havenoclu

Hey all. I have the code 52 knock sensor issue and I have done a lot of related reading around the forums and think it best that I replace the wire and sensor (I really just want to try the wire...but I get the feeling that I'd be super pissed if it turned out to be the sensor, considering the work involved). Anyways, is there a procedure in the repair manual?? I cannot seem to locate it. I know it involves removing the intake plenum/manifold etc, but wanted to read over the procedure in it's entirety before attempting.

And when I say repair manual...I'm referring to the one you can download at that link in one of the stickies, named: 1990 to 1995 Toyota 4Runner OEM Repair and Wiring Manuals

Thanks!

drmix

Heres the best section in the manual I found that I think will help you out the most. Its for removing your injectors. Just ignore anything about the injectors and you should be good.

If your going through all that trouble I would check the price of the sensor as well. I wouldnt wanna do it twice just because you thought you would save a few bucks

http://personal.utulsa.edu/~nathan-b...90injector.pdf

havenoclu

Yeh, I pretty much plan on replacing the sensor as well for peace of mind purposes. Thanks for the link, helps a lot! In addition to the sensor and wire, I guess I'll replace the PCV valve and intake plenum gasket at the same time. Anything else you can think of? I don't think the valve cover gaskets are that old...but should I replace them anyway?

drmix

If they are hard and brittle I would definitely replace them. You might be able to get by without replacing them

havenoclu

Do I really need to drain the coolant?

drmix

No you shouldnt have to. Its a pretty simple process I think the hardest part is messing with the vacuum lines. I heard that you can bypass disconnecting all the vacuum lines just by disconnecting and unbolting everything else then flipping the plenum onto the passenger fender leaving the lines still attached.

You might not even have to do that much. I believe that the knock sensor just pulls out then disconnected from the harness. Maybe you could just get the plenum propped up a few inches on the drivers side then have enough room to replace it there

havenoclu

Alright, thanks for the quick reply...I'll report back after I attempt the process this afternoon.

bugs1961

I've done this a couple of times and you'll have a mess if you don't drain the anti-freeze. You will have to remove the upper timing belt idler because it is bolted onto the intake manifold and covers two intake mounting nuts. It has a main water passage that carries coolant from the intake to the water pump. The intake has water passages in both the front and rear. You'll have a mess if you don't drain first.

The KS is screwed into the block under the intake and there is no way to get it out without removing the intake.

You really need to follow all the procedures listed in the "cylinder head removal" section of the FSM, up through removal of the intake, to do the job properly and with the fewest hassles.

Plan to replace the plenum gasket, intake gaskets, the water by-pass outlet gasket (the piece on the rear of the intake that has all the sensors).

I always replace the PCV and grommet, and the valve cover gaskets while I'm in there.

It's a big job but if you try to skip steps you'll cause yourself more problems and it'll take longer than if you just do it right.

Good luck,
Bugs

havenoclu

Thanks for the info. I got rained out today, so I'll study up and give it a whirl when weather and, once again, time permit

chuntr

I did this job a couple of months ago and did a write up: https://www.yotatech.com/forums/f128...cement-233708/

cross reference the sections in the FSM for cylinder head removal and timing belt replacement for most of the stuff you need to take off and for torque specs and stuff.

you *don't* need to take apart the injectors and fuel rails. just leave them attached to the intake manifold. you do need to drain the coolant, which is not a big deal.

in addition to the other gaskets, you are also supposed to replace the copper fuel line gaskets (basically like washers) from the fuel intake line and the crossover pipes. the old ones might be fine but they were like $2 at the dealer so I got new ones.

even if the sensor works fine, you could end up like I did where the plastic clip on it was broken so the wiring harness wouldn't stay attached, and have to buy a new one anyway.

havenoclu

I don't know how I didn't find your thread when I was searching. That's exactly what I was looking for, thanks! Going to try to tackle it this weekend.

bugs1961

This thread can help with the hoses on the passenger side:

https://www.yotatech.com/forums/f116...e-help-209069/

The first picture in post #1 has all the fittings numbered and Post #11 has all the hoses identified as to where they hook up at both ends.

havenoclu

Thanks

havenoclu

Well, I was able to replace the sensor and wire yesterday and so far, no check engine light...but I've only driven about 15-20 miles thus far.

I do have one new issue though. When I let off the gas, I get this weird noise that seems to be coming from the passenger side rear of the engine bay. It may be coming from that black canister looking think in that area that says "to tank" or something like that.

The only way I can describe the noise is like someone drinking the tail end of a slurpee through a straw. Definitely sounds like a deep gurgly sucking noise. Any ideas on that?

And here's one more issue that's off topic and was happening prior to this job. I'm getting an almost metallic sound coming from somewhere on the bottom side of the engine. I can hear it best coming from the passenger side wheel well. Just soiunds like metal vibrating against metal...it's not constant, but pretty often when idling. Any ideas here as well?

Thanks for all of the help! The info/documentation was essential to me getting this done...and it pretty much couldn't have gone any smoother...aside from this one hiccup. I couldn't have done it without you guys!

havenoclu

...actually the slurping noise kinda sounds like it's coming from the intake manifold area. Really hard to tell for sure due to the sound bouncing around the engine bay. I'll try to take a vid with my phone later.

I did put the runner up on ramps and took the top off the radiator with heat on full blast in case there was air in the coolant. Maybe I didn't let it run long enough..

Think it's ok to continue driving? Seems to be driving fine..

havenoclu

Here is a video:

[YOUTUBE]http://www.youtube.com/watch?v=22cxQdHZgDU[/YOUTUBE]

BillaBongo

That sounds like the pair valve leaking, on the back of the passenger side
head.

Its the one that has the large 1inch wide curved hose that goes from
the pair valve to large black metal tube under the intake, back to the air cleaner box.

It sounds like the hose maybe unseated or worse the plastic on
the pair valve is cracked and leaking.

The valve only functions above certain rpm conditions and opens and sucks in
unburnt gases through the valve back into the intake via the large hose.

It leaks it sounds like Darth Vader's helmet rolling down a flight of stairs.

Been there done that

havenoclu

Do you have a pic or maybe where I can reference it in the service manual (the downloadable one). Thanks for the help!

BillaBongo

Sure thing.

I corrected my post, it goes to the large black tube under the intake
back to the air silencer box, not the intake itself.

Just look behind the back spark plug and on the passenger side and you will see the valve, the large hose
connects to the backside.

havenoclu

Thanks. It definitely is the PAIR system. Going to continue in this thread:

https://www.yotatech.com/forums/f116...inside-237611/