Toyota 3.4L 5VZ-FE Knock Sensor location

[EatonKyleH]

Yeah, thats what I figured. I've got 260+ thousand miles but the engine is newish at 30,000 miles. I've put this off because my inspection doesnt expire until November...and I just replaced my engine coolant Mo Money!!!

When I change them, what are the benefits beside turning the CEL light off? I'm hoping to get better gas mileage...

I bought my 4runner needing this same repair (previous owner traded it because of it) and I've done it on customers vehicles many times. Most vehicles with knock sensor codes are unaffected performance wise under normal conditions but on these 4Runners the ECM actually retards the timing to potentially protect itself from knock if it were to occur while the sensor was reported to the ECM as faulty (make sense?).

The performance and MPG gains after repairing this issue are actually pretty darn significant on this model. You'll be glad you did it.

 

[rideexileex]

Good luck! I just recently did this... took me a night after work to get it apart, and a night to get it all put back together. The real fun starts once you get the upper intake manifold off. The lower manifold, rear bolts are not easy to get to.

 

[Sandspur]

Thanks guys all good info, The end of the wiring harness where it connects on the passenger side is in good shape. I thoght may be there would be a bypass for now untill I find time . Any suggestions?

 

[EatonKyleH]

Thanks guys all good info, The end of the wiring harness where it connects on the passenger side is in good shape. I thoght may be there would be a bypass for now untill I find time . Any suggestions?

Typically its the wiring in the harness itself (under the intake due to heat) that fails not the connectors. There is not really a temporary fix in most cases.

 

[MojaveMadMan]

I posted about mine, but I think it got deleted with the site crash. I replaced the wire, buttoned it up and the light came back on after about 40 miles... Had to re-accomplish and actually replace the sensor on a 2nd tear down... things are looking better, I think I fixed it now. I will say the sensor did bench test as good, but ultimatelty was bad, something to think about if you have it all appart and don't want to do the job twice like I did... Though I am an intake removal pro now!

 

[TXRick]

Finally going to get this one done. I found nippondenso and matsushita knock sensors on Rock Auto for $105 each. They seem to be the same as the ones direct from the Toyota stealership. Any opinions on nippondenso vs matsushita?

I also found this site which was helpful

Toyota Knock Sensor | MDH MOTORS

 

[nor_cal51501]

Finally going to get this one done. I found nippondenso and matsushita knock sensors on Rock Auto for $105 each. They seem to be the same as the ones direct from the Toyota stealership. Any opinions on nippondenso vs matsushita?

I also found this site which was helpful

Toyota Knock Sensor | MDH MOTORS

Factory I had the matsushitas and I replaced them with the Densos and haven't had any issues. Also, the Densos are usually factory stocked and the matsushitas are normally s/o so take a little longer.(Rockauto may have in stock, idk) the dealer told me that they usually replace the matsushitas with the Densos because of availability of the matsushitas. They look slightly different but both perform same and are both equally reliable.(per local toyota tech) I've had no issues since installing mine and highly doubt that I will have any issues.

Edit: [MENTION=88740]TXRick[/MENTION], just in case you weren't going to, make sure you replace the harness pigtail also, it's actually usually the pigtail that goes bad, not the sensors. I did both as preventative maintenance(didn't want to pull the intake manifold again just in case).

 

[TXRick]

Factory I had the matsushitas and I replaced them with the Densos and haven't had any issues. Also, the Densos are usually factory stocked and the matsushitas are normally s/o so take a little longer.(Rockauto may have in stock, idk) the dealer told me that they usually replace the matsushitas with the Densos because of availability of the matsushitas. They look slightly different but both perform same and are both equally reliable.(per local toyota tech) I've had no issues since installing mine and highly doubt that I will have any issues.

Edit: [MENTION=88740]TXRick[/MENTION], just in case you weren't going to, make sure you replace the harness pigtail also, it's actually usually the pigtail that goes bad, not the sensors. I did both as preventative maintenance(didn't want to pull the intake manifold again just in case).

Yeah, I've got the wiring harness on order. I tried to order the knock sensors today but something is wrong with my card...so I think I will go with my original plan and order the harness and install that so I dont waste and cash...'

thanks!

 

[nor_cal51501]

Yeah, I've got the wiring harness on order. I tried to order the knock sensors today but something is wrong with my card...so I think I will go with my original plan and order the harness and install that so I dont waste and cash...'

thanks!

