Electrical Stock tach wont work plugged into msd6al box?

Smurfstang88

Member
Nov 11, 2019
15
2
13
18
Virginia
Still dont see what the reason is as to why the stock gauge wont work hooked up to the negative side of the coil.. as for the needing a tach adapter to plug into the msd tach output and read accurate i dont see why considering on msd’s site they say you need the adapter if you have a multiple coil application which i dont so?? Id love to actually have some actual information as to why it doesnt work. Is it because its a 4cyl tach or because i need a tach adapter and why? And does this mean even with a v8 cluster id still need an adapter? Id think i could have gotten a definitive answer on this by now from one of you guys
 
  • Sponsors(?)


jrichker

StangNet's favorite TOOL
SN Certified Technician
Mar 10, 2000
27,213
2,727
234
74
Dublin GA
lowendmac.com
Still dont see what the reason is as to why the stock gauge wont work hooked up to the negative side of the coil.. as for the needing a tach adapter to plug into the msd tach output and read accurate i dont see why considering on msd’s site they say you need the adapter if you have a multiple coil application which i dont so?? Id love to actually have some actual information as to why it doesnt work. Is it because its a 4cyl tach or because i need a tach adapter and why? And does this mean even with a v8 cluster id still need an adapter? Id think i could have gotten a definitive answer on this by now from one of you guys.
If you would have gone to the Holley/MSD website and learned what MSD means, you would have had your answer...

MSD=Multiple Spark Discharge. With a stock engine and a MSD there are multiple sparks for each cylinder each time it fires. There is a RPM at which it switches from multiple sparks when the spark plug fires on the power stroke to a single spark. The multiple spark confuses the tach circuitry, that is why you need the adapter.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
14,947
4,723
193
polk county florida
the four cyl tach is not compatible to a V8. If you think about it then it would make sence. There is a way to make it work by adding a resister.
there is also a tech thread on the 4 cyl to V8 swap here.
just a quick google search would have all the answers for you instead you choose to get your feathers all ruffled because you think we should have given you the answers that a small amount of time in search mode would've resolved.
We don't mind helping you out and that is what this site is for but we charge extra for instant answers and the price doubles when they are correct. :jester:
 

Blown88GT

Founding Member
Nov 13, 1999
1,825
376
124
Palm Beach Gardens, FL
UPDATE
So i tried stock wiring today and no surprise to me it did not work.. tach moves slightly when i turn the ignition on so its getting power, but does not read anything when engine is running.. im assuming either because its the 4cyl tach like mentioned or msd ignition aforementioned..

Edit: So looks like either I’ll be waiting to find a stoch v8 cluster, or possibly a external tach as it seems theres no other options unfortunately.
Wiring is the same, tachometer is different.
EVTM_p021.jpg