I'm new to this site and need some help with my CEL codes. My pickup is giving me trouble codes 25, and 52. I have a 1991 pickup with a 22 RE with 388,000 plus miles on it. This is its second engine and it only has 50,000 on it. It has been running a little rough, sporadically missing. It has new plugs, wires, cap, rotor, fuel filter and air filter.

 

25 is fuel mix lean malfunction, 52 is no knock sensor signal above 2000 rpm for 25 revolutions.

 

So the two are probably related to different problems. Could the knock sensor likely be a loose wire? What would cause a lean fuel mixture to occasionally run bad? Oxygen sensor?

 

Figured out the knock sensor. Its not even hooked up.

 

Yeah.....check and see if the knocks sensor is even plugged in.

 

Look Who decides to show...

 

well, both the knock sensor and 02 sensor (which is giving the reading for the 25) pass through the same wiring harness....
are the two related... could be, but not really likely.

since you found the knock sensor wasn't plugged in, I'd suggest disconnecting the battery a few minutes then reconnecting it (to clear the ECU) and start driving again.

If the CEL and codes come back, come back here, then we'll start looking at what's happening then.

... and please come back anyways to let us know if things are fixed.

 

I reset the cel sensor. We'll see what happens when I drive it tomorrow - unless i make a late night trip to the store tonight.

 

I am experiencing a Code 52 on a 1991 4Runner 3VZE. Any idea where I can look for the Knock Sensor Signal circuit?

 

May be a few days before I drive it again. I don't have plans to go anywhere til I head home on Wednesday.

 

Show....? Show what? I've posted some pics. You all have seen all yer gonna see........unless Abe starts posting his pics. I caught him peering through my window this past week. Heard the dog trying to hump something. He jus'th get'sth s'tho exc'thited......


(I think Abe's got a new friend)

 

Under the throttle body area and extending out from under the upper manifold is the KS wire/connector. (The KS is actually under the manifold requiring a complete tear down of the top end 'cept the heads to get to.) Start there. Otherwise, look in the FSM posted in sticky on the main page for ECU diagrams. They'll show you the appropriate terminal for testing purposes.......ie, testing for a signal.


Okay................here's the linky poo:

http://personal.utulsa.edu/~nathan-b...e/102engin.pdf

 

Uhh, Yer face round these here parts

 

Decided to take it out for a drive. I got the same 2 codes, since I haven't done anything to the knock sensor yet. I'm hoping I can get it running better before heading home for thanksgiving.

 

I'd start looking for wiring issues in the harness around the knock sensor, checking for continuity to the ECU and shorts.

 

Seemed to have found the problem with the o2 sensor wire in that harness. Thanks for the help. Over my short test drive, it seems to run better. I'll know for sure in a day or day. Now I just have to get enough ambition to hook the knock sensor back up.

 

Boo!........