Hey all, i was on here a couple months back and had some issues with my truck. I traced them to the 3 tranny solinoids, now the mechanic is tellin me the check engine light is still on because the knock sensor is bad. the knock sensor fully retarding the motor caused the solinoids to go bad. anyhow, im trying to locate the wiring pigtail from the knock sensor to the ecu harness. Is it the plug that comes out by the drivers side valve cover and then directly into the distributor? anyone have any pics?

 

Remind us which engine.....

 

sorry dude. 3.0 v6 4x4 auto

 

The knock harness under the manifold dies all the time. It's about $10 from the dealership.

knock sensor wire at the ecm is the only shielded wire there. You can check it with an oscilloscope, but chances are the short knock wire on the engine has failed.

 

yeah but can i get a pic from someone on where the pigtail plugs into the harness? is it easily visible?

 

I ended up mounting my knock sensor to my engine lift hook on the driver's side the last time it went bad. I haven't had any trouble with it since.

I had to drill a hole in it, then tap it, but all told I think that was an easier way to go.

Are there downsides? I dunno. Maybe someone else has some input on the subject. My pigtail should be fairly visible. I'll try and get a picture for you.

 

I tried taking a picture of the pigtail, but it's under the 4" diameter air line that runs from the air intake to the plenum that covers up the rest of the stuff you usually want to work on.

It's too cold and dark out there to be tinkering on the truck. I failed.

 

Okay then. I had already planned on fixing it the same way you did......externally mount it. just trying to find the wiring harness the pigtail plugs into. thanks

 

its right below the throttle body.... pull the intake tube and it should be visible.

I would advise against mounting it externally, that pretty much renders it useless, or only useful to 1 side of the engine. if you do mount externally... I'd at least run high octane fuel.

 

I'm glad to know I am not the only one having this problem. Keep us posted! Please

 

I agree, except that at least the hook is near cyl 6, and since heat is a leading factor in detonation, if you were going to be near only one cyl, that would be the one. But I don't know if the sensor will pick up even cyl 6 too well in that position. Just dunno.

 

Here is a picture of the knock sensor and pigtail in it's installed location. Replacing the pigtail ($10) fixes the problem nearly every time, but as you can see, you need to remove the lower intake manifold to get to it. Look at it as a chance to replace the idler pulley and all the gaskets on the upper part of the engine and go for it. Definitely replace the valve cover gaskets while you're in there as they always leak after a few years and get slime all over the engine. This picture is my Mother in Law's engine and was taken last month. The valve cover gaskets get replaced every 5 years when I do the timing belt and the engine is clean and dry after 20 years.