if you look at the charging system wiring diagram in the 87 manual it loos relatively straight forward, but looks are deceiving....
the actual path the power follows in a 1987 is truely derangedIt runs from the battery, all the way around the engine bay (across the front) back to the firewall grommet into the dash, then back out to the connector fot the '87 alternator harness across the engine to the alternator... seems kinda silly considering that the alternator and the battery ar barely a foot apart...
The 4.0 alternator harness is all of 20" long and essentially runs to the 12v pos
terminal on the starter relay.
On my truck I ran a seperate wire to the fuse block in the dash and didn't
bother running a heavy wire back, because I have a tach instrument cluster.
How did I make the tach work?
I just hooked it up to the tach lead on the EDIS module and it worked perfectly...
(Basically I didn't do shit other than follow the manual
where you went wrong would probably be in the field circuit wiring
WHICD alternator are you using? does it have a Plug for the output power and look basically like your '87 alternator, except for the way it mounts to the alternator?
OR does it have a threaded stud for the output and an internal fan?
Look closer at the manuals I don't have the manuals in front of me and I have a sinus infection that makes looking at printed pages actually painful
But if I looked it up and foud your error for you you wouldn't understand how things work the way you will if you find the issue yourself.
Just take a step back, get something to eat and approach it when you aren't frustrated
Frustration and missing things are symptoms of working too hard and letting your blood sugar drop.
Whenever you feel like throwing or smashing things get something to eat.
NOT something sugary that makes it worse later...
AD