grounding bob drake fuel sending unit
 

1936, still 6 volt, new fuel tank and sending unit. Continuity exists between tank and gauge. will grounding sending unit to metal floor of car be enough ( which I did) however unit still not reading. Should i move it to a heavier gauge ground source?

Re: grounding bob drake fuel sending unit
 

Grounding to a clean spot on the floor is more than adequate.
You most likely realize that the Drake units are "iffy" at best.

Re: grounding bob drake fuel sending unit
 

Agree.

Could be bad sending unit, or a bad gauge.

To test the gauge: with a helper watching the gauge, switch on, briefly touch the end of sender wire directly to ground. With zero resistance there, needle should move towards full.
If it does, assume gauge is good, must be bad sender.

Re: grounding bob drake fuel sending unit
 

Jay, on which end of the circut of the sender wire do you directly touch to ground? Is it leave sender wire connect to sender and then touch gauge end to a ground? or jump from ground at sender unit to sending terminal? hope this makes sense.
Mike

Re: grounding bob drake fuel sending unit
 

Disconnect wire from sender terminal, touch that wire to ground.

Or yes, as you said, leave connected to sender terminal, rig a jumper wire from sender terminal to ground. Will give same result.

Re: grounding bob drake fuel sending unit
 

Original gauge... Likely a King-Seely system. I do not really understand it but what I do suggests the sender sends pulses to the gauge and bumps the indicator, the more pulses the higher the indicator goes (don't ask me how).


Aftermarket sender... (used by most aftermarket gauges) senders use a rheostat (variable resistor) to vary voltage and the gauges is basically a voltmeter.


King-Seely gauges will ocassionally, but not always kinda work with the aftermarket sender. Empty could show as empty, Full could show as full, but anything between will be random to that gauge and sender.


There are some great threads on the subject with 747 explanations of how the King-Seely system works. Search for them. (747 jet... way over my head).

Re: grounding bob drake fuel sending unit
 

Yes, he has a modern sender which will never produce accurate readings on an original K-S gauge. But it should show something.
My understanding is he is getting no needle movement at the gauge. Probably a bad sender. Probably the tiny rheostat coil in the sender is broken open.

Re: grounding bob drake fuel sending unit
 

Thank you Jay, that is exactly what I needed to know. Now off to see what is what!
Mike

Re: grounding bob drake fuel sending unit
 

I don't know if i read correctly or not but by using a sender up into the 50's (still 6 volt) will work with the orig gauge, but i may be wrong.

Re: grounding bob drake fuel sending unit
 

Jseery gave us an explanation.

https://www.fordbarn.com/forum/showthread.php?t=165773

Re: grounding bob drake fuel sending unit
 

On my 46 the dash gauge wasn't registering after installing a new sender. Checked the connection at the tank and it was loose. Added a small washer and it worked.

Re: grounding bob drake fuel sending unit
 

I had the float sink on a new Drake sender. Put my original float on it, which was bigger and I had to bend the arm, and it works again. Just because it's new doesn't mean it's good.

Re: grounding bob drake fuel sending unit
 

The big unknown is what Ohm range would give a King Seeley quantity indicator a full sweep from E to F. The current pulse system didn't have the same range due to the way it controlled power at the indicator. The indicator function is the same theory but current control doesn't involve any rheostat. The float arm movement affected the movement of the sender breaker points on the bi-metallic regulator switch arm. K-S used a resistance wire spool and a carbon resistor to calibrate the system circuit. If you chuck the original sender and convert it to rheostat, the Ohm difference between E and F on the indicator need to match up with the resistance range that gets it there.

Ohm controlled quantity systems use specific Ohm values and from research, most are limited to three or four different values between different manufacturers. They should test a K-S indicator with a good variable resistor test aperatus to find what range effects it and manufacturer one that works. I think they just got one of the off the shelf units that's close and called it good. I'd be surprised if they care whether it works or not.

Re: grounding bob drake fuel sending unit
 

I have found, after too many length adjustments for my Drake sender, it reads full for a long period of driving and then down to 1/4 full quite quickly. That is when I head to the gas station. Today the gauge indicated about 7/8 full. I add 9.3 gallons. The worst thing is a Ford sender will not fit in the hole in the Drake tank. Had to buy a Drake sender. Purposely ??

Re: grounding bob drake fuel sending unit
 

Yep, the bungs are different. Some can use an adapter but I don't know which ones.

Re: grounding bob drake fuel sending unit
 

Wouldn't that be nice. Probably never see it happen.

Re: grounding bob drake fuel sending unit
 

No matter how important these issues are to all of us we have moved into the

"WORLD of IRRELEVANCE" !