aftermarket tach

[gold84gmc]

hi, i have an 84 gmc 2500 2wd with the 5.7L 4bbl engine...im trying to hook up an aftermarket tach. it says to hook up one of the wires of the tach to the distributor, on the connection marked "tach". but i looked and there is already a white wire plugged into there but the truck dosnt have a factory tach. so can i unplug that wire and plug in the one for the tach? or will it screw up something or what? and does anyone know what that white wire is for or where it goes? thanks.

[gold84gmc]

anyone have any ideas? or should i just try it.

[Lt.Del]

I am assuming you have an HEI distributor.  Your white wire is not in the "Tach" slot, it is in the "coil" slot.  The green wire from the tach goes to the terminal labeled "tach" on distr.cap. 

If you ever replaced the coil inside the distr. cap, you'll see what I'm speaking of. If memory serves me, you will see a red wire and a white wire from the coil.  The only wire you see plugged into the bottom side of that area is the red wire w/ white clip.  That is the ignition wire.

[DirtyLittleSecret]

And if the wires are pink/purple with a light lemon twist and sugared rim? (just jokin')

[123 pugsy]

 

hi, i have an 84 gmc 2500 2wd with the 5.7L 4bbl engine...im trying to hook up an aftermarket tach. it says to hook up one of the wires of the tach to the distributor, on the connection marked "tach". but i looked and there is already a white wire plugged into there but the truck dosnt have a factory tach. so can i unplug that wire and plug in the one for the tach? or will it screw up something or what? and does anyone know what that white wire is for or where it goes? thanks.

Pull it out and try it.

[VileZambonie]

Do you have Vacuum advance or HEI with ESC?

[gold84gmc]

here is some pics of what im talkin about. the white wire that plugs in to the "tach" slot

[gold84gmc]

as far as i know its vacum, because its a 1984

[VileZambonie]

Is there a 4 wire plug connected to the distributor?

[gold84gmc]

yea there is one big plug, not sure if its 3 or 4 wires though..i'd have to look.

[VileZambonie]

Then you need that wire. Just splice into it.

[gold84gmc]

alright, thanks