I'm getting a lot of knock retard, and would like to verify that my knock sensor is working properly.

Can you explain how I go about testing it?

 

I heard their was actually some type of mic inside it. I would log a run and lightly tap on it with a wrench to see if you get retard.

Jeff D.

 

just got my service manual and can help you out, i'm at work, manuals are at home.

You have to pull the harness off the sensor, measure the voltage, then measure the resistance from the center pin on the knock sensor to ground, I will post the real deal when I get home.

I know once you start the motor, you switch your dvm to ac voltage, and you should see around 3-4 volts ac on that line, but wait till i get home to get you the real procedure.

 

Thanks Hotwire, I really appreciate it!

 

alright, pcm sends 5 volts dc to the knock sensor, disconnect knco sensor from harness, turn key to the on position, do not start, and measure from knock sensor wire harness to ground.

if around 5 volts, measure resistance from knock sensor terminal to ground. should be between 3300-4500 ohms.
I'd measure from terminal to body of knock sensor, if good reading, then go from terminal to block to see if knock sensor body is grounded well to block. if reading changes, try reinstalling the knock sensor for better connection to block.

if no voltage from wire harness look for short to ground, or open wire.

turn key off, pull connector d (blue) off of pcm, turn key on, check for voltage at pcm, refer to shoebox's site for the pcm pinout. It's D22. If you have voltage at pcm, it's ok. Measure from connector D to ground, if you have any voltage, wire is receiving voltage from somewhere it shouldn't. open up harness and look for frayed wire sheathing.

if you have voltage at pcm, but no voltage at harness, then you have shown that the all the above connections are solid, so you either have a faulty knock module, intermittant connection, or faulty pcm.

sorry i jumped around, trying to get out to the garage to get my truck on the road.

once you read it over and attempt to do it, you'll understand what you are trying to accomplish.

Good luck!!

 

I thought the 93-95 KS was 4,000 ohms, and the 96/97 piece was more like 100K ohms?????? I could be wrong, but the data posted above is identical to the 93 and 94 manuals that I have as far as sensor resistance.

 

Right, Fred. OBD-II knock sensor resistance range is 93K to 107K ohms.
OBD-I is 3300-4500 ohms.

 

10$, damn I just paid 56$ at a local shop, they are usually the cheaper shop 2.
A big giveaway that my ks was shot was the trouble code :P

 

Mines is messed up, comes on after start up, usally after the cars been sitting. Gets a code for the ESC. Been that way for years, as long as it doesn't stay on all the time its cool. Usally just turns it self off. Runs like crap when its on for the minute or two that it is on but the car sounds so damn awesome.

 

If it only comes on for a minute or so I would check your wiring and connections, possibly brush off the connections if needed. Or check the wire to see if its stripped in anyplace to see if its being grounded against something.

 

Neil, what does it sound like? I am fighting with my lt1 right now, it won't run worth a damn, 7 cylinders rich, 1 acts like it isn't firing, replaced whole ignition system, adjusted valves, etc.

 

Hey guys, thanks for clearing that up. I was using those figures and procedure out of a 94 Helms Service manual.

And, I think I found out why I'm getting a ses light and code 43... I have a 94 motor, knock sensor is grounded, getting 5 volts to the harness.. but the sensor reads 100k to ground. Some #*)$^*(&%^*(#&^$# at the junkyard must have busted it when they pulled it and just picked one up and stuck it in there. One problem down, 40 to go.....