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Technical => Electrical Tech => Topic started by: pro-five-oh on April 27, 2010, 11:24:35 AM

Title: What wires feed the tach on a 83-84 Turbo?
Post by: pro-five-oh on April 27, 2010, 11:24:35 AM
Hey all,

I am trying to get the tach working on a 1984 LTD LX, which uses the same cluster as a Turbo Coupe. The car was converted to a carb, and I assume all the CFI wires they cut made the tach die.

The car has an aftermarket tach on the steering column.  I plan on using its wiring to feed the stock tach.  Can anyone tell me which wires on the gauge cluster harness need the aftermarket tach's wiring to make it work again?

I have a 1984 LTD EVTM manual, but it doesn't cover the LX model. Hence my problem. :)
Title: What wires feed the tach on a 83-84 Turbo?
Post by: softtouch on April 27, 2010, 02:29:21 PM
84 T-Bird EVTM
Title: What wires feed the tach on a 83-84 Turbo?
Post by: pro-five-oh on April 27, 2010, 04:33:23 PM
YES, that's what I needed! 

:burnout:

YOU RULE!!!
Title: What wires feed the tach on a 83-84 Turbo?
Post by: blu84302 on August 09, 2010, 12:29:32 PM
This is almost what I need to know. I have a 4 cylinder TC cluster and I'm going to V8.  was yours a v8 cluster in the LTD?  Did you have to add a resistor to get the cluster to work or was it already setup for v8 being that it was from an LTD. 

It's cool that I found this EVTM.  Good looking out.
Title: What wires feed the tach on a 83-84 Turbo?
Post by: Chuck W on August 09, 2010, 01:16:40 PM
You can't just add a resistor on the wire from the coil, won't work that way.

You need to try and sort out what is the proper circuitry on the tach itself, and modify it there. 

I had 2 people looking at it, and neither was able to figure it out, or follow through.

I was originally looking at it when I swapped the 83-84TC cluster into the old 80 XR-7 I had.  Never was able to sort it out.
Title: What wires feed the tach on a 83-84 Turbo?
Post by: pro-five-oh on August 09, 2010, 01:50:06 PM
It isn't like the 87-88 TC tachs that only need a resistor change to work.  Yes the LTD is a V8 from the factory, you need that tach to make it work easily. That's hard to find, so I'd try getting the guts from a 79-86 Mustang tach instead and hoping that stuff can be switched out.

FWIW, I couldn't get the tach signal to work, since this car has been converted to 4BBL with an aftermarket dizzy.  Oh well, it's gonna turn back into a EFI car soon enough, so I'll wait until it changes under the hood again!
Title: What wires feed the tach on a 83-84 Turbo?
Post by: Chuck W on August 09, 2010, 02:11:34 PM
Quote from: pro-five-oh;331282
It isn't like the 87-88 TC tachs that only need a resistor change to work.  Yes the LTD is a V8 from the factory, you need that tach to make it work easily. That's hard to find, so I'd try getting the guts from a 79-86 Mustang tach instead and hoping that stuff can be switched out.

FWIW, I couldn't get the tach signal to work, since this car has been converted to 4BBL with an aftermarket dizzy.  Oh well, it's gonna turn back into a EFI car soon enough, so I'll wait until it changes under the hood again!


Odd you couldn't get it to work.  On the 80, which was still carbed, I just ran a wire from the neg side of the coil, to the tach input on the cluster.  It worked, just read wrong due to the fact that it was a 4cyl tach on an 8cyl engine.  No other magic involved.
Title: What wires feed the tach on a 83-84 Turbo?
Post by: blu84302 on August 09, 2010, 02:46:44 PM
Thanks guy's.  Check out my build thread.  I made something for the 84 TC cluster to V8 Tach.
Title: What wires feed the tach on a 83-84 Turbo?
Post by: pro-five-oh on August 09, 2010, 03:00:04 PM
Quote from: Chuck W;331287
Odd you couldn't get it to work.  On the 80, which was still carbed, I just ran a wire from the neg side of the coil, to the tach input on the cluster.  It worked, just read wrong due to the fact that it was a 4cyl tach on an 8cyl engine.  No other magic involved.

The tach signal they used when they switched over wasn't compatible with the stock tach.  The car is a mess under the hood, so to speak. Supposedly MSD makes a conversion kit (of some sort) to make it work.  Whatever, it's gonna get converted to FAST sooner or later.