Aftermarket Tach, 4.0

[Hahnsb2]

I have a tach dash, my 1st gen tach doesn't play nice with the 4.0 because of the EDIS and waste spark (or so I'm told), will this also be a problem with aftermarket tachs? I'm not swaping in a 2nd gen dash, I much prefer my 1st gen and I've already done all my wiring.

 

[Twizzler09]

Just splice the aftermarket tach into the Tach Input wire off the PCM. For a '94 4.0 it should be Tan w/Yellow stripe, pin 2 I think. Dont quote me on the pin number, lol.

Just wiring it into the Tach input wont hurt anything, Theres lots of people on RPS that have done the same thing without a problem. It "should" give a correct RPM readout, also.

Thats the easiest way to wire in a Tach without creating a huge headache for yourself. Equus makes Tachs specifically designed for DIS or Coil on Wire ignition, but they're slightly more expensive, and a bit more complicated.

 

[Hahnsb2]

Does it matter if I hook the wire on the tan/yellow wire under the hood instead of at the PCM? I have my original tach hooked to the wire under the hood right now and it works but it reads way high. I have Equus oil pressure and temp gauges that I really like, I don't care for their tachs though, I hate how the number scale starts in the 5 o'clock posistion.

 

[Hahnsb2]

Bump

 

[Twizzler09]

The Tan/yellow under the hood should be alright too, as far as I'm aware the signal should be precisely the same.

I have an equus tach in mine, and its "readout" starts in like the 7 o'clock position, check it out:

I also cleaned up the install since I took those.... the wires are hidden alot better, that velcro strip I had on the column for testing purposes is gone too....now I just gotta paint the hose clamp black to blend it in and voila! haha

I accidentaly had the dash lights dimmed in the second pic, its actually a decent bit brighter than that, haha.