Hi all,
I read a lot of threads about this issue but i cant make a right diagnostic of my problem because its symptoms dont really match anything i read!

Its a 76, the tach is going to 0mph when you turn the ignition on (from what i understood it means the circuit board should be fine), the needle isnt acting strange on idle, its fine...
Issue is that it wont go higher than 3000rpm, past 3000 it just starts flicking from 3000 to 3500 but wont go higher, and it goes down fine after that.

What could it be? circuit board? Filter? dirt in the mechanism?

Thanks a lot

C

 

I had that problem on a car in the past. Installed a tach filter and it started working properly right away.

 

I htought they already had a tach filter installed?
Could someone post a pic of where this filter is ment to be? I just want to make sure im looking at the right thing!

 

Its mounted on the Intake in front of the Distributor.

http://www.ecklers.com/Illusrate_pop...jpg&text=46137

 

Follow the tach lead from the distributor - the tach filter is usually within 12" of the distributor in that wire, mounted to the intake.

 

My gut tells me you have a board problem, but check the tach filter first

The tachometer in your car works off 12 volts, a ground and what is called a square wave signal generated by the distributor. The 12 volts and the ground are supplied to the tachometer by the printed circuit on the back of the speedometer and tachometer housing. The signal is supplied from the distributor through a filter and then straight to the tach.

This signal passes through a tach filter as mentioned above, mounted on the intake manifold. This filter is only there to keep electrical static from the ignition system from interfering with the signal to the tachometer.

18243

The tach filter should have a ohms reading from end to end around 500 ohms, so you can test it and see if the filter is good from end to end by using this figure. If you test the filter and it’s bad replace it. You can also do a simple by-pass of the tach filter by unplugging it from the distributor and the main signal feed wire. Then plug the main feed wire up to the distributor direct. This will not hurt anything for testing and if the tach comes to life you’ll know the filter is the problem. If the wire in the filter is loose or breaking this would cause the tach to function as you described above.

If the wire is broken from the end of the tach filter, you can in some instances strip off the end of the wire and drip a tiny bit of solder in there to attach the wire back. If this fails, I do have the filters in stock and you'll find them priced for forum members at this link: http://willcoxcorvette.com/product_i...ducts_id=26320

If you need more help post again!

Willcox

 

Thanks a lot....

Willcox, i have been looking at your website for a while and was wondering if you guys ship to europe and what kind of shipping and tax i have to expect...

 

Most of the parts shipped to Europe ship by USPS. Depends on the items. The UK has a different size limit on the parts by USPS so you'll really just need to send your list to sales at Willcox@Willcoxcorvette.com.

Willcox