Thread: HEI Tach wire

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My Tach stopped working the other day. It was still plugged into the HEI Cap but the wire broke off of what ever it's supposed to be connected to. I've looked around for another wire but can't find anything. Does the tach lead connect to something inside the distributor? I'm lost here... Any help?

This is what I'm talking about. I know it has to be something simple.

Originally posted by kschilling
This is what I'm talking about. I know it has to be something simple.

is it a after market tech or fact. tech?

It's a Factory Tach in the car. The HEI was added. 73 Z28s didn't come with them and I purchased the car with it already installed. I just can't figure out where the lead goes.

Originally posted by kschilling
My Tach stopped working the other day. It was still plugged into the HEI Cap but the wire broke off of what ever it's supposed to be connected to. I've looked around for another wire but can't find anything. Does the tach lead connect to something inside the distributor? I'm lost here... Any help?

in the 80s GM cars the tech had a condenser or some kind of choke device mounted on the fire wall between the dist. and tech. it looks like a condenser with a wire going in one end and coming out the other end.

There appears to be a "condensor looking thing" attached to the firewall with a brown wire coming out the over end. The brown wire then goes into the wiring harness. That might be it! Any clue what it's called? It appears to have "worn" thin and broke off the end. I guess I could sodder it back on. It would be easier to replace it. Then again.... I don't know what I'm trying to replace. I guess I need to figure out what part it is.

This is what I think it was attached too.

on distributor front set of terminals the right one is tach the left is battery

Originally posted by kschilling
This is what I think it was attached too.

the capacitor is for reducing ignition noise for your radio

kschilling,

Are there solder marks on the wire that look like those on the condenser? If they look alike, you've probably found the connection.

You could start the car, touch the wire to the end of the condenser and see if the TACH works.

bg489,

I think you have it backwards. If you look closely in the picture, you can see the words TACH on the left and BAT on the right. Right above that are (from left to right) C- GRD B+

In any case, he's not looking for where to attach to the distributor, he's trying to find out where to attach it to the signal lead that goes to the tach inside the car.

Originally posted by kschilling
This is what I think it was attached too.

thats is.

Do you have a wiring diagram for the car. If you have one you might be able to trace the diagram back to the color wire that hooks to the tach on the engine compartment side. If you don't do anygood I will see if I can find my diagram for my 73 Z28 I have it somewheres around the house, I am at work no so don't have access to it.
That wire in your hand doesn't look like it came off the capicator since there sure is alot of uninsulated wire on the end, it looks like it was just twisted to another wire in the engine compartment. The wire your looking for ought to be in the same wire loom that your distributor battery terminal wire is in, see if you can trace it back that way.

Originally posted by 73RS
Do you have a wiring diagram for the car. If you have one you might be able to trace the diagram back to the color wire that hooks to the tach on the engine compartment side. If you don't do anygood I will see if I can find my diagram for my 73 Z28 I have it somewheres around the house, I am at work no so don't have access to it.
That wire in your hand doesn't look like it came off the capicator since there sure is alot of uninsulated wire on the end, it looks like it was just twisted to another wire in the engine compartment. The wire your looking for ought to be in the same wire loom that your distributor battery terminal wire is in, see if you can trace it back that way.

looks like somebody has changed the tech wire anyway that wire thats going to the dist it a mighty big wire for the tech. id do what henry said and see if the tech works.

As we say in the Army...... HOOAH!!!!!!!!! That was it. I simply thought that it broke off a "male/female" connection somewhere in the wiring harness.

Yes, I did prep the wire and pre cut the end.... thought I would simply re-attach it and it would be done. Wrong answer.

My next challenge is to find a replacement. I've already hit the auto parts stores and all I get is the "Goat in the Headlight look".

I can sodder the end back on.

Question: Do I really need it?

If you bypass the condenser, you're liable to cause a lot of static in your radio. Also, it may be necessary as an interface between the tach and the output of the distributor. Does it work if you touch the wire where it broke off? If so, just solder it back on.

If not, pull the capacitor off and see if you can find some type of identifier/part number on it.