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Discussion Starter #1 (Edited)
So I scanned the FJ and it gave me P0333 and C1201 codes. After some research I decided to go looking for the easiest fix first, a wiring issue. Since I am the 3rd owner of this FJ I have no idea what its living environment has been and if it was accessible to all the little critters that like to eat wires. Here is a pic of the scan.
 

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Discussion Starter #2 (Edited)
I got the FJ up in the air and looked at all the wiring underneath that went to the O2 and air/fuel sensors. They all looked fine, I disconnected and reconnected each wiring clip to make sure they had a good solid connection. No issues there, so I started looking around the engine compartment and everything was good there also. The only place I could not see was under the intake were the wiring went to the knock sensors. So I got out my handy little Milwaukee camera tool and took a look up under there and saw that one of the wires going to the knock sensor had been chewed in half! So you know what is next!:frown Tear the top of the engine off.
 

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Discussion Starter #3 (Edited)
First I drained the coolant from the radiator because you will be disconnecting some coolant lines and you don't want that all over the floor. Just put a 5 gallon bucket under the radiator drain on the lower drivers side and let it drain. Then I disconnected the air filter box and moved it to the side. Then I took the rest of the intake that is before the throttle body off, two 10mm bolts, a vacuum hose in the back and loosening the clamp around the throttle body get this off. Next I took the plastic intake with the throttle body off. You need to take out all the bracket bolts, unclip all the wires and coolant hoses in the back and unbolt the intake from the plenum, then it pulls right off.
 

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Discussion Starter #4 (Edited)
Now I needed to disconnect all the injector harnesses and then disconnect the fuel line. Take the keeper blocks off the fuel line connector and then squeeze the top and bottom of the line at the connectors where they are green and yellow and pull the fuel lines apart. Next step is to take off the intake plenum. This is accomplished with a 12mm socket. Take out all the bolts holding the plenum to the heads. You will see 4 round head security type torx head bolts, leave them in, they just hold the 2 plates together. Once all the bolts are out just use a prybar a gently pry up on the plenum and it will come right out. Once I had the intake ports opened up I put towels in each one to keep stuff from entering the cylinders.
 

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Discussion Starter #5 (Edited)
Now you can finally get a look at the knock sensors and the wiring. I used a couple hook tools to get behind the coolant pipes and disconnect the harness clip from the sensor and then pulled it up above the pipes so I could get a good look at it. To get to this point took about an hour.
 

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Wow that's a hell of a lot of work for that wire. You sure there isn`t a little spot you could get to it from the underside :)
 

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"You sure there isn`t a little spot you could get to it from the underside?"


on a V engine the knock sensors are awfully hard to get to, since they need to be as close to the combustion chamber as possible (near the joint between the head and the block), which is always buried deep in the V below everything else which is located in there too

BlueBeard, well done on deciphering the cause of your issue, and of getting to that broken wire.

If I recall correctly, Toyota sells the sub harness for repair of that section so that you can splice in a new connector all pre-made.


Norm
 

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Discussion Starter #9
I ordered a new harness from Toyota today, my cost was $24.00. I will just install the whole new one and not have to worry about my splice. I will however continuity test the new harness before I install it, it would be my luck to get the one that made it through quality control with a broken wire or something!
 

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Discussion Starter #10 (Edited)
Today I ordered a new knock sensor harness, full intake gasket set, throttle body gasket and new fuel injectors. In preparation for the reassembly I cleaned the throttle body and MAF sensor, they really needed it. I also cleaned the intake plenum inside and out. Then I prepped all the metal gasket surfaces by sanding and cleaning them so they have a nice clean and flat surface as to avoid any vacuum leaks.
 

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Discussion Starter #11
I got all the parts in today, put it all back together and everything works again! No codes, more power and overdrive is working!
 

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I just did this. It was hard. I got the front and rear pipe housings off but pulling the big pipe out of the rear housing was crazy hard. I slid an old chainsaw bar between the pipes and levered against the front welded bracket that connects the big and little pipes and it popped out. I had to space the rear housing away from the head a little because that lower pipe was rubbing on the flange of the housing and I didn't want to pop a hole in it. Once the pipes were free of the housings I got tired of trying to play surgery with the wire connectors so I cut the connector pipe brackets and it allowed easy access to the sensors. It seems the big pipe kind of supports the little pipe so I just wrapped a hose clamp around the pipes and it seems good.
Here's a pic of the saw bar puller and a pic with the cuts and large pipe removed.
 

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