Crazy Rev counter.

[Waspy]

So, today I changed the water pump and rocker cover gasket.

Now the rev counter sits at 7000 when idling, when I drive it stays still sometimes and others I'll will drop further to point at the fuel gauge (!) and others bounce up (down?) to 3-5k... Any ideas on what could be causing it, or anyone experienced it before? I disconnected the batter for 3 secs when off and the needle dropped back to zero. But when I turned it back on it jumped back to 7000 and stays there even when off.

Cheers guys.

[Gambit]

Check earth strap from behind the coil

[Waspy]

Check earth strap from behind the coil

Yep. Thanks, the earth was all covered in oil and crap, cleaned it up and good as gold again

[Superspecs]

I'm having this same problem too, I'm a bit of an electrics noob though. Can you explain how to check the earth strap?

[Waspy]

Mine was earthed to the rocker cover. It should be a metal tab with wires attached to it. Mine was attached to the far back right bolt. Give it a clean, put it back on and see if it makes any difference.

[Thom89]

I'm having this same problem too, I'm a bit of an electrics noob though. Can you explain how to check the earth strap?

Earth straps generally are heavy duty wires that connect the battery to the body/engine, both ends of the wire must be attached to their locating points, these connecting points must be clean, and free of rust to work properly, poor earthing can cause all sorts of electrical gremlins!  Earth straps can also be found on the engine block to the body, and also gearbox to body.... so when someone says "check all the earth straps" you need to identify where they are, have they been disturbed for any reason, and are they in good serviceable condition, clean and tight

Thom

[Superspecs]

Thanks for all the help guys.

That's interesting actually as I have recently changed the battery, maybe I have disturbed something.

[Sgt_Lemon]

Three posts in a row about rev counters.

[Superspecs]

Hi all,

I tried the trick of removing fuse 21 and replacing it and despite my skepticism it actually worked. All systems are now working including the MFA.

Im so chuffed! Thanks for all the help.