wtf...mallory 685, shift light issues,tach issues
Electricity always goes to the path of least resistance. I doubt your box is bad, but I would double check your wiring. If you have a schematic for your box I would make sure the tach signal circuit doesn't corrupt there. Does that box have a v6-v8 switch?
Thread Starter
TECH Veteran
iTrader: (246)
Joined: Mar 2008
Posts: 4,984
Likes: 1
From: Chicago/Crown point
nope just v8 and i read somewhere else that peeps were having the same issue where the pcm was disrupting the box and not allowing the tach to work properly but there was no solution.
Thread Starter
TECH Veteran
iTrader: (246)
Joined: Mar 2008
Posts: 4,984
Likes: 1
From: Chicago/Crown point
yes its the digital box....but to tach check, all you do is set what you want as your rev limit then turn the key off and back on real quick, it will then show setting 1. After that your good to go, the box now recognizes the tach signal.
This is weird only cuz I have installed this dozens of times on carb'd setups and no problems now when i go to install on Lt1 car i have an issue, what makes it worse is that its a sidejob!
This is weird only cuz I have installed this dozens of times on carb'd setups and no problems now when i go to install on Lt1 car i have an issue, what makes it worse is that its a sidejob!
Ok, if I am understanding you right, you spliced into the back of your PCM for the Tach signal?
Why did you do this and what did you hook it up to?
If you use the tach output on the box you shouldn't have to splice into the Tach lead coming out of your PCM. Since the Mallory is plugged into your coil and is essentially running you ignition, THAT is where you get your tach signal from. There is no need to splice into your PCM.
But maybe I'm just misinterpreting you.
Why did you do this and what did you hook it up to?
If you use the tach output on the box you shouldn't have to splice into the Tach lead coming out of your PCM. Since the Mallory is plugged into your coil and is essentially running you ignition, THAT is where you get your tach signal from. There is no need to splice into your PCM.
But maybe I'm just misinterpreting you.
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
