Knock Sensor Repairs - What did you do?

[gamefreakgc]

In what seems to be a fairly new phenomenon, I've got a code for Bank 2 knock sensor. It seems like these harnesses and knock sensors are reaching near the end of their ageing cycle and need to replaced. This is a low-mileage replacement JDM engine that I though would be fine, but obviously I was wrong. I did not replace either when I swapped engines.

I would like to know what you had replaced and the success rate of each. Money is sort of tight right now but I can make it work to replace both the harness and sensors. Please only vote if you've had the job done.

Also, I welcome links to cheap OEM knock sensors. So far McGeorge is the best prices I'm seeing.

 

[RS Dude]

My harness went bad only, but I replaced sensors because I bought them for cheap. All is still well ever since!:guitar2:

 

[gamefreakgc]

My harness went bad only, but I replaced sensors because I bought them for cheap. All is still well ever since!:guitar2:

Where did you buy them from?

 

[RS Dude]

Where did you buy them from?

Bought both off ebay from two different Toyota dealers.

 

[Dieselchessy]

I replaced just the harness when I installed my JDM. The old harness was very brittle.
They also sell sensors. The harness I received looked the part.
I had no issues prior to replacement or since.

GENUINE TOYOTA 4RUNNER TACOMA TUNDRA 3.4L KNOCK SENSOR WIRE HARNESS 82219-34010 | eBay

 

[Joelzy]

i was rebuilding and the harness pretty much disintegrated in my hand. they weren't cheap, i wanna say i paid 80 bucks a pop for OE with my buddy's discount but i had already blown my rebuild budget by then so another 200 bucks for those and the harness was worth not having them pop later :yield:

 

[vipergrhd]

Replace all

Just replace all of it, do it once and call it good for another 20 years.

 

[MikeDiehl]

So, I also have a knock sensor related question.

My 1996 4Runner started displaying a check engine light indicating an issue with the knock sensor on back 1.

I took everything off of the engine and pulled and tested the knock sensors.

Both sensors show an open circuit between the terminal pin and the sensor chassis. (good)

When I plug a volt meter into them, one sensor shows about 2 mill-volts and the other shows about 6 mill-volts. In both cases, this voltage increases when I strike the sensor with a wrench. (good)

It looks like I have 2 good sensors, so I checked the wiring harness. It showed only a few Ohms of resistance from one end to the other. (good)

As it turns out, the replacement wiring harness I purchased on Amazon came with _2_ knock sensors!

So, (finally?) here's my questions:

What should I do? :decision:

1. Put the original OEM sensors back in and simply replace the harness?
2. Put in the new, non-OEM sensors in with a new harnes?

Given that I also found a heater hose that had sprung a leak under the intake plenum and filled the cavity with rusty coolant, could that explain why I got the CEL even though everything seems to test out as good? :decision:

What else should I check in order to clear the CEL? :decision:

What else should I consider replacing while I'm this deep into this engine? :decision:

Am I missing anything? :decision:

Thanks in advance,

Mike.

 

[Dieselchessy]

Replace the valve cover gaskets, intake gaskets, knock sensors and harness, PCV valve, clean the IAC and throttle body, plugs and wires, the 2 coolant lines to the AIC, the vacuum lines to the intake(injectors), the fuel pressure regulator and its gasket, all the injectors should be cleaned and tuned, and all the injector O-rings and rubber bushings should be replaced.

That should just about cover it...….:lmao:

 

[gamefreakgc]

Replace the valve cover gaskets, intake gaskets, knock sensors and harness, PCV valve, clean the IAC and throttle body, plugs and wires, the 2 coolant lines to the AIC, the vacuum lines to the intake(injectors), the fuel pressure regulator and its gasket, all the injectors should be cleaned and tuned, and all the injector O-rings and rubber bushings should be replaced.

That should just about cover it...….:lmao:

Luckily I did all that when I swapped engines . I just didn't remove the intake manifold due to having to replace more gaskets.

 

[Dieselchessy]

Luckily I did all that when I swapped engines . I just didn't remove the intake manifold due to having to replace more gaskets.

It’s been my experience that those metal gaskets with rubber edges that seal coolant passages are prone to corrosion. I expect you’ll find a pair of corroded gaskets when you remove the intake manifold.

I removed the manifold primarily to replace those gaskets. The knock sensor harness was a secondary item for me. I also did the seal for the stainless coolant pipe while I was in there. Easier to do all that with water pump off so you can clean out any debris that falls into the coolant passages.
Also a good time to clean carbon off the backside of the valves.

