Looking for TRD SC pulley larger than 2.37" stock
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chris360hawks
New member
The harness has a black protective layer around the 3 individual wires. I just sliced the black layer open to reveal the gray, brown, and black wires. Don't worry you aren't going to break it. The only part that has slack in it is that piece of the harness behind the timing cover. That part isn't brittle so don't worry. I just went to my toyota dealership and had the parts guy pull up the schematic for the harness. It should which individual wire went where. I actually purchased a extra harness that way I could visualize it better when I was performing the splice. It is really simple it took me all of maybe 10 minutes to complete.
nacho
New member
Hmmm.... If there are only 3 individual wires.. a brown, a gray and a black, with the black being the ground wire...then it would seem that the only thing to splice together would be the brown wire to the gray wire.
That would mean stripping some insulation off of the brown wire and the gray wire and connecting the two together.....correct? Just leave the black ground wire alone?
I really appreciate all the help you've given me (and hopefully others) with this procedure. Thanks.
That would mean stripping some insulation off of the brown wire and the gray wire and connecting the two together.....correct? Just leave the black ground wire alone?
I really appreciate all the help you've given me (and hopefully others) with this procedure. Thanks.
chris360hawks
New member
Yes you will be splicing the two wires together but you have to make sure you cut power to the correct sensor. You don't want to cut the power to the "good" sensor and then have the signal from the bad sensor supplying the signal for both wires. That will really screw everything up. You want to cut the power to the bad sensor and then take the end of the wire that goes into the connector and splice that into the power for the good sensor. Does that make sense? That way one sensor will be supplying a good signal for both connections.
nacho
New member
Thanks, that makes perfect sense now. I want to leave the good wire intact, cut the wire that comes from the bad sensor and splice the end that goes back to the ECU into the good wire and just tape off the other end that goes back to the bad sensor. So basically there is still 2 wires coming from the ECU until they come together at the splice and then just 1 wire goes to the 1 good sensor. The ECU is getting it's 2 readings from just the 1 good sensor. I have noticed that they do this same trick on other forums where the vehicles have 2 sensors and only one goes bad.
I did find the harness wire right exactly where you said it would be. There was a white connector on the left side and there was about 4 inches of the harness on the right. I pulled back the black sheathing that protects the wires at the connector so I could see the wires. Guess what? There was only 2 wires in mine. One was brown and the other was green with a yellow stripe on the side of it. No other wires were in there....so I guess my set-up is a little bit different than yours.
All I have to do now is figure out which wire goes to the bad sensor... (#2) and which one goes to the good sensor ...(#1).
Once I figure that out it should be an easy thing to do the splice. There isn't a whole lot of room to do the splicing, but just enough it looks like.
Thanks Chris360Hawks for getting me this far. Couldn't have done it w/o your input.
BigFishAllDay has also been a great help with everything. Thanks dude.
One thing that kind of bothers me is that these knock sensors seem to go out all the time...and the harness wires going to them also fail.
9 times out of 10 when you get a CEL knock code on any vehicle, it's usually either one of the knock sensors or the wiring harness that goes to them has gone bad. Even if you get a CEL KS code because you are actually vibrating enough to trip one of the KS, there is no way to tell what the exact cause is that tripped the KS to throw a code.
I can now see why so many people just do "the splice" and wait until the other KS goes out. What's the point in spending all that money to only replace 1 sensor?
I did find the harness wire right exactly where you said it would be. There was a white connector on the left side and there was about 4 inches of the harness on the right. I pulled back the black sheathing that protects the wires at the connector so I could see the wires. Guess what? There was only 2 wires in mine. One was brown and the other was green with a yellow stripe on the side of it. No other wires were in there....so I guess my set-up is a little bit different than yours.
All I have to do now is figure out which wire goes to the bad sensor... (#2) and which one goes to the good sensor ...(#1).
Once I figure that out it should be an easy thing to do the splice. There isn't a whole lot of room to do the splicing, but just enough it looks like.
