tach problem
Thread Starter
8th Gear
Joined: Mar 2008
Posts: 8
Likes: 0
tach problem
my tach is going the wrong way. he is running from 7000 rpm (idle)to 0 rpm (full throtle). where should i start looking. i have already a brandnew dash printed circuit installed
thanks
thanks
Last edited by arijs; Apr 26, 2009 at 10:26 AM.
Former Vendor
Joined: Apr 2009
Posts: 766
Likes: 3
From: Charlotte North Carolina 704-394-5150
Boy I thought I have heard and see it all. Possible the ground and power wire are switched or your board on the tach is burned out. I have seen tach's go from 0 to red line just by turning on the key WITHOUT the engine running.
Le Mans Master
Joined: Sep 2002
Posts: 5,236
Likes: 898
From: Myrtle Beach SC
Ok...you have options. I asked John Gardner who makes tach boards and has been a student of HEI for over a decade. Gardner states that you may need a new tach meter head. One or more of the three terminals on the meter is open and this can be checked by taking the circuit board off and check the resistance with an Ohm meter. Any way you connect the two leads you should read about 200 Ohms or 400 ohms. No reading indicates and open and bad tach head. This can be repaired by someone that knows what they are doing. Gardner makes these repairs.
My view of tach circuit boards is when they are bad, replace with a new one due to new components and better technology. Can't say that about the tach head though.
