Recently after getting my car put back together I have noticed that my speedometer and tach are not working correctly. My speedometer stays at zero when I am driving but when I am at a light and begin to accelrate it jumps from 0 to 100 then back to 0. Another problem has to do with my stock tach reading half what it should be reading. For example at idle it reads 500rpm. My FAST system was reading that I was getting 12.7 volts to the computer. I thought for some reason I had a bad alternator so I went out and bought a 220 amp with no luck. This problems started after the following mods:

-Installed 9-in (disabled ABS)
-Installed LTCC box
-Removed MSD 6BTM


The funny thing about the situation is that I have a Monster tach in my car that reads the correct rpm. I would use a scanner to scan for coded but unfortunately I can not because I am using a FAST system. Any help would be greatly appreciated. Thanks in advance.

 

TTT, Anyone have any ideas.

 

TTT