Thanks Chris360Hawks for getting me this far. Couldn't have done it w/o your input.
BigFishAllDay has also been a great help with everything. Thanks dude.
One thing that kind of bothers me is that these knock sensors seem to go out all the time...and the harness wires going to them also fail.
9 times out of 10 when you get a CEL knock code on any vehicle, it's usually either one of the knock sensors or the wiring harness that goes to them has gone bad. Even if you get a CEL KS code because you are actually vibrating enough to trip one of the KS, there is no way to tell what the exact cause is that tripped the KS to throw a code.
I can now see why so many people just do "the splice" and wait until the other KS goes out. What's the point in spending all that money to only replace 1 sensor?
chris360hawks
New member
Yes that is exactly what you are supposed to do. Maybe try and look at the wires closer to the connector. I think the wires may run together in the green/yellow part. Very close to the connector you should be able to visibly see all 3 separate wires: black, grey, brown.
BigFishAllDay
New member
Just another thought too... you might have the wrong harness.
I was looking at a wiring diagram before I came to work, specifically looking for sensors in that area that have a yellow/green and a brown wire combo coming off the sensor, and the engine coolant temp sensor is wired with Yellow/Green and Brown/Black... The Knock sensors were labeled as being wired with gray, brown, and black as Chris mentioned. Take a second look at that brown wire with a flashlight and see if it's brown/black.
Just make sure you've got the right one Nacho, I'm sure we'd all hate to see you cut into the wrong wiring and run into more trouble.
I'll take a closer look at the wiring diagram tomm and see if the gray, black, brown merge into a yellow/green at some point and reply back.
I was looking at a wiring diagram before I came to work, specifically looking for sensors in that area that have a yellow/green and a brown wire combo coming off the sensor, and the engine coolant temp sensor is wired with Yellow/Green and Brown/Black... The Knock sensors were labeled as being wired with gray, brown, and black as Chris mentioned. Take a second look at that brown wire with a flashlight and see if it's brown/black.
Just make sure you've got the right one Nacho, I'm sure we'd all hate to see you cut into the wrong wiring and run into more trouble.
I'll take a closer look at the wiring diagram tomm and see if the gray, black, brown merge into a yellow/green at some point and reply back.
chris360hawks
New member
I was looking at my new harness and I think the wires do merge together, thats why he needs to move closer to the connection to see them all individually.
BigFishAllDay
New member
Just took a look at the wiring diagram.... I followed the wires off the knocks sensors all the way back to the ECU and sure enough, they are not shown to merge. Black and Grey go into the ECU as black and grey, and brown goes to ground.
nacho
New member
Now I'm really baffled. That wire harness is exactly where C360H said it should be. There is a white connector on the left side and the harness goes down behind the timing belt cover. I un-clipped the white connector and looked into it. There are only 2 terminals in each side and there are only 2 wires coming out of it on either side. One is brown and one is green with a yellow stripe on the side of it. There definitely is no third wire.
I sprayed a little silicone into the connector and clipped it back together.
I cannot see any other wiring harness in that area that resembles what we are talking about. I took a flashlight and inspected that whole area.
This is a 2000 4wd SR5 3.4 auto, so I doubt that it has a different wiring set-up than the 4R's you both have.
Maybe the only choice I have now is to take out the glove box to access the ECU and see if I can locate the Black and Grey wires.
I still need to find out which sensor the Black wire goes to and which sensor the Grey wire goes to.
I find it strange that Toyota would use a Brown wire for the ground in this set-up. Normally, Black is what is used for a ground wire.
I'll go out again and do another inspection and see if I missed something. I know what I'm looking for....it just doesn't seem to be located where I think it should be. Maybe they routed my 2000 in a different way?
Thanks guys for hanging in there with me so far. This must be getting old by now. Thanks for the tenacity.
I sprayed a little silicone into the connector and clipped it back together.
