My Supra now has a constant code 52.  I wasn't sure if this was an actual bad knock sensor or wiring.  Since the wiring was the cheaper of the two repairs, I opted for it.  I read the tech tip and will definitely be shortening the connector that goes behind the starter so I won't have to remove it for any future knock sensor work.  A set of new connectors is $20.00, but I will use my old ones as I have a spare in my parts car just in case I need one.

I completely removed the hood for this as I would be working at the back of the engine compartment.  I also removed the strut and the metal vacuum line assembly that are under the intake to give myself room to get my arm in there.  I was unable to get my starter loose at the time.  I guess I shouldn't have tightened it so much during my loose manifold engine repair.  What I ended up doing was loosening the motor part of the starter to get it out of the way after taking the positive terminal off the battery.  I removed the two long bolts on the motor and gently pulled it towards the front of the car.  I made the mistake of not pressing the bearing and rotor assembly firmly into the motor housing.  If the rotor moves out about a half inch the brushes will drop off the back and are a real PITA to get back on.  There is one wire that I didn't see how to remove so I just moved the motor as far out as I could.  I also used petroleum jelly to keep the gaskets in place so they didn't drop off during reassembly.

With the starter out of the way I could remove the back connector as well.  I cut the sensor connectors off leaving myself about 4 inches of wire to work with.  I then pulled the wire and pin from connector.  I used a dremel tool to cut off the back part of one of the connectors and sanded it smooth, this will be for the back sensor.  I stripped the outer cover of the RCA cable back about 1.5 inches, used the jewelers screwdriver to pry apart a hole where the shielding crosses.  I then pushed my screwdriver into this hole, under the center conductor, and back out the same shielding hole.  This made a hump of the center conductor, and allows if to be pulled back and out leaving a good length of braided shielding to solder to.  I then stripped the center insulation back.  I soldered in the RCA cable center connector and attached about 7 inches of wire with eyelets on the end to the shields.  Scrub off any remaining flux and heat shrink everything.  The ECU end was even easier.  I removed the dash undercover, the glove box, and the panel behind the glove box.  There are 5 connectors holding the engine wiring harness to the ECU and dash wiring.  With these undone, I pulled the wiring harness out of the car.  I had to cut back the factory electrical tape to get at the wires I wanted, I just made sure I remember which wires exited where and how far back for rewrapping.  The wires are white and kind of see through and go to pins 10, the front sensor, and 11, the back one.  About 6 inches back from the connector the wires run into a brown covering.  This covering is the shield running off somewhere.  I just cut the wire about two inches out from the connector, and copied the process from the sensor end.  The total length of new cable needed to go around the intake manifold, across the back of the engine compartment, and into the car was right at 7 feet.

1- The most difficult part of this repair is removing the starter.  Even if it wasn't too tight like mine, it still is a pain to get out.

1- I still have a code 52, I guess the sensor itself is bad.

For me the payoff wasn't very good.  If it had fixed the problem, then my marks would have been much higher.