wheels313

Hi, First off...I love this site as its Full of Great Info and very knowlegable guys...THANKS!!! I have a 89 4Runner that someone in the past put a 93-95 motor in. They cut the harness and added the plug for the newer style knock sensor to match. I had to pull the intake for other reasons but decided to put a new Knock sensor and wire in while there. I put the 89 sensor and wire on and then switched back to the 89 plug on the harness. I sodered the black wire and then shilded it from the coax wire on the outside but now I am getting a code 52. STUMPED!

93toyrunner2

Take a voltage meter and check continuity on the wiring from the connector (black wire you soldered) all the way to the KNK (B5) port on the ECM. I would bet you have a short. Also, how did you shield the wire from the the coax wire? Any pics of this? I used actual coax to rerun my wiring for the Knock sensor, soldering the actual center wire to the black wire on the connector, and then separating the grounding wire mesh near the outside of the coax cable, installing each wire separately through vacuum hose and high heat electrical tape to insulate. You do not have to insulate the first 2 inches, but the remainder all the way to the ECM must be done.

wheels313

I will check the ohms but it was perfectly fine prior to installing the new plug, wire and sensor. I Rolled the shielding back on ends of the coax, sodered the black wire, heat shrinked it, black tape then rolled the shilding back over top on both ends till it made contact and then black taped the coax shielding.

wheels313

BTW, thanks for the assistance.

93toyrunner2

I bet when you moved your intake that you had to remove the injector rails and the wire harness over out of the way. When moving old brittle wiring, you can have problems like what you are mentioning. Check the wiring continuity between the ECM and the sensor plug. let me know what you get.
(meant continuity above, not OHMs)

wheels313

I am going to go check the resistance and will let you know shortly.

wheels313

Toyrunner, I just checked and have full continuity and ohms is .012ohms so I am wondering if the new knock sensor is bad or if i may have somehow pinched that wire in the manifold somehow. is there a way to check the sensor resistance?

93toyrunner2

More than likely you pinched the wire in between the head and the intake. From my experience, the knock sensors never go bad, just the wiring.
Did you test at the connector pin, or at the wire before the connector?

wheels313

I tested it both at my solder joint and at the actual plug...here is a crazy thought, I only started it for about a minute and got the code and shut it off. I wanted to make sure it started and ran prior to putting in the coolant and radiator....do you thing that had any affect on the situation?

93toyrunner2

Clear the code by removing your EFI fuse for a few minutes, and try it again. As far as I know, you have to drive the vehicle at 10 mph and above for it to signal correct codes.

wheels313

I went ahead and put it all back together today. filled her with coolant and thought I was golden..then I took off down the road and it spit sputtered and coded 52 again. I am going to check the timing since I put a new belt on and clear the code again to see if that does anything.

wheels313

not looking forward to tearing it back down again.

acorvet

Just for the grin of it.. I have a 92 3VZE and had code 52 for over 2 years (Not my daily driver). I replaced the wiring with quad shield coax, tested continuity, new pigtail, changed ECM (Not with a new one), installed new knock sensor (purchased from parts store_. Still had CODE 52 until I purchased a new Knock Sensor FROM TOYOTA. Yes, I have a former Toyota mechanic listen to my store and he said the only thing he would do different was to buy the TOYOTA brand sensor, as it is a very intolerant system!

wheels313

Acorvet....IRONICALLLY you hit the nail on the head. I tried everything imaginable before making the move to tear that dreaded B@#$% back down again. I bought the knock sensor from a guy on Ebay in a TOYOTA bag and it WASNT a Toyota sensor. The PRIk even said it was OEM...NOT. needless to say, I tore the 3.slow back down put in the sensor from Toyota and no more code 52. LESSON #1 never buy a knock sensor thats buried in BFE with anything other than Toyota...I should have known that $50. for a $210.00 was to good to be true. Thanks again gents for your inputs and assistance, the beast is alive agtain.

gobble4me

I have a 1995 Toyota 4runner 3.0 4x4 5 speed That has a slight spark knock around 2000 rpms and immediately the check engine light appears with a code 52 (knock sensor) if engine is shutoff and restarted check engine light is reset until driven or engine reaches 2000 Rpms. I've tried retarding the timing but doesn't help. I also took another knock sensor and pig tail connected it to the main harness and mounted knock sensor on lift hook like I've seen done on this site, hoping it'd show if my sensor under intake was faulty or not but It acted the same with the sensor on the engine lift hook. Any suggestions would be appreciated

93toyrunner2

Code 53 is not the knock sensor, it is the ECM. Use the link in my signature to get yourself a copy of the Factory manual.

gobble4me

I've called myself searching that fsm and the-roo.com can you direct me to which pdf its under. I have another ecm from a donor t4r I have maybe I should swap them out

93toyrunner2

http://www.ncttora.com/FSM/1990-1995...e/diagnosi.pdf

gobble4me

thank you for the info but my code is a 52 thats the only code and im getting sorry don't know why I stated (53)

93toyrunner2

Well, now that you edited the code 53 you posted earlier to a code 52, the above no longer applies. Look up the code 52 in the diagnostics in the FSM MFI diagnostics section, and follow the diagnostic procedures to find your problem. You probably have a wiring issue with the brittle wiring for the knock sensor, and running a continuity test from the sensor wiring connector to the ECM would help diagnose this.