Everyone has a different set of experiences that drive their decisions.

 

[Ghostrider]

Do you have to pull the intake manifold for this? If so - grrrrr - just had the valve cover gaskets done last week

 

[Dieselchessy]

Do you have to pull the intake manifold for this? If so - grrrrr - just had the valve cover gaskets done last week

Yes, but if your not experiencing problems don’t worry about it. These engines will go a long way without issues. Especially if oil and coolant are serviced at least half as often as they should be.

 

[gamefreakgc]

So yesterday the code cleared itself (was still stored in the ECU) for about 15 minutes and then came back on. I'm thinking that's an intermittent connection from the harness?

 

[fan of fanboys]

Knock sensors and harness
Spark plugs and wires
Heater hose
All three serpentine belts
Radiator coolant hose
Timing belt
Water pump
Radiator and new antifreeze
Trailer wiring harness
Camshaft seal
Intake manifold gasket
Thermostat and seal
Valve cover gasket
PCV valve and grommet
Radiator cap
Couple oil cooler hoses

replaced all that wit new last week. CEL is gone

 

[3bears]

I had to do my knock sensors, and only used toyota parts....to many threads out there on cheap copies that crap out. I dont like doing things twice, and with the age of this truck and miles (245k) anything that was replaceable....gaskets, hoses etc were replaced esp if it was under the manifolds. I also did vc gaskets, wires, plugs, cleaned maf, ICV etc. Also the driver side wire harness loom cover under intake was pretty brittle and crumbled under my hands, so wraped the wires in rescue tape ( high temp stuff)


CHEAP SHORT CUT
I wont look it up to link, but there is a guy on you tube, that made a metal bracket, mounted 2 knock sensors to the bracket, plugged in new harness to plug end near top radiator hose.. bolted the bracket to his alternator bracket I think, .all of this outside of engine and without pulling anything apart. He did this to avoid doing the work and turn off his codes. Of course this bypasses the reason to have knock sensors...but like I said he did it to avoid doing the real work. This not only clears codes, but I was told that if the truck reads this code long enough it will go into limp mode, and I sure did not want to go into limp mode on my move.
I saw this as my knock sensors went bad ( ended up actually being the harness) about a week before moving to alaska from Oregon, and actually thought for a few minutes doing this for a temp fix for my move. Reality struck, and I ordered all the parts and pulled a couple of long days and nights to get it all done before the move.

 

[gamefreakgc]

Ok, I've got a bit of a conundrum now. I replaced the harness (the old was was in very good shape though), fired it up and the code is still on. Replaced both sensors with known good ones (I took them off a running engine and was planning on selling them) and code pops back on. Not only that, now I have codes for Bank 2 and Bank 1. I've ordered an ECU to swap out to see if mine took a dump.

Anything else I should be looking at?

PS I can do a knock sensor repair in 2 hours flat... so not a total waste of time for me. Plus we all seem to have more time on our hands as of late...

 

[gamefreakgc]

My new knock sensors came in and I put them in. Man, I could open a knock sensor repair shop, I've got it memorized. 2:15 and the whole thing is done.

Codes are gone. Need more driving to know definitively but sensors were the issue. Odd that they failed with only about 60,000 miles on them, but perhaps it's age that kills them and not miles. So intermittent KS codes can mean the sensor as well as the wiring. For me it was the sensors.

 

[19963.4lsr5]

It still annoys me that Toyota doesn’t use them below 3000rpm.

When I was going through my CJ phase I found a stand alone knock sensor setup that used a GM sensor that could retard ignition as well as indicate if it was present.

Edit: you would need three of them to be effective though.


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[Devbot]

Hey, just tried to tackle this yesterday.
Personally my trouble started with a combination of P0171/P0325/P0420. Initially suspected a vacuum leak and couldn't find one, so decided to replace the MAF and that took out P0171 and P0420, but P0325 still persisted. When cleared, the CEL will turn off until a steep grade or other means of heavy acceleration.
I read about splicing the two sensors together to trick the ECU around the code and that this worked for many people - thinking this would be the best step since it was the least amount of work and money, I gave it a shot but to no avail. CEL still on.
Next weekend I'm just going to replace the sensors and harness together and call it good; you might as well if you have to open everything up just to service either one. Knock sensors are a headache that will NOT go away like other codes.

(car is a 2000 SR5 at 282k)