elvis

Need a touch of help here; I only have one 86; and one 93 22RE and no spare ECU \ EFI harness. Nothing local to compare to.

Problem:
My 86 22RE 4Runner displays a code 12; Knock sensor. I have done all of the typical items to fix it but have hit one small snag.

I have conquered all EFI error codes but one; code 12: Knock sensor. It does come up only after revving past 2500; and as the revs drop back to idle.
I have:

1. Relocated the sensor to the bottom of the block (I did that on my 93)
2. Found it was loosely installed into the standard location, but crunched it down to 40 LBS torque when I relocated it.
3. Repaired a crispy connector (Looks like the PO had a bad day installing the engine; It looks like there was a small fire.)
4. Ran a replacement sensor to ECU wire for the knock sensor using shielded cable and grounded one end to the ECU body and one to the body of the Knock sensor. (Cable intended for medium frequency electronic signals) NOTE. my 86 was not a shielded cable from Toyota; this was a tip from the forums
5. Added additional ECU to battery and engine grounds
6. Swapped the Knock sensor from Flea (93 22RE) I expected it not to clear the code as I read on a post that 85-87 are one design, 88 is by it's self and 89 to 95 are the same design. (Can anyone verify if one from my 93 would indeed work?)
7. With the knock sensor out of the truck and using a high end oscilloscope it is showing it does generate AC voltage and it is somewhat linear in response. (The harder I tap it; the higher it generates and up to 3.0 VAC)

So; here is my dilemma.
I do not have a 1986 FSM; but do have the 85 FSM PDF. I also have the almost useless Haynes manual. The 86 FSM is not available for download from Toyota.. I looked
The FSM and the Haynes manual show the same knock sensor connection point at the ECU but my 86 is connected differently. It (The connector) shows no sign of the wire being moved (No scratches on the connector)
Can someone with an 86 22RE non turbo look and verify for me where the knock sensor is connected on their ECU? (Or verify with a 86 FSM?) A scan of the pin-out would be appreciated.
See attached image; from the 85 FSM. (This also matches the Haynes manual)



I have noted where my knock sensor is wired. Any assistance would be appreciated. This one bug is keeping me from transferring the title; inspection and getting it on the road.

Thanx in advance.

elvis

Update: I checked the voltage on the knock sensor wire (As I found it in pin number 3) on the 86. It showed 5 VDC from the ECU (Not what I would expect as the Knock sensor creates VAC, and requires no supply voltage). I tested the same wire on 93; and it showed no voltage from the ECU; but did show VAC when the engine is revved (as I would expect as it is an input and not a temp or TPM sensor)
I am going to move the wire on the ECU to where the FSM specifies (pin 2).

BUT; if anyone is under their dash on a 86 non Turbo 33RE; I would appreciate checking for me.

(I am sure no one wants to smoke their ECU including me)

Thanx in advance.

4runnerx3

1986 FSM

elvis

Thanks for taking the time to scan it and post it up.

Yours matches the online 85 FSM. I can assume mine was mis wired.

OK; back to the drawing board. I will let you all know what I find..

elvis

OK; I feel silly. The Knock sensor and the AC thermo cut out switch wires were reversed (I purchased the Runner with a rebuilt engine) It could have happen then as I has 3 or 4 codes when I purchased it.
I also swapped the early EFI plenum with one from a 94. I probably swapped the wires at that point; but I am not sure)

Silly mistake but why Toyota used the exact same connector is a mystery.

Thanx for all of the help (And no; I did not just figure it out... I was lazy in posting the fix )