Ok 90 4 runner 4x4 3.0 5speed 120k on it. Bought it last month clean and has total chaos long travel kit on it. had a little bit of a high idle and a hole in the muffler and the check engine light was on, it ran good and i figured the cel was probably the o2 sensor as it looks like its the original as well as the exhaust that is falling apart. drove it for a month with no problems then while driving it just stopped and would not restart. Found that the timing belt had jumped a couple teeth. tore it down found a 8mm nut had fallen inside the timing cover and wedged itself at the bottom of the cover between the belt and cover, probably when the previous owner did a headgasket, he said it was done a thousand or so miles ago.
I replaced the belt, tensioner and pulley got everything buttoned up and the timing marks where all good turned motor over a few times and all marks lined up. turned the key and started right up but was idling crappy and was missing a little. put a timing light on it wjile I had the jumper in place. found the timing to be probably 20 deg btdc, turned the dist and if I went any lower then 15 deg the engine wanted to die as the idle became rough. dist is not out a tooth as i tried it one tooth both forward and back would not even start. now I have a cel code 52 and a coolant leak from above the t stat housing looks like it's coming from headgasket. this thing is going to drive me crazy......HHHEEELLLPPPPPPPPP PPPLLLLEEEAAASSSEEEE........

 

Well, start by replacing that knock sensor [and make sure you take a look at the wiring] and fixing that coolant leak.

No point in checking anything else til you fix what you know is wrong.

And, FYI it's a good idea to at least find out what a MIL is when it comes on, instead of leaving it til the engine won't run.

 

Set the timing marks on the 2 cam pulleys and crankshaft to TDC (0) and then pull your distributor out. Line up the distributor rotor so that it is on the #1 cylinder when you put it back in. Follow the instructions for reinstalling the distributor from the FSM (link in my signature). Don't assume the distributor is in correctly from the previous mechanic, make sure it is in correctly yourself. Coolant leak from above the thermostat housing could be coming out of the oil cooler bypass hose that connects at the top right of the water pump, or even the water pump itself. You have it apart, why not inspect and replace the water pump while you are already there.

 

^That may be part of your problem, but fix that knock sensor first.
Your dist being out of time can't cause a knock sensor code.

 

Also, did you jumper terminals E1 & TE1 in the Diagnostic port on the passenger side fender well before you checked timing?

 

replacing that knock sensor

 

Well? You left us hanging...

 

Ok when I had the timing belt out i checked the water pump and it was good, going to spray off the area of the t stat housing it almost looks like it's coming from the headgasket area. picking up a knock sensor this week and will put it in this weekend, i saw where a guy had his mounted on the top of the intake, looks like I have to pull the intake to get to the old one on the back of the engine. everything timing belt, timing etc was done to fsm specs. I think there may be a swap in my future.
can you bypass the knock sensor to see if that clears up the problem?

 

you can bolt a new sensor to the engine hook in the hook loop area with a bolt that fits the thread (12mm x 1.25 I think), tighten it down good so it doesn't fall off, and connect a new pigtail to it, then connect it to the wire loom off the drivers side. Not recommended for daily use!

 

so no way to bypass it to see if it is the problem, can i test it, looking at fsm for info hate to spend a hundred bucks and not be able to return it if thats not the problem. how does it differentiate knock versus exh leak tapping valves noisy fuel reg or injectors?

 

if I have en external oil cooler can I get rid of the stock oil cooler with the hose to the water pump?

 

It's usually the pigtail, NOT the 02 sensor.

Yes.

 

I picked up a knock sensor to use for testing at the local PullaPart yard, cost me $4. The pigtail was crusty, so I got a new pigtail at the Toyota dealer - cost $21.

 

is the knock sensor accesable without pulling the intake ? how about the wire can you change that without pulling everything apart. This thing is driving me crazy, I bought it to drive around the desert and I keep seeing things that need to be replaced, you really don't want to break down where i'm going. I was looking for the knock sensor and saw on the water bypass part on the back of the engine one of the hoses looks like it is about to brake it's all corroded and I don't see an easy way of getting to it.
My goal is to pull as much stuff that is not needed to make the motor run and have less stuff to go wrong while out wheeling, I don't need a/c, heater, cruise control etc. Heck it looks like there are 4 or 5 sensors on the water bypass alone. and one of the hoses runs under the intake, looks like I'm going to have to pull it off to sort everything out,
Parts I need to replace so far are the knock and the pigtail,the hose on the bypass or maybe I can eliminate it, the fuel pressure regulator was making alot of noise so while I have the intake off I'm going to replace it. I don't want to put alot of money into the 3.0 because I want to swap in something bigger.

 

It's pretty deep in the valley. intake removal necessary, unless you have REALLY skinny hands and are a contortionist.

 

Even if you ARE a skinny contortionist, you will have to remove the plenum & intake manifold~

 

WOW this is going to drive me crazy, I took the intake off and I don't even think they have the knock sensor hooked up it looks like they put a butt connector on the wire and bolted it to the block like a ground....on the back of the engine there is a coolant hose that goes to a manifold with about 4 sensors and it looks like it has a metal line running under the intake manifold to the front of the motor. this looks like its leaking as coolant is coming out near the water pump but its not from the water pump.

I also want to bypass the heater and remove all the hoses associated with it.
I picked up a toyota V8 thinking I would put it in this runner but I am just going to keep the 3.0 and put the V8 in a 4 seat buggy with longtravel based on a toyota chassis.

 

Hi, I've also got a 52 code, but can't find the location of the knock sensor in either of my manuals (haynes and ncttora on line.) Can someone direct me to the location of it and/or where I might find it in a manual?

Thanks

 

the wire comes out by the throttle body and the sensor is under the intake and plenum, you have to pull the whole front and top of engine apart, you should plan on doing timing belt and water pump also because your going to have to pull it all apart to get to the sensor.

since mine was rigged and just grounded to the motor could this damage computer

 

i dont think it will, and yeah its not fun replacing the knock sensor i just did mine, all in 5 hrs, just try and find one at a junk yard after all they want 234.00 for one at autozone.