So I have an 89 4runner with the 3.0. I had a burnt valve replaced about 3 weeks ago. The mechanic replaced the knock sensor wire when he had the head off. He did not replace the knock sensor to my knowledge. After disconnecting the battery, the comp was showing a code 11, "momentary power interruption to the computer". I tightened down the battery terminals and checked the main grounds. The computer came back with a code 52, which is where it has been ever since. It sure feels like something isn't right under there. Immediately before the problem started, there was a coolant leak in one of the lines that runs through the throttle body, which leaked a sizable amount of coolant onto the lower intake plenum.

As per some of the other posts, I checked the connection between the wire sticking out of the plenum and the main harness. I cleaned up the connection with some sandpaper. The code still came up. The questions are:

Could the coolant leak have got down there and fouled the sensor?
Or is it probably just the sensor going bad because that's what they do?
Hypergrounding? Will it really work? Saw a few interesting posts...

Next round...Does the timing belt need to come off to change the sensor?

Thanks in advance for your help, everyone.

 

Yes the coolant could have caused the sensor to fail
shouldn't but yes could have
Yes the timing belt has to come off.....

HYPER GROUNDING...can help A LITTLE but the average yota will see no gains in power or preformance....works great if your AM radio is more static then station.....

 

How to check knock sensor

Warm-up engine to normal operating temperature
Attach a timing light with advance indicator and a tachometer
While operating the engine at 2,000 rpm, check the ignition spark advance and calibrate the timing mark to 0°TDC.
Using a wrench or small hammer, tap the exhaust manifold and observe the timing marks.
The ignition timing mark should move in the retard direction, depending on the intensity and speed of the tapping.
If the timing mark does not retard, turn the engine off and check the wiring between the Knock Control Sensor and the ECU. Locate the Knock Control Sensor, (on the top, center of the engine block), and ensure that the connector is secure.
If no problems are found, replace the Knock Control Sensor and repeat test procedure.
If timing still does not retard, replace the ECU.
Disconnect timing light and tachometer from the engine.

 

If you just had the wire replaced, I'd say it's gotta be the sensor itself. I had the same thing, but it just ended up needing a new wire. That sucks, though. Those suckers aren't cheap. Let us know what you end up doing & how it works out!

 

Recheck all your grounds and possibly add a few more. I added one to each cyl head and also the lower intake manifold using 8ga wire. It solved my knock sensor problems. I tied all my additional grounds to the neg battery terminal.

 

One dealership quoted $77

I bought it at another for $13 (Bob Bridge Toyota, Renton WA)

 

For the sensor?!? I got quoted $210 or so! The wire cost me $10!

 

Agreed, the best price I found on the sensor was $160. If the sensor is that cheap, I'm heading to Renton!

 

My bad. I was talking about the wire.

With the number of dead 3.0s out there there should be a used sensor somewhere.

 

Yeah, I got a quote for $50 for a used sensor at the local wrecker. Might be worth the savings, but who knows how many more miles until that one goes out?

 

My knock sensor came in yesterday for my 3vze. Bob Bridge will sell them to you for $129 and change provided your not local. Thay charge about 60% of retail to mail order customers. The wire was $7 if I remember correctly.

http://www.1sttoyotaparts.com/

you may have to call them for part numbers.

 

So I tried a few things this weekend. After removing a nonfunctional security system and electronic trailer brake controller, I went through and recheckd all the grounds again. I then added a direct ground to each cylinder head, one to the upper intake plenum, and one to the computer. This had no effect. Code 52 still showed. I found this post and tried the test. It showed that the sensor was good. I then hooked up the timing light and my ball-peen hammer. The sensor was not working. So, I'm going to grab a sensor at the local pull-a-part and tear into it this weekend. I have read that the 22-re knock sensor is compatible. Can anyone confirm this?