10 replies to this topic

[Ryan n Angela]

Mornin all

 

As above got a bizarre fault on my rev counter. Its a Smiths 80mm job and basically its reading about 1000rpm below what the engine is actually running at. For example on tickover which was sitting between 900 and 1000rpm it registers 0! Engine is running fine but not even a twitch on the gauge. But then as you drive or rev the engine it works as normal but reading 1000rpm below so when at 1000rpm on the gauge the engine is running 2000rpm and on right through the range. Cant for the life of me work out why. Up to this point the gauge has worked perfectly. 

 

Wiring in is clean and all connections tight and the same at the coil etc.

 

Anyone got any ideas/suggestions???

 

Cheers

[Bungle]

is there a switch on the back for number of cylinders the engine has ?

[RossKnight]

Are you running electric ignition? 

[tiger99]

"Are you running electric ignition?"

 

Well, unless he has reverted to 1900 technolgy with hot tube ignition, or has done a diesel conversion, I would expect so.

 

http://en.wikipedia....ot-tube_ignitor

 

But seriously, if he is running ELECTRONIC ignition, the tacho may not like the form of pulse that it is being fed, but most likely some component within the tacho has failed. It may be repairable by a specialist.

[Ryan n Angela]

is there a switch on the back for number of cylinders the engine has ?

Yes mate, not been touched. Set on 4

[RossKnight]

"Are you running electric ignition?"

 

Well, unless he has reverted to 1900 technolgy with hot tube ignition, or has done a diesel conversion, I would expect so.

 

http://en.wikipedia....ot-tube_ignitor

 

But seriously, if he is running ELECTRONIC ignition, the tacho may not like the form of pulse that it is being fed, but most likely some component within the tacho has failed. It may be repairable by a specialist.

Okay no worries, I won't both trying to help, even though I had similar problems before.

[Ryan n Angela]

Are you running electric ignition?

Hi, yes dude Electronic Ignition but has been since I bought her and the tacho was fine previously.

[Ryan n Angela]

"Are you running electric ignition?"
 
Well, unless he has reverted to 1900 technolgy with hot tube ignition, or has done a diesel conversion, I would expect so.
 
http://en.wikipedia....ot-tube_ignitor
 
But seriously, if he is running ELECTRONIC ignition, the tacho may not like the form of pulse that it is being fed, but most likely some component within the tacho has failed. It may be repairable by a specialist.

Okay no worries, I won't both trying to help, even though I had similar problems before.

Hang on! I was me that needs the help not tiger!!! I was though starting to think it was a fault in the gauge if you have any advice I would appreciate it dude.

[RossKnight]

Hang on! I was me that needs the help not tiger!!! I was though starting to think it was a fault in the gauge if you have any advice I would appreciate it dude.

 

 

Mine was over reading, and would sometimes jump from say 2k rpm to 3k rpm with no actual throttle change, I realized I had the ELECTRONIC module  wired into the original connection, which was only giving me 9v, and I just rewired it to a 12v supply and it worked fine. But of course if yours is already on a 12v supply, I don't know what to suggest.

[dklawson]

Which type of 80mm Smiths tach do you have?  Look around the face for the letters "RVI" or "RVC".  Let us know which type your tach is.

[Ryan n Angela]

Which type of 80mm Smiths tach do you have?  Look around the face for the letters "RVI" or "RVC".  Let us know which type your tach is.

I'll have a look this morning mate