PhilR

I just made a few repairs as I replaced the head gaskets on my 1993 pickup and I did replace the knock sensor and wire as mine didn't cause problems but the wire was bad and I read about the issues with them so to be safe, I just bought a wire at the Toyota dealer and a OEM knock sensor still sealed in the package with the Toyota part number on it on eBay.

Now, I have a code 52 and the "check engine" light comes on every time I drive the pickup on a short distance. At the same time the light comes on, the performance decreases (which is normal, I know).

I don't feel like removing the intake again just to replace parts that are brand new. What else could cause this kind of issue?

I have ordered another wire at the Toyota dealer, I should get it tomorrow and I'll plug the old sensor which never caused problems to it but I'd like to know more about that and testing procedures.

I did watch a few videos and read a few threads on this forum and else but I can't find much information to help me... Anybody has advises and suggestions?

vasinvictor

iTrader: (3)

Make sure the darn this is even plugged in. You don't need to remove the mani to check that.

edit: well unless you didn't plug the pigtail onto the knock sensor itself. Then you'll have to remove the manifold. Code 52s suck.

PhilR

I'd be very surprised if it wasn't plugged correctly! I remember having to press a bit harder than usual on the new connector to hear it "click" on the new knock sensor. I assumed that was because the parts were new. It didn't feel like I broke something however!

As for the connection to the main harness, that's the first thing I checked! I noticed that the insulation around one of the wires was cracked the wire was still intact underneath but I replaced that connector from the engine harness with another one I had, welded the wires and that didn't help...

I had to replace a few connectors that were dry. All but one injector still had the original blue connectors and the 5 blue connectors broke when I removed them (not just the locking tabs, the whole connectors!). The greenish plastic ends on two injectors also broke when I removed them from the intake and the plastic where the connector connects broke on another injector. I got 5 used injectors (of which I used 3) as well as 6 good used (gray) connectors from the junkyard to replace the 5 bad ones on mine.

There's a bit more valvetrain noise than there used to be. With 201,000 miles, it wasn't exactly silent before I replaced the head gaskets but I'm pretty sure it's noisier now on the driver side. I took care not to mix up the shims but I had the valve seals replaced by the machine shop who resurfaced the heads as well as two helicoils installed in the threads for of the cam bearing caps, I'm wondering If I reversed something by error or if they did something to cause that. And I'm also wondering if the noise from the valvetrain could cause problems with the knock sensor?

hogranchsr

I have a 95 4 runner, did a complete overhaul on engine. Installed a new knock sensor and pigtail. The thing threw a code 52. I read the post on your form and replaced the wire from the pigtail to the computer. This was well worth doing as it runs great. It still throws the code 52 but not as offten as it did before. When I installed the new knock sensor I used a gasket like a washer between the sensor and the block. I fell this is my problem (the gasket) not letting the sensor give a full signal as it might be dampened by the gasket. Does the knock sensor need a gasket? Or do I have a bad sensor? Thank you P.S. I did use a sheilded cable as recomended