So I know there's lots of code 52 threads, but mine seems to have different symptoms than most.

I just bought this 4Runner (89 sr5 v6) 3VZE a few weeks ago, and no check engine problems until a few days ago.

Researched how to check the code, and came up with 52.

However, the CEL appears intermittently. The check engine light will not come on for several miles at times, an other times it will come on right away.

This is leaning me towards it being a bad electrial connection to the sensor itself. Anyone else agree?

First step in my opinion would be check the wiring to the knock sensor and replace as necessary, and replace the knock sensor while I'm in there as well.

Any other parts I'll need while I'm in there? Intake Manifold gaskets? anything else?

Thanks a ton for the help!

 

You know you have to take pretty much the whole top end off right. The wire is 16 bucks from a dealer. The dealer also recommends there mechanics replace the sensor and the wire when the top is off. I replaced just the wire and my light went away. Yours is a 52 which means its prob just the wire.

 

It is very very uncommon for the knock sensor itself to go bad. It's the little pigtail harness connected to it that is the culprit 99.9% of the time. What happens is it builds up a lot of heat down there, and the wire's insulation deteriorates and becomes crispy like. You'll need the wire itself, and a set of intake gaskets. Honestly while you're in there, if you haven't done it before, now would be a good time to replace your injector seals if you haven't before.

If all you want to do is replace the knock harness, you can legitimately do it in an hour and a half if you take your time. But if it were my truck, and I was in there anyways, then I'd be replacing the injector seals, valve cover gaskets (make sure to seal the cam caps in the back!) and anything else in the near vicinity. Do it all in one trip and save yourself the hassle of having to take all of that off again for a good while down the road

 

Thanks a ton for the input!

WHew! Cam caps and all eh? Definitely good advise with the mileage on my motor (170k).. In order to replace those seals, I'll have to remove the t-belt and cams, correct? (with holding tools etc)

Good advice taking care of the valve cover gaskets and injector gaskets. Do the injector gaskets tend to shrink and crack on these motors? Would you recommend getting new injectors all together, or different # injectors?

Sounds like I'll be tackling this after the BMW pan gasket and thrust rod bushings

 

You won't have to remove the tbelt and everything. The valve covers are the black things on top (like where you dump your new oil into it). Definitely make sure you take the cam caps off of the back of the heads (there are 2 10mm bolts and a ring looking thing holding them on) and clean them up real good, and seal them with fipg. Otherwise they WILL leak!

The injector seals don't really tend to shrink, more oflike they just turn from what once upon a time was rubber, and are now more like plastic and then they will tend to crack and leak. Stick with your original injectors, there's no reason to replace them. There are 2 ways to clean them though, first is to remove them and send them out to have them cleaned and balanced. More expensive and takes way more time. Your second option is to get a can of what smells like pressurized cat piss. It is a detergant that you will disconnect the fuel lines from the injectors, feed the can into the injectors, and run the engine for (usually) 15-20 minutes until the can runs out. Most dealerships charge around a hundred bucks for this service. 2 or 3 cans of that stuff run through will make a HUGE improvement.

Edit: you may actually have to partially remove the timing belt to get the center idler pulley off, to get the lower intake manifold off. Honestly work has been kinda crazy with all of the gas pedal recalls lately, and my brain isn't working quite right. But if you use a couple clamps on the cams to hold the belt so it doesn't slip off a tooth on either of them (a white out pen to mark the belt and where it is at on the cam for double accuracy doesn't hurt either) and you can rotate both of the cams inward towards the idler pulley, remove the 4 bolts and pull it off without actually really touching the timing belt. You don't need a lot of slack, just enough to take the tension off the pulley so you can pull the water pipe off. You'll see what I mean.

 

oh, and make SURE not to overtorque the valve covers when you put them back on. they ARE plastic and WILL crack if you tighten them too much! Definitely a job for a 1/4" drive ratchet... not your makita impact

 

Haha, wish I had a makita impact!

Dude. Thank you so much for the input! When I start this project I'll definitely be coming to you with any Q's!

Right now i've got the bmw on blocks, subframe removed, oil pan off, etc etc.. so as soon as this ones back up, on to the next!

 

No worries, be happy to help ya.

I couldn't live without my makita