Also, since you are going to do just the harness you can test the knock sensors while your that far into the intake. All you have to do is ohm test them while tapping the end on a solid surface(a table is best NOT the ground). Then you know that your knock sensors are good before re assembling the intake manifold assembly. Will save you a ton of time on assembly/disassembly on your manifold assembly if you do have a bad sensor.

 

[TXRick]

It's the wire that is to the right of the top water pump outlet

And it connects like this:

I figured this is a better post to reply to.

So, I've got it apart and replaced both sensors.

I am having trouble with the harness. It runs out the front of the engine but it's stuck and I can't pull it through. I see where it starts and ends but it's ran very tight out the front and in between the cam wheels.


Mine comes out here and is stuck. Even if I get it out how am I going to run it back through?

I'm thinking when the engine was rebuilt they didn't run the wire right. Can anyone tell me how it's supposed to be run?

 

[nor_cal51501]

I figured this is a better post to reply to.

So, I've got it apart and replaced both sensors.

I am having trouble with the harness. It runs out the front of the engine but it's stuck and I can't pull it through. I see where it starts and ends but it's ran very tight out the front and in between the cam wheels.


Mine comes out here and is stuck. Even if I get it out how am I going to run it back through?

I'm thinking when the engine was rebuilt they didn't run the wire right. Can anyone tell me how it's supposed to be run?

That's NOT the knock sensor. Your knock sensor is below the intake manifold in the motors valley. Here's mine when I did it so you have a better idea what/where you SHOULD be looking.

http://www.toyota-4runner.org/3rd-gen-t4rs/160604-nor_cal51501s-build-thread-2.html#post1644707

 

[TXRick]

That's NOT the knock sensor. Your knock sensor is below the intake manifold in the motors valley. Here's mine when I did it so you have a better idea what/where you SHOULD be looking.

http://www.toyota-4runner.org/3rd-gen-t4rs/160604-nor_cal51501s-build-thread-2.html#post1644707

Yeah, I know that's not the knock sensor. That's where the knock sensor harness wire is coming out of the valley.

Here are the knock sensors.

 

[TXRick]

That's NOT the knock sensor. Your knock sensor is below the intake manifold in the motors valley. Here's mine when I did it so you have a better idea what/where you SHOULD be looking.

http://www.toyota-4runner.org/3rd-gen-t4rs/160604-nor_cal51501s-build-thread-2.html#post1644707

I'll be more clear.
The harness wire goes from the knock sensors then trough this thin metal plate here

Then out the other side here

And ends up here on the passenger side here

Like I said before, it looks like it's routed wrong. I'd have to cut it to pull it out. How is the harness wire supposed to be run?

 

[TXRick]

It's the wire that is to the right of the top water pump outlet

And it connects like this:

Ok, after looking at this pic for the millionth time, it looks like I was right. The idiots who rebuilt this engine ran the wire wrong. It looks like I'm supposed to run it out the top.

Up all night, sleep all day!
Except I have to work tomorrow...

 

[nor_cal51501]

I'll be more clear.

The harness wire goes from the knock sensors then trough this thin metal plate here

Then out the other side here

And ends up here on the passenger side here

Like I said before, it looks like it's routed wrong. I'd have to cut it to pull it out. How is the harness wire supposed to be run?

That makes things so much easier. Glad you know the difference, I was seriously considering telling you to just take your car in and get it done. (Cause I thought you didn't know the difference between the camshaft position sensor and knock sensors) The wire harness actually just comes up and out on the right-ish side of the water return line(I believe it's the return) on the intake manifold in between the metal plate and the intake manifold. I'll snap a pic real quick and upload it in 2 seconds.

 

[nor_cal51501]

You can see the harness running along the metal plate for the timing cover backing and under the water return line.

Took this pic looking down between the timing cover and next to the drivers side fuel rail.

 

[TXRick]

Awesome! Yeah, those pic will help a lot. I'll prolly go buy all new gaskets tomorrow and button it all back up. Thanks for the help

 

[nor_cal51501]

No problem bud, good luck with the rest. Hope it all goes smoothly. Also, found this picture that shows a MUCH better view of when I pulled mine apart. This shows EXACTLY where factory routing is. Hope this helps out [MENTION=88740]TXRick[/MENTION]

 

[Greg_Canada]

Looks like you guys figured it out! there is a little chamfer in the intake manifold which makes space for the wire to squeeze through.

Good luck!

 

[TXRick]

Yeah, I got it all apart and back together but I must not of seated an injector correctly because now there's a hissing sound and the smell of gas...damn 420 holiday