How do I hook a rpm tach signal wire ( the green wire ) to a coil pack? It's a 3800 series 3.8L LE 1988 Pontiac bonneville

What tach . factory in the instrument custer , Aftermarket ? The tach signal comes from terminal E at the ignition control module and the wiring diagram for a 1988 pontiac bonneville 3.8 L is a white wire .

Aftermarket or factory tachometer? ignition coil pins A,B,C . B is white wire -this is tachometer signal to instrument cluster .

You probably have a bad coil , possibly ! Check out this video . It's a Oldsmobile but same ignition type ,just a four cylinder ! GM Ignition System diagnosis 1988 Olds Cutlass Pull the plug wires off of one coil at a time !

If 3800 engine the timing is 1-6-5-4-3-2
If 2.8L or 3.1L or 3.4L timing is 1-2-3-4-5-6

Coil packs on 3800 are (1 / 4, 5 / 2, 3 / 6)
Coil packs on 2.8L or 3.1L are (1 / 4, 6 / 3, 2 / 5) 1995 earlier across the front from right to left.
Coil packs on 3.4L are (5 / 2, 3 / 6, 4 / 1) 1996 across the back from right to left.

According to info found online, the wiring for a 1995 F series tach gauge is as follows;

Tach..........Tan/Yellow wire...........at coil connection.

Your truck does have a coil that feeds the distributor, correct?

Vehicle speed sensor. In the transmission by the passenger side CV shaft.

It is usually to the positive side of the coil - also depends on what type of distributor cap you have, if there is a 3-4 wire plug that goes to the cap, one of them should be marked TACH

Here is a diagram of the firing order for you 3800 engine. Cylinders 1 and 4 are misfiring because the operate under the same "Coil Pack" and the coil pack has unfortunately gone bad. O'Reilly sells them for between $30-50 depending on the amount of warranty coverage you want. To replace, simply unscrew the screws that hold the coil pack in place. WAIT before unplugging the plug wires. Place the old coil pack and new coil pack next to each other, unplug one plug wire, then plug it to that same port on the new coil pack. then do the same for the other plug wire. Then screw your new coil pack in place, and start you car. should run fine!

there will be a wire that goes to to power. then ground im sure you know that. also possibly a wire for your lighting. just splice that into the pwr wire coming off the dimmer. to get rpm's it should be a green wire coming off your tach connect it to the negative side of your coil pack.

try to conect it into the +positive battery terminal.