I cannot see any other wiring harness in that area that resembles what we are talking about. I took a flashlight and inspected that whole area.
This is a 2000 4wd SR5 3.4 auto, so I doubt that it has a different wiring set-up than the 4R's you both have.
Maybe the only choice I have now is to take out the glove box to access the ECU and see if I can locate the Black and Grey wires.
I still need to find out which sensor the Black wire goes to and which sensor the Grey wire goes to.
I find it strange that Toyota would use a Brown wire for the ground in this set-up. Normally, Black is what is used for a ground wire.
I'll go out again and do another inspection and see if I missed something. I know what I'm looking for....it just doesn't seem to be located where I think it should be. Maybe they routed my 2000 in a different way?
Thanks guys for hanging in there with me so far. This must be getting old by now. Thanks for the tenacity.
chris360hawks
New member
I think the black wire is the ground. I will look at my truck on Monday when I see it again and check what harnesses are behind my timing cover. If I remember correctly mine may have had two different harnesses in it.
BigFishAllDay
New member
I'll take a picture of the wiring diagram tomorrow and post it here for you, so that you both can see for yourselves. Done deal. The wiring diagram is for the 2000 model year, so it will be dead on for what you should be seeing in your truck Nacho.
Also, it identifies which wire is connected to which sensor, ie, whether black/grey goes to knock sensor 1, or 2... so you can identify which wire will need to be moved around.
Also, it identifies which wire is connected to which sensor, ie, whether black/grey goes to knock sensor 1, or 2... so you can identify which wire will need to be moved around.
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nacho
New member
Thanks C360H....I would appreciate that.
I think that BigFishAllDay may be right about that harness that only has a brown wire and a green/yellow wire in it. It looks like it goes down to a heat sensor unit from the left side of the white connector.
Both of you are saying there are 3 wires: Black-Brown-Grey. I believe both of you are correct. Those are the wires I need to locate. There is
no way my 4R can be that much different than yours. We both have the grey SC also.
If I cannot locate them in my engine compartment I guess I will have to take out the glove box and try to find those wires where they go into the ECU. Does that sound feasible?
I would much rather do it from the engine compartment like you did. It
would be better in the long run if I need to re-wire it back in the future when I have to replace both sensors.
I think that BigFishAllDay may be right about that harness that only has a brown wire and a green/yellow wire in it. It looks like it goes down to a heat sensor unit from the left side of the white connector.
Both of you are saying there are 3 wires: Black-Brown-Grey. I believe both of you are correct. Those are the wires I need to locate. There is
no way my 4R can be that much different than yours. We both have the grey SC also.
If I cannot locate them in my engine compartment I guess I will have to take out the glove box and try to find those wires where they go into the ECU. Does that sound feasible?
I would much rather do it from the engine compartment like you did. It
would be better in the long run if I need to re-wire it back in the future when I have to replace both sensors.
BigFishAllDay
New member
Nacho,
As promised, I have posted the wiring diagram below. This diagram is from a Haynes Repair Manual for 1996-2000 model year Tacomas, T-100's, and 4-Runners. The diagrams below are for a TACOMA 3.4l V-6, but they should be identical to the wiring on the 4-Runner's 3.4l V-6. Per the FSM link I posted earlier, (http://www.ncttora.com/fsm/1996/SIL...2rmsour/2002/024runne/di/eg5vzfe/cip0325p.pdf) code P0330 indicates a "Knock Sensor 2 Circuit Malfunction (Bank 2)". This is the sensor on the left bank... the wire going to this sensor should be GREY. (BTW, also note the BROWN wire going to ground.)
Assuming this is your bad sensor, in order to do the splice and send the GOOD signal from Knock Sensor 1 (Bank 1, on the right hand side) to both of the Knock Sensor signal input terminals on the ECU, you would have to cut the GREY wire, either at the ECU, or at the harness. You would then take the end of the GREY wire that goes INTO THE ECU and splice it into the BLACK wire. Do not cut the black wire, just strip off some insulation, tap the GREY wire into the BLACK wire, solder it, and cover the splice with some electrical tape.
