Thread: Need a cheap tach fix

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installed a chevy V8, HEI ignition in a 90 Jeep wrangler that originally had a 4 banger.
I hooked up the tack and it works - but it reads twice teh real RPM (seeing 8 coil pulses when it expects 4 per tach revolution).

Anyone know of a cheap fix for this? I found a website selling a black box that allows you to hook any engine to any tach for $80. I was hoping for a backyard fix...

Any ideas?

Better to be pissed off than pissed - unless you like that sort of thing

Divide in half works, but the tach numbers don't go high enough.
not sure if there is a switch - a 4 or 6 was avaliable. some cars you can change a resisitor on the tach...but ya gotta know what to do, so i may bte first to try and figger it out.

I am fighting the front axle lock vac system at teh moment - the lines are the hared plastic ones and broken, color coded even, and hooking them up correctly does not make things work as 'designed'. Besides, someone stripped off the indicator switch to turn on the 4WD light anyway. A cable deal is available that replces teh vac system, making it totally manual - bt it costs a whopping $200! I'll run vac lines to the dash and just tee tha damn things before i spend $200!

My brothers '90 Ford Ranger had the same problem cept' his would get stuck in between and the gears would grind for 50' or so before it came out of 4X4.