GM to Z Converter

[briguy280z]

Excellent it finally works!

Ok I replaced the 1k0 with a 3k3 but still very little change. So i replaced
it with a 5k6 for some reason this worked fine. Worked the way it was
designed.

I tore open the guage to see how it works. I consists of two bi-metal
springs and when heated they bend according to how much heat.
One bi-metal moves the neatle from empty to full. The other breaks
contacts between power and unit line (current line). I believe the second
one is put in so that there is a fail safe. PULSING is caused by this bi-
metal breaking contacts. It was very hard to find the true current draw
with this pulsing going on. Otherwise I changed R5 to 5k6 which gave
control of the circuit. The everything else worked perfict i still have to
adjust 0 point but that was planned.

I got to make a Electro Tech sticker so i can advertise when the car is
completely finished.

Thanks for all your help i will keep intouch if any other problems come
up.

Briguy280z

 

[john1]

Hi Briguy, and Mechie,

I am most pleased that your gauge is now working ok.
And hats off to mechie for his working design.

As to the continuous pulsing, my guess is that the
petrol gauge may be the only gauge of this type on
the panel, so maybe they put the 'stabiliser' inside
it? that would explain why it has the three wires you
mentioned before. One to the sender unit, one to ground
and one to the 12v supply.

I feel it is unlikely to be any form of fail-safe or
overload protection.

I would like to see some more pictures of this project
if thats ok with you.

Regards, John