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Got this 92 turbo about a year ago. Everything started off perfectly. After a few months a check engine light came on during a car wash? Turned off a few minutes later. Everything fine again for a few months. Started throwing a code again but usually turned itself off within a couple minutes. Transmission started to go out so I ended up taking it to a shop for a full rebuild (automatic trans) and got it back with a code for the knock sensor. Did it’s usual thing of turning off and on intermittently. Ended up taking it back to get the codes read and it threw knock sensor again, this time it also threw injector #2 and a MAF code. Couldn’t find any leaks so replaced the Maf thinking maybe just a goofy sensor. Replaced my injectors. And also replaced my knock sensor. Whoever replaced the knock sensor beforeme didn’t do the prettiest work so I ran a new wire from the knock sensor back to the area close to the turbo. Still has the knock sensor code. This dreaded check engine light has plagued my mind for over a month now. I’ve checked so many wires and I feel I just have no idea what to do next. Any advice or ideas would be amazing! This is my first Subaru so take it easy on me if this is something obvious. Still on stock ecu

I wouldn't worry about the CEL and MAF code. All mine do that when they get moisture in the intake.

There's not much to go wrong in a knock sensor other than the physical wires in the harness and the sensor itself. Have you measured resistance?

Welcome to the BBS.

These cars with the OBD1 ECU's are not the smartest so sometimes the CEL being on can actually cause a drivability issue or be more a nuisance.

Forget the CEL, how does the car drive? Do you have any drivability issues or poor engine running/performance?

You can check/clear the codes yourself using the information on my site:

https://surrealmirage.com/subaru/engine.html

I would suggest checking for stored codes with the black connectors first. Then check for "active" codes using only the green connectors. Once you've done that and recorded the information, clear the codes via the method on my site with both the green and black connectors connected. If you get a CEL again, you can go through the checking process again to verify the codes are "real" and not phantom codes from the past.

Regarding the MAF and knock sensor.....it sounds like the issue is more likely wiring than the sensors themselves. The MAF sensor utilizes a shielded wire to reduce EMF interference. The knock sensor is similar and utilizes a very low voltage. Both of these sensors wiring, especially the knock sensor are not really suitable to splice or fix. If there are splices or other modifications to the wiring the best bet would be to run a new shielded wire from the ECU to the sensor connector. Microphone wire is a good option for shielded wiring and would work for the knock sensor. For the MAF sensor, since there are several individual wires inside the shielded casing you would need to ensure you use a microphone wire with enough leads for the MAF sensor....I think you would have at least three.

You can buy copper wire mesh loom for shielding stuff.

You can also do what Ford does and just run the wire in an aluminum foil sleeve.

In both cases the shield needs to be grounded.

The shield should be grounded to the sensor ground pin/input on the ECU and no where else.