Knock

[Jonesy]

Had a few problems after a 3 hour drive to inverness at the weekend the car was running fine before. On start up the knock levels can read as high as 70, then drop to 0 then back to 70, but as soon as i pull away under load the knock levels drop normally back to zero or max 15 depending on how hot it is outside, but always drops to zero when driving hard.
Any idea's whats causing this or could it just be a faulty sensor, also at what knock level is it worth worrying about.
Also the car used to idle smoothly between 1300 - 1500, but now idles about 900, which would be ok but it sounds quite lumpy.
Any help appreciated

 

[Jonesy]

The car is overfuelling quite badly, think this is my idle problem and also doesnt pick up as well as it used when you put he foot down, and alot worse on fuel.
There's another post about my SAFC possibly causing the car to run rich, but i think this is also a seperate problem, because the car ran fine for a couple of months with both the chip and SAFC, this has just happened recenlty.
I have read a few posts about re earthing the MAF sensor do you think this could be my problem.

 

[sadsy]

ive had a similar problem with the SAFC2, ive just put it down to hot days (weather) because it ONLY does it then, and when you put throttle down it goes to zero. mine idles at 900 to 950 though.

 

[Fusion Ed]

Goes to show how meaningless these things really are. There is NO way the engine is knocking on idle. Knock sensors are typically quite unreliable more often than not, especially on simple devices like this.

 

[Jonesy]

Ok cheers i take it knock only occurs on load. What about over fueling could that be the maf sensor needing re-earthed.

 

[Jonesy]

Think i've got this sorted there was a lot moisture built up on the dizzy cap. Certainly running and idle'ing a lot smoother, would this also tie in with the car over fueling.