The Ford Torino Page Homepage
Forum Home Forum Home > Model Specific Forum > 1972-1976 Ford and Mercury
  New Posts New Posts RSS Feed - Factory Tach Hookup
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

Factory Tach Hookup

 Post Reply Post Reply
Author
Message
EAlonso761 View Drop Down
New Member
New Member


Joined: 08-April-2019
Location: California
Status: Offline
Points: 2
Post Options Post Options   Thanks (0) Thanks(0)   Quote EAlonso761 Quote  Post ReplyReply Direct Link To This Post Topic: Factory Tach Hookup
    Posted: 09-April-2019 at 1:03PM
Need wiring diagram for factory tach 1972 Ranchero. I have Fast Fuel Injection and E6 CD Ignition with E-92 coil. The factory tach usually would hook up to the positive side of coil.
Back to Top
EAlonso761 View Drop Down
New Member
New Member


Joined: 08-April-2019
Location: California
Status: Offline
Points: 2
Post Options Post Options   Thanks (0) Thanks(0)   Quote EAlonso761 Quote  Post ReplyReply Direct Link To This Post Posted: 09-April-2019 at 1:06PM
Need help wiring with CD Ignition and Fuel Injection
Back to Top
californiajohnny View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 05-October-2013
Location: winlock, wa
Status: Offline
Points: 14606
Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 09-April-2019 at 4:17PM
JOHN
74 GRAN TORINO S&H CLONE
74 VETTE CUSTOM
90 S10 BLAZER 4X4 LIFTED
77 CELICA CUSTOM
75 V8 MONZA SUPERCHARGED
79 COURIER VERT. SLAMMED
75 VEGA V6 5 SPD
70 CHEV C10 P/U
68 MUSTANG FB CONVERSION
Back to Top
californiajohnny View Drop Down
Moderator Group
Moderator Group
Avatar

Joined: 05-October-2013
Location: winlock, wa
Status: Offline
Points: 14606
Post Options Post Options   Thanks (0) Thanks(0)   Quote californiajohnny Quote  Post ReplyReply Direct Link To This Post Posted: 09-April-2019 at 4:22PM
that's the factory tach wiring now if youre using an MSD box or something like it, you may need to wire it differently... there is some discussion about that on here somewhere....
 i know todd and scott posted about that somewhere, search "tach no worky worky"???
JOHN
74 GRAN TORINO S&H CLONE
74 VETTE CUSTOM
90 S10 BLAZER 4X4 LIFTED
77 CELICA CUSTOM
75 V8 MONZA SUPERCHARGED
79 COURIER VERT. SLAMMED
75 VEGA V6 5 SPD
70 CHEV C10 P/U
68 MUSTANG FB CONVERSION
Back to Top
Rockatansky View Drop Down
Senior Member
Senior Member


Joined: 30-July-2010
Location: On The Road
Status: Offline
Points: 6059
Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 10-April-2019 at 10:04AM
IIRC 1972 uses the 2 wire system that powers the coil through the tach in series, not just hooked up to and taking siganl from the coil.

the later 3 wire tach is the one you want, same wiring as aftermarket reading coil signal

72 GT Ute
   
Back to Top
72FordGTS View Drop Down
Admin Group
Admin Group
Avatar
GTS.org Admin

Joined: 06-September-2005
Location: Ontario, Canada
Status: Offline
Points: 5802
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 10-April-2019 at 10:24AM
Like the wiring diagram shows and the other guys mention, the 1972 Tachs are current sensing.   They get the reduced voltage after the resistor wire, which means they were never desiged to even handle a full 12 volts.  Pretty much any aftermarket ignition is going to want a full 12 volts, not the 8 volts the resistor wire will give and the Tach requires.  Some CD igntions, like MSD, offer kits to make a current sensing tach work, but I have heard mixed results. 
 
So long story short, you best and easiest solution is to send the Tach to Rocket Man and have it converted to a voltage sensing tach that will read from the negative side of the coil.  That way you can run it with any ignition without worries.  
 


