Tapping noise
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Senior User
Joined: Oct 2001
Posts: 131
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From: Millersville USA
Tapping noise
I have a EFI 460, and it seems to wanna tap above 2000 RPM, especially on the highway doing about 50 mph. It doesn't do it at lower speeds and rpms. What could be causing this?
Moderator
Joined: Dec 2001
Posts: 22,436
Likes: 17
From: Louisville,Ky.
Tapping noise
Does it do it under a load?( accelerating) It could be spark knock which is caused by a lean fuel mixture or too much ignition timing. Before you adjust anything, try a tank of 93 octane fuel and see if it goes away. If it does, then back the timing off 2 degrees at a time until it goes away when running 87 octane. If the premium fuel doesn't cure it, the check the EGR valve, It could be opening too far or not shutting completely.
