hooking up tach 1st gen

[1988s1017522]

am i able to run off the wires from stereo for ground and what not seems to be easiest way to do it but im not sure how to get light on it tried on orange wire for illumination nothing happened anyone point me in right direction

[neo71665]

Try running the wire to the light switch, get a test light and find a wire that is hot in the light (parking light if you want it on with the rest of the gauges) on position.

[1988s1017522]

wow gonna be pita running wires alone haha can the other wires be hooked yp to radio as well

[93v6banger]

those 2 wires to the fuse box for power and light, 1 wire to the coil and a ground to an already existing ground under the hood.

[1988s1017522]

everything is hooked yp to stereo wires and green wire to white wire under dash safe to keep like that?

[neo71665]

Its fine to wire everything under the dash, its how I do all my s-series installs. I've never figured out why anybody would want to run any tach wires to under the hood when everything you need is already in the cab.

[1988s1017522]

i mean i got mine hooked right up to the stereo wires behind radio uis that ok?

[The_Raven]

Quote: Originally Posted by neo71665

Its fine to wire everything under the dash, its how I do all my s-series installs. I've never figured out why anybody would want to run any tach wires to under the hood when everything you need is already in the cab.

Tach wire isn't always ran into the cab. It's only the factory tach equipped trucks that I've seen with a tach wire inside the cab. EFI equipped trucks are kinda the exception. Ther eare a couple wires at the ECM that will act like tach wires, though, these signals at the ECM may or may not be stong enough for some aftermarket tachs.

I would never connect the tach (powe) wires to the audio system wires, mostly because the accessory wire that feeds the radio is dead during crank, and feel that the tach should be on when ever true ignition is on, and if the tach has poor filtering, you could end up with an "audible tachometer" through the sound system.

Best to connect the ignition wire to the ignition switch, the illumination wire to the head light switch (dimming circuit), the ground I usually attach to the kick panel, steering column support or some other hidden away solid piece of metal with a good ground reference, people say it should be grounded to the engine, but I haven't seen any difference in tach function in doing so. The tach wire should be connected to the coil negative wire directly. Like I said before you can find a couple wires at the ECM that act like tach wires, but they can be too weak to drive the tach properly sometimes.

[neo71665]

Never installed a tach on anything older than a 86 but every one 86 and up has had a tach sigal on the ECM (with or without factory tach) and I've never had problems using it. I can pull out the factory wireing diagrams I have for my 87 and give you the wire color and pin out if need.

[The_Raven]

Quote: Originally Posted by neo71665

Never installed a tach on anything older than a 86 but every one 86 and up has had a tach sigal on the ECM (with or without factory tach) and I've never had problems using it. I can pull out the factory wireing diagrams I have for my 87 and give you the wire color and pin out if need.

Don't worry I know the wire colours, I just know that not every tach is happy with using those signals.

The colours are purple/white ("Ref hi") and White ( "Ref lo"), the purple/white is the RPM ref or "pulse ref" and the white is the signal back to the ICM to control timing.

[1988s1017522]

well its hooked up to stereo wires everything seems fine ran green wire from tach to under dash wiring harness white wire should be ok leaving it the way it is or not?

[1988s1017522]

anyone know what reline is for 88 2.8 automatic so can set tach?

[1988s1017522]

redline*

[ericknight]

http://cgi.ebay.com/ebaymotors/1982-...=p4506.c0.m245

Looks like 5500 on the factory tach.

[bmxzach]

if i buy a tach off summit racing, i can hook it up without much trouble? i have an 87 2.5L 4spd. possibly 5spd swap. (i own the tranny)

also, a full instruction list would be greatly appreciated. haven't decided on a tach yet so a link to something affordable i can mount on the dash would also be appreciated. i know nothing about trucks, just starting to learn. like i said, any help would be appreciated. thanks!

[1988s1017522]

go to pep boys or advance auto or auto zone or parts store sunpro is good tachs fairly cheap as well

[bmxzach]

i live in ontario

[1988s1017522]

well im sure ya got some type of parts store there that carries sunpro or some other brand eh

[scott9001]

Quote: Originally Posted by bmxzach

i live in ontario

go to ideal suppy they can order you in some nice autometer gauges napa store pretty much the same thing. where in ontario are you

[bmxzach]

kitchener area. i'm thinking of waiting and redoing my entire cluster at once with a nice gauge set.

[scott9001]

kitchner im in mitchell lil west of stratford i got a tach il sell ya

[bmxzach]

details?