it wont matter if it's hot or cold... it wouldnt change much if at all. measure from ground to each pin... you will find 0v, 5v and then ~.75 v... 0v is gnd and the 5v is power... measure the .75 v line to gnd and set the voltage by turning the tps one way or the other until you reach .7~.75v... then it's set to perform it's best. this signal tells the pcm where the throttle position is, if the pcm thinks it's not open when it is, it could create a lean condition like you describe. set it and get back to us with your results...

 

Could be timing Chain, but The thing is yours doesn't Knock all the time only when cold right? Well It's not that than. But 1997 didn't come with the tensioner unless you put it in.

 

Thanks Steve, will report back maybe this weekend.

When the truck first started making the noise my dad took it to the shop and that's what they told him it was, which I immediately dismissed because of it going away off-idle (and because I didn't feel like tearing the front half of the engine apart). But now I'm willing to consider anything. This is a magnum engine with a double-roller chain, though, so I can't see why it would have such a short life if it were the problem.

 

Oh, and it only does it when WARM, not cold, though that also may be a product not of temp but of the slightly higher warmup idle.

 

OK, checked the TPS today and I got .556v at the signal wire (center wire, right had 5.07v and left was ground). I can't find anywhere on the TPS that would allow me to rotate it - no rivets, vulcanized plastic tabs, barely even a seam. How do you rotate it? Once you do is it held securely in place?

Thanks,
Darel

 

you need to drill out the mounting holes so that the sensor has some play in it to move the TPS before you tighten it back up. the mounting holes might have a brass insert in it that you will remove...

edit: I'll bet that once it's set to the .7~.75v your throttle response will be much improved. I'd like to hear back to see if your (I think it was you) pinging issue goes away.

 

Got it, will report back later this week.

 

Well, I finally got around to playing with the TPS today. I drilled out the holes enough to get to .68v, but when I rotated it to increse the voltage the idle went up and started surging about 100 rpm. The knock went away, but perhaps only because of the higher idle, and frankly the surging was worse than the knock so I just turned it back to where it was and left it. Thoughts?