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auto kick down vers tappet noise ?

B

browneee

NAXJA Forum User
Location
Perth, Australia
Ok, I've got a 94 XJ sport ...

Now every time I put the engine underload (overtaking, accellerating uphill etc) the tappet noise become audible when in "drive". If I drop it down a gear into "3" it goes away. Now I've gone through my service manual and it reconmends checking the "kickdown", which I did and followed the adjustment method...

Have any of you made these adjustments &/or cured this problem ?
 
browneee said:
Ok, I've got a 94 XJ sport ...

Now every time I put the engine underload (overtaking, accellerating uphill etc) the tappet noise become audible when in "drive". If I drop it down a gear into "3" it goes away. Now I've gone through my service manual and it reconmends checking the "kickdown", which I did and followed the adjustment method...

Have any of you made these adjustments &/or cured this problem ?
Click to expand...
That don't sound like tappet noise, that sounds like detonation or spark knock.
Try better fuel and pull your engine codes, one of your sensors is off causing a lean air/fuel mixture.
 
Spark knock, ping, predetonation are all the same thing. They are caused by a too-advanced spark, a lean fuel mixture, or too low an octane rating for your fuel. It typically shows up a mid-RPM under load, such as while climbing a long hill. In my experience, most engines will ping a little under these conditions. A little ping is harmless, but heavy pinging can be dangerous to an engine. Higher octane fuel would be the first route I would take to solve the problem. If that doesn't do it, start checking sensors.

Jared:patriot:
 
I would check your knock sensor. Modern computer controled engines like yours shouldn't have any detonation (never a good thing) issues. It's basically just a microphone that'll pick up the "pinging" and tell the computer to make timing and/or fuel adjustments...........Hans
 
Oatmeal said:
I would check your knock sensor. Modern computer controled engines like yours shouldn't have any detonation (never a good thing) issues. It's basically just a microphone that'll pick up the "pinging" and tell the computer to make timing and/or fuel adjustments...........Hans
Click to expand...
What year did they quit using knock sensors? The newer ones don't have one.
 
Renix had them, HO didn't.
 
langer1 said:
What year did they quit using knock sensors? The newer ones don't have one.
Click to expand...
Ok, I stand corrected. After further research I found that '90 ('91 being the introduction of the H.O.) was the last year for knock sensors. I'm still learning about these things (just bought a '96) so, have patience with me.........Hans
 
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