That's weird!, Tach drops 1000 RPM at 4K, but car drives fine . . . Options

[anderssj]

I took the car out last night for the first time in a few weeks. While it ran great, the tach needle dropped about 1000 rpm every time it got near 4K. Drove the car about 25 miles and tach never read higher than 3800 rpm. When I should have been seeing around 4200 in 3rd, I was seeing about 3000.

Odd thing--or the good thing--was the car ran great, no missing, no problems with driveability, so I wouldn't suspect points/condensor (yet).

I've already checked the coil, all the wire connections are tight. The coil bracket is tight too, so the coil doesn't rotate or allow the wires to ground out.

FWIW, I had the dashboard apart a couple of weeks ago. I drew a picture, labeled everything, and thought I had it back together correctly--but there's always a chance I screwed it up (Dad used to say I could screw up an anvil (IMG:style_emoticons/default/dry.gif) ). If anyone can tell me which wires go to which terminals on the bottom of the tach, that would be a big help (the terminal numbers on the tach don't match those in my diagram).

Thanks in advance for your help and insights!

[anderssj]

Thanks!

I may try to pull the tach tonight and see if anything is loose.

Now if I can figure out what wire REALLY goes where . . . .

Update: Pulled the tach and cleaned things up a little. Also noted that the plastic housing at the bottom of the tach is marked: "12+" "1" and "-" I figure that means power for the gauge (red/white), tach signal from coil (black/purple), and ground (brown) respectively.

Didn't have time to drive it, but hopefully that will take care of it (if not, I have a spare tach I can try next).

Thanks again,

Steve A-