Hi All
Being new to the world of diagnostics I was delighted to diagnose a faulty knock sensor on my 2001 XK8.The fault resets but comes back after start up so a new one in on the cards. Looking through Ebay it would seem that the newer ones (09 onward) look similar,seem more plentiful and cheaper, I wonder also if they might be a bit more robust as well. The lead is different but maybe it could be grafted in. Anyone tried this before?
Many Thanks
Pete

 

Knock sensors can vary in sensitivity, output voltage and frequency response characteristics. You cannot assume they are all interchangeable. Making substitutions like this is inviting the potential for very difficult to diagnose problems.

 

I suspected that might be the case. It would make life interesting for a future owner. Suppose I could sell it to someone I didn't like. Oh well, back to the dealer, I'm getting to know the parts man quite well.
Thanks for the reply
Pete

 

Strange tale--

Shortly after factory warranty expired I developed and very mild, sporadic RP - warning light but no dash message, with code P0333 - left bank KS. It would come and go erratically after about 5 engine starts. I replaced the KS but it persisted. Returned the KS to the dealer and replaced it again. Problem still there. I suspected a problem somewhere in the harness but not willing to devote lots of time ($$$$) tracing it down I decided to live with it. That was in year 2003.

Fast forward to 2012: My alternator bearing died and I replaced the alternator. MIRABILE DICTU!! The KS problem disappeared, never to return.

Go figure!

Sam

Incidentally, I replaced the KS both times without removing the intake manifold as recommended by Jag. It can be done with a nut driver and some grease in it to keep the nut in place. Patience is the only requirement.

 

I found that the knock sensors and washing the engine compartment are not compatible.

 

Where is the knock sensor(s) located? The knock module on my old Corvette was at the underside of the ecu and easy to get to and change. I did so when I installed some roller rockers that made the valve train a bit noisier requiring a different knock sensor/module.

Doug

 

Underneath the intake manifold. There are two sensors, one for each bank. They can be reached and changed by some creative manipulation and bending a tool or two plus the use of forceps. Still lots easier and quicker than r/r the manifold IMO.

Sam

 

Sorry, I just noticed that you have an XKR -- may be quite a bit more difficult -- I don't know.
Sam

 

I also believe I got my terminology mixed up. My old car had knock sensors that were attached to the engine somewhere and there was also the knock module which the computer used to interpret the noise picked up by the sensors. I assume the set up in our cars is similar?

Doug

 

Thanks for the info Guys. I took the old one out today and rang the local dealer to order a new one. I could hear giggling in the background and the rubbing together of hands. Picking it up tomorrow so all my problems will soon be over Hmph.
I tested the resistance on both sides and the good side was nice and steady while the duff one jumped all over the place. All will be revealed
Thanks
Pete

 

I couldn't get the pass. side ks up over the stud because of a lack of clearance between the stud and the intake manifold. How did you guys succeed? Driver's side was okay, just a bunch of fiddling.

 

Hi Mike
I used a piece of stiff wire bent over like a hook at one end and just lifted the sensor off the stud. Seems like your stud is maybe a fraction longer than mine. I noticed a kind of spline arrangement on the end of the stud, probably to grip the stud to screw it in. I guess if you could get a small socket onto the end of the stud you could unscrew it, or maybe it's partly unscrewed now resulting in less clearance?
These cars are character building if nothing else.
Good luck
Pete

 

I'll try to unscrew the stud just because I have the extra new sensor.....if it doesn't move, I'll wait for the hose replacement that I know will come.

 

Fitted my new knock sensor today without too much trauma except that the little bracket snapped off the thermostat housing so a couple of tie wraps came to the rescue. The faults cleared but the MIL is still on. I tried disconnecting the battery for a while without success. I think maybe it needs to do some miles in the next few days. What a great excuse.
Pete