The end of the GREY wire going into Knock Sensor 2 (Bank 2, left hand side), would simply need to be taped off. It will no longer be connected to anything but the knock sensor itself.
And here's a shot of the wiring diagram that shows the wiring coming off the Engine Coolant Temperature Sensor, the green/yellow and brown/black. This is what led me to believe you may be looking at the wrong harness.
As promised, I have posted the wiring diagram below. This diagram is from a Haynes Repair Manual for 1996-2000 model year Tacomas, T-100's, and 4-Runners. The diagrams below are for a TACOMA 3.4l V-6, but they should be identical to the wiring on the 4-Runner's 3.4l V-6. Per the FSM link I posted earlier, (http://www.ncttora.com/fsm/1996/SIL...2rmsour/2002/024runne/di/eg5vzfe/cip0325p.pdf) code P0330 indicates a "Knock Sensor 2 Circuit Malfunction (Bank 2)". This is the sensor on the left bank... the wire going to this sensor should be GREY. (BTW, also note the BROWN wire going to ground.)
Assuming this is your bad sensor, in order to do the splice and send the GOOD signal from Knock Sensor 1 (Bank 1, on the right hand side) to both of the Knock Sensor signal input terminals on the ECU, you would have to cut the GREY wire, either at the ECU, or at the harness. You would then take the end of the GREY wire that goes INTO THE ECU and splice it into the BLACK wire. Do not cut the black wire, just strip off some insulation, tap the GREY wire into the BLACK wire, solder it, and cover the splice with some electrical tape.
The end of the GREY wire going into Knock Sensor 2 (Bank 2, left hand side), would simply need to be taped off. It will no longer be connected to anything but the knock sensor itself.
And here's a shot of the wiring diagram that shows the wiring coming off the Engine Coolant Temperature Sensor, the green/yellow and brown/black. This is what led me to believe you may be looking at the wrong harness.
nacho
New member
Good man there BigFishAllDay!!! Thank you very much for posting this for me/us. You were correct that the brown is indeed the ground. It really helps to clear up what color wire goes to what sensor. Perfect!
The pic is very readable except for the 3 numbers or letters right in front of the 1 and 2 at the ECU where the black and grey wires go. I can't quite make out what those letters/numbers are. I tried enlarging the picture, but it just made things more blurry.
Would you mind looking at it and telling me what they are? It looks like I will have to be going in from behind the glove box and do the splice right at the ECU. Your directions for doing the splice are right on. Thanks.
Just as a note...I bought a Haynes FSM when I first got the 4R, but it covers tacos, 4R's and T-100's from 93 - 2004, so they spread their info pretty thin. I need to get a better FSM that narrows it down more.
Thanks for being a great help to me and hopefully many others that will encounter this issue. Good man!
I'll let you know how this splice test turns out.
Just out of curiosity, what gap do you use on your 2 step colder spark plugs? I set mine at .043 as suggested by the manua
The pic is very readable except for the 3 numbers or letters right in front of the 1 and 2 at the ECU where the black and grey wires go. I can't quite make out what those letters/numbers are. I tried enlarging the picture, but it just made things more blurry.
Would you mind looking at it and telling me what they are? It looks like I will have to be going in from behind the glove box and do the splice right at the ECU. Your directions for doing the splice are right on. Thanks.
Just as a note...I bought a Haynes FSM when I first got the 4R, but it covers tacos, 4R's and T-100's from 93 - 2004, so they spread their info pretty thin. I need to get a better FSM that narrows it down more.
Thanks for being a great help to me and hopefully many others that will encounter this issue. Good man!
I'll let you know how this splice test turns out.
