tomboarderns

So Ive been all over this forum trying to learn everything I can about the knock sensors since I have a code 52. I know it is probably my knock sensor wire. My questions are: if I can just check my plug for corrosion what kind of spray can I use to clean it out, or should I just use sandpaper on the connections.

If that doesnt work then I have to get to the knock sensor wire. My question is after I take off the intake manifold will I have access to the knock sensor and wire or do I have to take off more parts? If I take off the intake manifold, should I have any replacement gaskets ready to replace the old ones?

I have had alot of toyotas trucks in the past, but this is the first one that Im trying to do all the work on myself and noone to teach me.

Thanks for any help.
This site has already helped me alot in the past!

tomboarderns

Sorry I failed to mention that this is a 1992 3.0 V6

ozziesironmanoffroad

Make sure the sensor is tight. My sensor wasn't even hand tight and that was giving me the code. Good luck !!

OutlawMike

Most likely it is the pigtail that jumps from the sensor to the wiring harness.

On the 3.0, the knock sensor is buried deep, under the intake manifold. To get to it (and to get the pigtail off) you have to remove the plenum (the large part on top of the motor that the throttle body attaches to), the timing belt, the idler pulley, the fuel rails, and then the intake manifold. You will need to have an intake manifold gasket kit which includes the two lower gaskets that go to the heads and the one upper gasket between the plenum and the intake manifold. Also, since you just pulled the timing belt off, you might as well look at the belt, tensioner, water pump, and idler pulley to see if they need to be done. And, since you are in there, most likely your valve cover gaskets are leaking, so, pull those to replace the gaskets. And, since you have the valve covers off, might as well check the valve clearances and adjust the shims if necessary.

A knock sensor issue on the 3.0 can snowball in a hurry.

If you get all the way in there and replace the pigtail, but then the sensor is actually the problem, then you have to go back in. So, I replaced both when I was in there. I bought the sensor from RockAuto.com, the dealer was way too expensive and I got the same part that they sell. The pigtail comes from the dealer.

Picture of the knock sensor location, it is the little green thing next to the pipe that runs front/back, dead center between the heads:

calipatient

iTrader: (1)

so the time belt has to be taken off when the plenum is removed to even have access to the sensor? i ask because i have the same problem

OutlawMike

The plenum can be removed without touching the timing belt. But, the idler pulley, dead center between the two cam sprockets, is attached to the front of the intake manifold. You have to remove that pulley and the sheetmetal backing plate to get the intake manifold off of the motor. Too get the sheetmetal backing plate off you also have to remove the two cam sprockets.

A whole bunch of fun....

tomboarderns

Thanks guys for a quick response and excellent explination. I have to find a garage to use and Ill see if I can tackle this.

buckz6319

hope this help some and I'm no expert just like to do my own mechanic work most of the time
you have to remove several other parts just to get to the #2 idler pulley like, belts,upper water outlet tube and timing belt cover #2
to remove that #2 idler pulley when you get to that part this backing plate(these are pic of how I did it) can be removed to gain access to the (4) 12mm bolts that hold down the pulley to the manifold, you will need a wobbly 1/4" extension it works the best for the tight spaces.I didn't have to remove the cam pulleys to remove that pulley( others may have had too)
wobbly 1/4 " extension with 1/4" 12 mm 6 point socket
removing the 4 12 mm blots that hold the #4 timing belt cover on(found in the cylinder head removal and replacement section of the fsm)




new #2 idler pulley


hope this helps...I have more pics if you need

OutlawMike

On this subject, I could not find anywhere in my FSM a torque spec for the knock sensor. I hit up the master tech at the local Toyota dealership. He looked it up in their shop guide. 52 in-lbs, a low torque. If you over torque the sensor he said it will shear off internally.

OutlawMike

Good info. I was pulling the heads due to a dropped valve seat (my avatar), so just pulled the sprockets and cams and pulled that piece of sheetmetal as a unit. Good to know that they did leave an avenue for servicing that did not require removing the cam sprockets.

buckz6319

thanks....just gives another option......good luck!

wizzard0z

Hi every one just a newby
I have a 4runner 95 3vzn v6 same error code 52 just replaced the HGs radiator timing belt all pullys all gaskets, my qustion i has any one relocated the knock sensor and rewired it back up to old connector and if so did it work in the new spot, if so can you post some picks as this would be a ship load easyer then breaking down the engine again.
cheers steve

buckz6319

there is a pic if someone drilling a whole and installing a knock sensor in the engine hook. I beleive it was on the left side engine hook closet to the brake booster and then making the connection.I can't look that up right now but if you search for it you may find the pic

wizzard0z

Do you know if this worked for a long time or was it a temp fix?
thanks Steve

buckz6319

Steve
I really can't answer that question, but that person did do that conversion

I think you have nothing to loose except for the hole in the engine bracket, if it works? it is not the correct way to install the knock sensor but it will get you by until you can tear down the top end and install it correctly