Tach wiring help

[dliverance]

Hi gang. So today's project is getting my tach and speedo to work. I have already figured out the speedo (broken cable) but I'm stuck on the tach.

My cluster looks to have been added later on judging by the yellow writing that says 88 festiva. In the back of the cluster there was a wire added to the terminal that says IGN. Now, I'm not sure if that was for the tach but I'm assuming it is. In the bay, that same wire was just hanging loosely. Now, I see a connector on the coil that looks like the wire came out of the crimp but it's on the negative pole. I'm going to try to connect my wire to that and see if that gets it to work but i was wondering if anyone had some info on where the tach signal for the cluster comes from. My manual says ignition but I don't have it handy at the moment. The car is an 89 carby btw. Thanks in advance.

[TominMO]

I'd hold off on connecting that wire to the neg side on the col, until you get some advice from here. IIRC that wire should go to the + side of the coil. How about a pic of the back of your cluster? It's a non-tach cluster, right?

On an 88 wiring harness, that probably didn't have a wire built into the harness for a tach, I would expect the wire to go from the + side of the coil to the separate aftermarket tach itself. But if you have a tach cluster, then yes it would go to the tach in the cluster; probably the IGN location.

[dliverance]

It is a tach cluster. I found another thread that says it's supposed to go to the neg of the coil but I haven't hooked it up yet.

[TominMO]

Yeah, i found two threads where different people (FB71 is very knowledgeable) said run it from the neg side of the coil. So I now think it's safe to go ahead and do that. Let us know.

[dliverance]

So I ran the wire from the ign spot on the back of the cluster to the negative on the coil and still nothing. I think the cluster must be out.

[FestYboy]

Green wire to negative pole of coil. The harness should already be wired for a tach cluster. I'll verify when I get home in about an hour.

[dliverance]

Oh thank you. I would greatly appreciate that. I think I know which pin it is for the tach but I don't see a wire there in my harness

[bravekozak]

The Yellow/Green stripe wire from the back of the cluster goes to the negative side of the coil. In order for the tach to work, the ground must also be present.

[FestYboy]

^^^ Confirmed. Yellow wire green stripe.

[dliverance]

Mine doesn't have a yellow wire with a green stripe

[dliverance]

[FestYboy]

Is there a yellow/green on the firewall?

[dliverance]

I didn't get a chance to work on the car today. Was hiking with the gf. Will check in the morning.

[dliverance]

I'm not sure what you meant by on the firewall but I didn't see one. Yesterday the tach needle dropped down to the gas gauge. Going to open it up this weekend.

[TominMO]

I thought the 88 and 89 carbys didn't have the tach wire built into the harness. So you would need to run a separate wire from the coil negative side to the tach ign on the cluster. I would think the cluster plugs would take care of the ground for the tach; but maybe not for the 80s cars, and the tach function needs to be grounded separately as well. You should be able to easily accomplish this, if needed, by running a short black wire (black just to indicate a ground) from the tach ground on the back of the cluster to any other ground on there.