I am new on here and have a question about my fuel gauge . it is not reading any fuel and i have an half full tank , I took the hot wire to the sending unit in the tank and used a test light ,and the light pulses off and on with the key on ,is this normal . how can I check if its the gauge or the sending unit, I have a 66 f100 with a standard dash .Thanks Dan

 

Probably a sunk float. Pull the sending unit and check if the float has been compromised and is now full of gas. Float is available separate from the sending unit.

 

Thanks that was my next option but ,I didnt know if it was normal for the power to pulse like that . the truck had set for the past 7 years with old gas ,and i just picked it up last week ,that probably let it sink or leak ,thanks for the help. I really like this site and have used alot of information from here in the past, good bunch of people on here,Dan

 

The electrical pulse is normal.

 

Thank you very much

 

Dan, first off, like to take this opportunity to welcome u to FTE if I have not already done so. Welcome to the Family of Ford Truck Enthusiast!! , The fuel gauge, oil pressure, and water temp are tied into the Contant Voltage Regulator; a small metal box usually located on the back of the instrument panel, it regulates voltage and oscillates from between 0 and 9 volts. If the other gauges are working okay then the CVR should be okay. Suggest check the connections at the CVR, gauge, tank, and most importantly the ground connection. These vintage gauges arn't that reliable to begin with, I rarely will let the indicator get below 1/4 tank. It may also be the gauge, you can take a flashlight, I used a 2 D cell flashlight and removed the top, using alligator clips connected pos. side of flashlight to the connection on the gauge, and used the neg. clip to ground gauge to the on/off metal portion of the flashlight. The gauge should move to the full position if working properly. Believe there's a small set screw for slight adjustment on face of gauge. Replaced all the harnesses on the 65, added couple circuits, traced down few electrical gremlins using the Jim Osborn Reproduction Wire Diagram Manual. Purchased mine thru FTE Motorhaven, but majority of the Ford part suppliers carry them, or you can go directly to the source, Jim Osborn Reproduction and purchase on their website for around $7 plus s/h. Again, welcome, don't hesitate asking questions and post pic's if and when u can.

 

Welcome to FTE

COAZ9202B .. Fuel Sending Unit Float * / Available from Ford.

Fits: ALL 1957/79 Passenger Cars, F100/1100's, Bronco's and Econolines.

MSRP: $7.41 // FTE sponsor: Y2KFORDPARTS.COM price: $5.34.
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C1TF9276A .. In-Cab Fuel Sending Unit Gasket / Available from Ford.

Fits: ALL 1957/77 F Series Trucks with In-Cab Fuel Sending Units.

MSRP: $5.82 // Y2KFORDPARTS.COM price: $4.19.
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D7TZ9275G .. In-Cab Fuel Tank Sending Unit / Obsolete

Fits: ALL 1961/77 F Series Trucks with In-Cab Fuel Tanks / D7TZ9275G replaced C1TZ9275K.

There are a few of these remaining at FoMoCo dealers, obsolete parts vendors.
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B9MZ10804C .. ICVR = Instrument Cluster Voltage Regulator ** / Obsolete

Fits: 1961/66 F100/1100 / 1961/66 B/C/CT/H/HT/N/NT/T500/1000 / 1961/75 P100/500 (Parcel Delivery) / 1966/77 Bronco / Myriad 1959/66 Passenger Cars.

These can be found at autoparts stores, but...take the old one with you.

There are...at least 10 others used from 1957 thru 1987, none of which are the same!
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* The float is made from two pieces of copper soldered together.

Solder breaks down, gas seeps in, float slowly settles to the bottom of the tank.
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** When the ICVR begins to fail, the Fuel and Temp gauges do the Hula!

In other words, the gauge needles seem to have a mind of their own, and swing wildly back and forth.