I have been looking every where for the answer but can not seemed to find what im looking for. I have a Toyota 3.4L 5VZ-FE and i know where the two sensors are located. Im trying to trace where the wire is and i can not for the life of me find any pics on line. Where does the wire exit from underneath the manifold? Does anyone know? Does anyone have any photos by chance? Thanks
Toyota 3.4L 5VZ-FE Knock Sensor location
- Thread starter Sandspur
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Greg_Canada
New member
It's the wire that is to the right of the top water pump outlet
And it connects like this:
And it connects like this:
EatonKyleH
New member
Good picture above! Here is another for your enjoyment.
If you are going in there replace the knock sensor wiring harness also as it fails more often than the sensors themselves.
If you are going in there replace the knock sensor wiring harness also as it fails more often than the sensors themselves.
Greg_Canada
New member
For sure, mine disintegrated when i unplugged it. a new one was $30 IIRC. I actually replaced the entire engine harness... so much nicer not having to worry about it for the swap.
Haha thanks, appreciate it. Just need to finish up a couple things...
the great him
Elite Member
thats gonna be a screaming mini truck man... more picks and info stat!
Greg_Canada
New member
Haha i'm shooting for 300rwhp.
You can see my build thread here: Southern Ontario Toyota Trucks ? View topic - My 89' 4runner
I'm in the middle of re-building the rear suspension ATM... fixing rust holes in the frame, stripping the underbody and rust-bulleting, installing OME suspension, new axle, elocker, gas tank, fuel and brake lines, bubuilt traction bar and t-case skid, etc. etc. Already did the front end (actually just picked up a TC idler and new pitman arm... so have to swap those) basically the only part of the truck not rebuilt is the trans / t-case. and front diff... lol.
I've been kind of stale on it because my basement flooded and we are finally finishing the cleanup from that. Should get some progress in september.
TXRick
New member
Good picture above! Here is another for your enjoyment.
If you are going in there replace the knock sensor wiring harness also as it fails more often than the sensors themselves.
I have the knock sensor CEL and was thinking about just replacing the harness. Do you have to take the intake off to replace just the harness? If so, I might as well replace both sensors and the harness if I have to take the time to take all that stuff off.
Greg_Canada
New member
Yes you have to remove the intake. The knock sensors are very expensive... i think $150-250 each (i forget exactly)... might just want to try the wire first.
EatonKyleH
New member
+1 on the post above.
You can test the knock sensors by removing them and testing the AC voltage they generate when tapping on them and comparing to specs.
and you can test resistance through the harness wires while you bend it around.
but if I were a betting man I'd guess the harness is your problem over the sensors everyday.
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MojaveMadMan
New member
Haha I have this same issue on my rig, planning on messing with it this weekend as I need a smog cert to transfer title into my name here in CA.
Anyone have any tips or tricks for getting to these sensors and wiring without getting too caried away with the intake? I am very mechanical and doing the work either way will be easy, but of course I would love to save some time!!!
Also, anyone have a part number on the harness to see if I can get one from the dealer?
Anyone have any tips or tricks for getting to these sensors and wiring without getting too caried away with the intake? I am very mechanical and doing the work either way will be easy, but of course I would love to save some time!!!
Also, anyone have a part number on the harness to see if I can get one from the dealer?
Greg_Canada
New member
Basically drain coolant from radiator, remove your intake tube, unbolt throttle body, remove hoses from upper intake manifold, remove upper manifold, then you have to remove the lower manifold. I would try to keep the fuel lines connected and move them out of the way... or else you'll get fuel everywhere. then disconnect the sensors and install the new harness... careful not to ruin the sensor but the old wire will probably fall off.
I like using my FSM.... i suggest reading one.
I like using my FSM.... i suggest reading one.
MojaveMadMan
New member
I have access to one of the databases that the shops use (I saw one of the diagrams on here from the site) so I have a pritty good step by step guide from there. But I know there are always tricks to certain jobs. I guess for this one, I just need to be commited to taking it all off. Do the gaskets for the three spots on the intake I sperate need to be replaced? Or are these safe to re-use? I am guessing so, as they should be dry, and baring any damage from me, should be good to just re-use...
Greg_Canada
New member
The lower intake gaskets have coolant and air flowing through them so they will be wet. Only the upper is dry.
They should be steel gaskets, so you should have no problem re-using them all.
They should be steel gaskets, so you should have no problem re-using them all.
MojaveMadMan
New member
Well by wet I mean they have sealant on them, which makes them not reusable at all, obviously. For the lower, it should have the ribber seal on it right? I will just have to see when I take it apart, how comfortable I am to reuse it... haha. Maybe I will see if they have them at the dealer when I go to get my new harness, if they are cheap, I'll just get them anyways.
Greg_Canada
New member
Yeah, if they are 16 years old you might as well replace them. I did not use any sealant on mine, they have a seal built in. Shouldn't be too expensive. the upper gasket should be fine though.
MojaveMadMan
New member
sweet! I'll post some pics of the job and any tips I may discover along the way. Don't have time to do a full write-up. But I will do what I can for others. Gunna get elbows deep tomorrow afternoon!
TXRick
New member
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...
Greg_Canada
New member
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
When I change them, what are the benefits beside turning the CEL light off? I'm hoping to get better gas mileage...
You should get more timing advance, which will give you better MPG and more power.
As for the coolant, just drain it into a clean container so you can re-use it.
