1986 F150 4.9 Duraspark II - Factory Guage Wiring Help

[Newusr]

Can anyone steer me in the right direction as to what wires to splice or use for the factory guage to work.

1986 F150 Duraspark II conversion

Wiring from late 70s Ford truck.

Tachometer
Oil Pressure
Temperature Sensor
Voltage

I have the single terminal temp sensor installed.

[Gary Lewis]

I may be able to help, but need a bit more info.  Do you mean "gauges" instead of "gauge"?  If so, then you need to wire it as shown below.

Those schematics are from here: Documentation/Electrical/1985 EVTM.  I chose that one instead of the 1986 EVTM because you said that your wiring is from the 70's.  In 1986 Ford changed the wire colors ever so slightly by dropping the hash marks and dash marks, but one thing Ford was good about - they didn't change the basic wire colors over the decades.

However, one thing that did change through the Bullnose years is the fuel system wiring.  So as you get into this you will need to confirm how your fuel system is set up.  The one shown in the top schematic is the simple one and the one I think your truck will have.  But we may need to discuss that.

[Newusr]

For the tach. I'm sorry I am pretty sure this has been asked before...

Which of the two wires do I use and do I just leave the other one taped up?

DG/Y or BK/LG

[Newusr]

For the record, all the guages except the tachometer are working and hooked up now.

[Gary Lewis]

Glad you have everything else working.

On the wires, if you'll look at the schematic on Page 27 closely you'll see that the Bk/LG says 8 CYL ONLY.  That's a ground and it tells the tach to go into 8 cylinder mode.  But with a 6 you don't want to connect that.

Here's a snippet of Page 27 marked up from our page at Documentation/Electrical/Tachometers that may help:




But you do need DG/Y as it is the trigger to the tach from the ignition.  As for where it goes, this picture from the same page may help.  You want the terminal marked SIG.  But some tachs have a plastic cover over them and don't have the same labels showing.  However the layout is the same on all tachs, so you want the one in the upper left when viewed from the rear.