Just out of curiosity, what gap do you use on your 2 step colder spark plugs? I set mine at .043 as suggested by the manua
BigFishAllDay
New member
The part you're having trouble seeing says:
BLK
------------(l KNK1
GRY
------------(l KNK2
Re the plugs, after the research I did, the gap that I decided I'd try was 0.032. I haven't pulled the plugs since I bought the truck, but I've got a set of Denso IK22's I ordered from URD that I'm gonna throw in once I get around to installing their upgrade kit for the TRD 7th... and the wideband... and the 2.2" pulley... I still have lots of work to do.
BLK
------------(l KNK1
GRY
------------(l KNK2
Re the plugs, after the research I did, the gap that I decided I'd try was 0.032. I haven't pulled the plugs since I bought the truck, but I've got a set of Denso IK22's I ordered from URD that I'm gonna throw in once I get around to installing their upgrade kit for the TRD 7th... and the wideband... and the 2.2" pulley... I still have lots of work to do.
nacho
New member
Thanks for posting those numbers....and everything else. Great help!
Good luck with your truck mods. I hope it all goes well and gives you the performance you expect.
Funny how this thread got side tracked with the knock sensor wiring test. I'm glad it did and you guys stuck it out and didn't give up.
Curious as to what s.plug gap C360H uses on his and his 2 friends trucks.
Maybe mine are gapped to wide at .043 with the SC in the equation.
Good luck with your truck mods. I hope it all goes well and gives you the performance you expect.
Funny how this thread got side tracked with the knock sensor wiring test. I'm glad it did and you guys stuck it out and didn't give up.
Curious as to what s.plug gap C360H uses on his and his 2 friends trucks.
Maybe mine are gapped to wide at .043 with the SC in the equation.
chris360hawks
New member
I have triple prong NGKs at factory gap, I don't think you are supposed to mess with the gap on stuff that has more than two electrodes.
SkidPalace
Member
Not that it will help much, but I thought I would chime in and report that I have the 1st Gen SC and no other fuel upgrades other than the free FMU mod and I have no pinging issues to speak of.
In fact, I didn't even run premium fuel for the longest time when the price of gas started going bananas several years ago. My ECU simply adjusted to the reduced octane and decreased performance. I had a little bit of knocking going on when I drove with the cheap gas, but I learned how to drive to avoid it. It's funny, I recall that my truck would have good days and bad days where sometimes it would run a bit sluggish and other days I would be surprised with neck snapping acceleration.
Looking back, I would assume that to be dependent upon the quality of the gas that was put in at the time or due to atmospheric conditions (pressure, temp or humidity).
When I finally wised up, I realized that I got all my power back when I ran premium fuel. She runs like a champ every day now.
I also figured I would take it a step further and switched to colder plugs when it came time to do plugs and wires. I used one step colder versions of the stock Denso copper plugs, K20TR11s, with a new set of blue NGK wires. I didn't notice any change in performance or knock, since it didn't really knock to begin with.
Nacho, hopefully when you isolate that bad knock sensor your issues will disappear.
In fact, I didn't even run premium fuel for the longest time when the price of gas started going bananas several years ago. My ECU simply adjusted to the reduced octane and decreased performance. I had a little bit of knocking going on when I drove with the cheap gas, but I learned how to drive to avoid it. It's funny, I recall that my truck would have good days and bad days where sometimes it would run a bit sluggish and other days I would be surprised with neck snapping acceleration.
Looking back, I would assume that to be dependent upon the quality of the gas that was put in at the time or due to atmospheric conditions (pressure, temp or humidity).
When I finally wised up, I realized that I got all my power back when I ran premium fuel. She runs like a champ every day now.
I also figured I would take it a step further and switched to colder plugs when it came time to do plugs and wires. I used one step colder versions of the stock Denso copper plugs, K20TR11s, with a new set of blue NGK wires. I didn't notice any change in performance or knock, since it didn't really knock to begin with.
Nacho, hopefully when you isolate that bad knock sensor your issues will disappear.
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