73 T Need Tach Help

[lespaul]

My tach is off. At idle it sits at 0. When I accelerate it comes up to the proper RPM, but floats around a little bit - especially when I ease off the throttle. Otherwise, the car seems to run fine.

I have checked the points and dwell. They are adjusted properly.

One clue. When I used an external device to measure RPM - off the coil, I got a fluctualting RPM reading at idle - even thought the car seemed to be idling steady. The readingt went from 200 to 500 to 900 to 500 to 1100 to 100, to 400 and so on. Just floated around. But, as I said, the idle seemed steady.

Any ideas where to start in my analysis?

[ossiblue]

Do you have a stock CDI set up?

[lespaul]

Ossi Blue.

I am not as familiar with the electrical side of this car as I need to be. I believe the car is set up as it came from the factory. But - what is the CDI and what does it look like?

BTW - do you have any pictures of your car? I am considering Ossi Blue on my eventual paint job.

TX

[ossiblue]

I asked about the CDI because I read some threads where some tach problems occur with aftermarket units unless special adaptors are installed--ie. MSD.

The CDI unit will be located in the engine compartment, left side against the fender wall along with the relays and fuses. If you have the original Bosch unit, it will look like a silver metal rectangular box with cooling "fins", approx. 3X5 inches in size. You can do a search on this site to see an example.

I have some pics of my former car but they are on the other computer. If you still want some, I'll send them to you tonight. I agree, it's a terrific period correct color!

There have been several threads about tach problems similar to yours, some having to do with dying alternators, coils, or CDI boxes. Try the search function and see what pops up.

[lespaul]

Thanks LJ.

If you have pics and can post them, I will enjoy seeing them.

[ossiblue]

lespaul,

Here are a couple shots of my previous ossiblue 69 912. Really nice color, IMO

[lespaul]

Beauty. Thanks for taking the time to send them. I am having trouble deciding between signal orange and ossi blue - but this may swing me to blue.

[RWebb]

prob. not the issue, but check all the grounds, and if you have points be sure they are in good shape

BTW - there are no bad blues...