I should have supplied more information with my original message but I was trying to brief and not bore you guys hehe..
This gauge problem is in a 1965 Ultravan (motorhome) which is a Corvair powered unit. As I said, it has the original sending unit but the gas gauge has been replaced. I used a 90 ohm resistor to verify that it needs to see a 90 ohm sending unit to show 'full' on the gauge. The tank is a 30 gallon unit that would be a huge PITB to remove. Also, since it's unlikely that the replacement sender will fit, it's going to require some modification and the thought of drilling/cutting into the tank (gas explodes hehe) after draining seems a bad idea. unless the tank is filled with water vented etc... There is some confusion as to what resistance range the original sending unit had. Some report a 0 - 45 ohm version, some a 0 - 30 ohm version. Currently we measured the level of gas in the tank and got 1/2 a tank. The sending unit measures 14.9 ohms to ground hence I believe that it is a 0 - 30 ohm unit. Here is a not so brief description of the gas gauge/sender operation : *The fuel gauge needle is mounted between two magnetic coils. One coil is on the "F" side of the gauge* *and the other is on the "E" side of the gauge. Both coils are wired to the ignition circuit and receive* *battery voltage whenever the ignition switch is on. The magnetic coil that pulls the needle toward F* *(Let's call this the F coil) is grounded at the instrument panel and applies a constant magnetic force to* *the needle. The magnetic coil that pulls the needle toward E (Let's call this the E coil) has more* *windings for greater magnetic strength and is grounded through the variable resistor in the sender* *attached to the fuel tank float.* *When the fuel tank is full the resistance in the sender is high (30 or 90 ohms) which reduces electrical* *current and magnetic strength in the fuel gauge E coil allowing the F coil to pull the gauge needle to 'F'* *When the fuel tank is nearly empty and the float is near the bottom of the tank the resistance in the* *sender is at 0 ohms. The fuel gauge E coil receives full current, has enough magnetic strength to* *overcome the strength of the F coil and pulls the gauge needle to 'E'* I hope that explanation helps clear things up a bit.. I am going to make some new measurements today, hopefully one of which will be the resistance of the gauge and voltages for reference. The gauge is also a bit of a pain to get to. Thanks for your input so far! Kerry -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/38f7ea0a-a38e-4d84-b282-48644197c674%40googlegroups.com. For more options, visit https://groups.google.com/groups/opt_out.