Edited by 72FordGTS - 10-April-2019 at 1:07PM
Vince

1972 Ford GTS Sportsroof - Survivor, One Family car

GTS.org Admin
Back to Top
Rockatansky View Drop Down
Senior Member
Senior Member


Joined: 30-July-2010
Location: On The Road
Status: Offline
Points: 6059
Post Options Post Options   Thanks (0) Thanks(0)   Quote Rockatansky Quote  Post ReplyReply Direct Link To This Post Posted: 10-April-2019 at 11:26AM
looks like the factory 3 wire tach started mid 1976?

you could just swap it out if you don't mind the font mismatch or get gauge overlays

i wonder if the faces can be swapped?

72 GT Ute
   
Back to Top
72FordGTS View Drop Down
Admin Group
Admin Group
Avatar
GTS.org Admin

Joined: 06-September-2005
Location: Ontario, Canada
Status: Offline
Points: 5802
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72FordGTS Quote  Post ReplyReply Direct Link To This Post Posted: 10-April-2019 at 1:05PM
Originally posted by Rockatansky Rockatansky wrote:

looks like the factory 3 wire tach started mid 1976?

you could just swap it out if you don't mind the font mismatch or get gauge overlays

i wonder if the faces can be swapped?

Yes, that is another and probably cheaper option.  You'd just have to hunt one down.
Vince

1972 Ford GTS Sportsroof - Survivor, One Family car

GTS.org Admin
Back to Top
DaleR09 View Drop Down
New Member
New Member
Avatar

Joined: 23-July-2016
Location: Enumclaw, WA
Status: Offline
Points: 31
Post Options Post Options   Thanks (0) Thanks(0)   Quote DaleR09 Quote  Post ReplyReply Direct Link To This Post Posted: 20-April-2019 at 5:04AM
I'm using an MSD 6A Ignition box on my 72 Ranchero GT , and used the MSD Tach Adapter for the factory tach to work. Works just great, fairly easy to wire in.
'72 Ranchero GT Q code (Sold)
'63 F100 Unibody CV swap
'03 Ranger 4X4 Stepside
'03 F350
'14 Fusion AWD Titanium
Back to Top
72GTS351CJ View Drop Down
Senior Member
Senior Member
Avatar

Joined: 30-November-2010
Location: NY
Status: Offline
Points: 1481
Post Options Post Options   Thanks (0) Thanks(0)   Quote 72GTS351CJ Quote  Post ReplyReply Direct Link To This Post Posted: 20-April-2019 at 7:38AM
Dale do you have a part # for that by any chance
72GTS Clint Eastwood Special                                     
Back to Top
DaleR09 View Drop Down
New Member
New Member
Avatar

Joined: 23-July-2016
Location: Enumclaw, WA
Status: Offline
Points: 31
Post Options Post Options   Thanks (0) Thanks(0)   Quote DaleR09 Quote  Post ReplyReply Direct Link To This Post Posted: 27-April-2019 at 4:51AM
part # 8920. 
'72 Ranchero GT Q code (Sold)
'63 F100 Unibody CV swap
'03 Ranger 4X4 Stepside
'03 F350
'14 Fusion AWD Titanium
Back to Top
DaleR09 View Drop Down
New Member
New Member
Avatar

Joined: 23-July-2016
Location: Enumclaw, WA
Status: Offline
Points: 31
Post Options Post Options   Thanks (0) Thanks(0)   Quote DaleR09 Quote  Post ReplyReply Direct Link To This Post Posted: 27-April-2019 at 4:53AM
'72 Ranchero GT Q code (Sold)
'63 F100 Unibody CV swap
'03 Ranger 4X4 Stepside
'03 F350
'14 Fusion AWD Titanium
Back to Top
 Post Reply Post Reply

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.06
Copyright ©2001-2023 Web Wiz Ltd.

This page was generated in 0.094 seconds.