wire make sure you use a multi meter to check for resistance from the ECU connector to the wire in the engine bay. With a set of small jewlers screwdrivers you can remove the plastic connector, cut the wire going to the connector and then solder the new wire to the connector and put the plastic connector piece back on.

There are a couple pics of my repair here.

http://www.main.experiencetherave.com/s ... install/06

Also, sometimes the ECU won't display a code for the knock sensor....I'm not sure why, but it doesn't. It appears to be an issue with the turbo Legacy ECU's. I'm not sure how long my knock sensor wiring was bad, I just happened to find it when I did my stand alone install and did all my wiring checks.

How long of a wire did you need for that replacement?
What gauge wire did you use?
Could I get away with patching the replacement plug into the factory wire if I make sure to have enough of the shielding wire to overlap? I have a new plug with about a foot tail on it.
That wire needs to be shielded, how much shielding does it need? From your pictures you used some extra wire to make a homemade shielding, did you have to cover every inch of the inside wire or are gaps ok to have?

My idea is to cut off the harness end up to where the covering is stripped off, remove enough covering to have about an inch overlap for shielding and use shrink tubing to cover the inside wire after soldering it.
Am I wasting my time with this idea?

The shielding isn't entirely essential. From my understanding, its there mostly to keep out other electrical signals so as not to corrupt the actual signal to the ECU. I'm sure a short gap in the shielding won't affect the performance of the sensor, but your idea sounds like a good fail-safe.

The wire I used was shielded and a brand new wire from my stand alone ECU. I didn't use the old wire.

An 18 gauge wire should be fine.

You should be ok with what you're proposing. When you're finished, just check continuity from the sensor plug to the ECU to ensure it's 0 ohms.