Topic: I need help with a 91' 4.3L tach installation.

[RockSlayer]

I bought my son a 1991 S-10 that we will eventually turn into a 4x4 crawler. It has a 4.3 with TBI. We were installing one of those big 5" tachs with a shift light, and I was wondering if anybody knows if there is a factory tach connector somewhere in the mess of wires? There is not a tach in the dash from the factory.

[Ferg]

Check at the local library.  You can look at wiring diagrams for free.

[79coyotefrg]

on the distributor  there  is a plug  on the side,  should be 1 thats empty, its for the tach

[RockSlayer [OP]]

on the distributor  there  is a plug  on the side,  should be 1 thats empty, its for the tach

That is where I was looking, just like on the HEI distributors, but this has the coil on the right side valve cover. No tach connection there either.

Check at the local library.  You can look at wiring diagrams for free.

Thanks for the idea, I forgot about the library. I'll give that a try.

[79coyotefrg]

hmm,  this has the muti coils??    all you need is 1 connection to 1 primary wire to 1 coil

[RockSlayer [OP]]

hmm,  this has the muti coils??    all you need is 1 connection to 1 primary wire to 1 coil

It looks like one coil, It's just mounted by the valve cover and has a coil wire that goes to the center connector on the Distributor cap, just like in the old days. It has 2 plugs going to it, both with a red and a white wire on each plug. the wire gauge is different for the 2 plugs. I'm going to poke around today after work. I'll see if I can just go old school and hook it up to the hot side of the coil. I was hoping for an easy / clean connection.

[FIREBALL]

Wish I could help. I used a Howell harness when I did my conversion and it had a wire stubbed out for for the tach and i'm not sure if their color would match the factory.
I checked my service manual for you, but couldn't find anything referancing the tach. Sorry.

[Tice]

It just so happens that I have a Haynes manual for a S-10, but......it does not mention anywhere in the whole book where to hook up a tach!!! Even the wire diagram of the instrument cluster doesn't have a factory tach. It does talk about hooking up a hand held tach for idle control on a carbed engine, but says to follow the manufacture's (tach) recomm :therethere:endation on where to hook it up. Sorry!

[RockSlayer [OP]]

I was thinking, maybe it is better I don't hook it up. He might think that 4.3 with 223,000 miles can turn 10,000 rpms.

[FIREBALL]

The rev limiter will keep him from doin that.

[Willy Mammoth]

The rev limiter will keep him from doin that.

And what do you think the rev limiter sees, RPM. There should be a connection at the brain for the tach. you need to get the manual for that year and search for it. I had no problem hooking mine up on a 93 4.3.

I suffer from CRS so I can't help with the details.

[RockSlayer [OP]]

i went old school with this tach install. I hooked it to the negative side of the coil. Foo-ee on the ecm signal crappolla. It works great. i set the shift light to 4500, and told him if he blows it, we can't rebuild it.