I just replaced my fuel sending unit in the cab tank with a Dennis Carpenter unit C1TZ-9275K. The fuel gauge is only reading a little over 1/2 tank when testing the unit in the fully topped up position. Has any one had this similar issue? This is a 1966 F250.

 

Check to make sure there is a ground wire going from the sender to the cab body away from the fuel tank.

 

When grounding the center post orange wire to the body the fuel gauge climbs to F no problem. The person who sold me the unit says check the dash voltage regulator, but doesn't this indicate that the voltage is ok? Could the rheostat be a mismatch for this voltage? The ground wire is properly grounded to the body from the outer unit flange mount plate

 

I checked the grounds. even checked to see if the block was grounded to firewall. Pulled the new Dennis Carpenter fuel Sending unit. It reads about 70 ohms when empty and bout 10 when in Full position. this should be accurate. Tested the wiring again with the old crusty unit, I was able to get it to peg to F.

I just can't seem to get this new unit to peg to the F mark. So weird. Would adjusting the Instrument Voltage regulator do anything? i dont want to throw the stock setup out of wack for the other instrument on the dash.

Also, is there a thread somewhere explaining the proper sequence for removing the instrument cluster on a 66 Custom cab?

Any help is greatly appreciated.

 

Carpenter is living in the past (as usual), this C1TZ-9275-K sending unit was replaced by FoMoCo over 30 years ago.

D7TZ-9275-G (replaced C1TZ-9275-K) .. In-Cab Fuel Tank Sending Unit / Obsolete

Applications: 1961/66 F100/800 / 1963/69 N500/750 / 1967/77 F100/750.

Want a genuine Ford NOS original, instead of a made in China crap reproduction?

D7TZ-9275-G =

SWAFFORD FORD SALES in Richmond MO has ONE = 816-776-2288.

SMACKOVER FORD in Smackover AR has ONE = 870-725-3961.

NELSON FORD in Martinsville VA has ONE = 276-638-2331.

NOS PARTS SOURCE in Olathe KS has ONE = 913-220-5746.

COLLECTORS AUTO SUPPLY in Oroville WA has FIVE = 800-414-4462.
------------------------------------------------------------------
C1TZ-9275-K =

JST AUTOMOTIVE in Lebanon TN has ONE = 615-443-3086.

ANTIQUE AUTO SUPPLY in Arlington TX has TWO = 817-275-2381,

 

You might try bending the tab that limits the travel on the arm that holds the float until you get the proper reading. This may also require that you bend the float arm downward since the float will travel higher. If you are able to get it to read properly on full, I would also recheck the calibration when it is on empty since that will probably change too. I was thinking of trying this on my reproduction sending unit as well. Mine isn't off as much as yours, it goes about 9/10ths of the towards full when it is full. Seems like it should work, I just haven't had the time to try it on mine yet. If it works, let us know.

 

Hey Bill, I just found out the part is stamped D7TZ9275G, but the bag has the old part number. Thanks for the phone numbers!! (did you used to work at the big Ford on Colorado in Pasadena?) Yes an old wrapped wire style unit would probably be the way to go. But I'm concerned this unit is falling into spec via Ohm reading but is not allowing the gauge to climb to full F,. It has nothing to do with the angle of the float arm. (yet) It just seems like the resistance is "too resistant" at the full position, which is at the top of the printed circuit board style rheostat. I have inspected this unit under magnification and cleaned the contacts ect and it looks "fine". There must be something in this design that doesn't allow enough juice to get through once the tab travels up the contact path........Or the IVR is not a good match for this unit.....Some suggest maybe the tank selector switch could be pert of the prob...

Does a 66 Instrument Voltage Regulator have an attenuation pot? And where is it?

 

B9MZ-10804-C .. ICVR = Instrument Cluster Voltage Regulator, bolts to the backside of the instrument cluster (Motorcraft GR-508) / Obsolete-Available at autoparts stores.

Applications: 1961/66 F100/1100 / 1963/69 N/NT/T500/1000 / 1966/77 Bronco / 1967/69 F800/1000 / Misc 1959/66 Passenger Cars, including 1965/66 Mustangs.

When this little charmer begins to fail, the fuel and temp gauge needles "do the hula," swing wildly back and forth on their own.

When the little charmer burns out, the gauge needles are as dead as Julius Caesar, will no longer move.

Replace the puppy, the gauges will wake up. If replacing it, make sure to take the original to the autoparts store to match it up.

There are TEN other FoMoCo ICVR's, more from other auto makers. Most chain autoparts store parts clucks in today's world haven't a single clue.

 

Number Dummy, no hula here as far as I can tell. The other gauges seem fine. the only Hula we're gonna get is when I solve this issue. I might try to take this Sending unit and hook it up to another 60's f series and see what happens. Other than that, my secondary tank has no read on the unit so, when i drop that tank and figure out what kind of unit that is maybe this scenario will make sense. I am new to this :-0

My choices seem to be:
Try (buy) alternative sending unit (my old one works, sort of)
try (buy) new IVR
try Sending unit in another truck (to verify it is good/bad)

 

I received another sending unit. it seemed to work fine (out of the tank, when pushed all the way to top position). Now with 8 gallons in the tank, it only reads at the "E" mark. And now that I double checked it by pulling it back out, it doesn't seem to give a proper reading at the half way mark, sorta like the last one. Can an Instrument cluster Voltage regulator cause this lower reading? I did test the ground going to the unit and like i said before, the guage climbs to Full when the wires are touched together.

 

I know this is an older thread but maybe get some help anyway?

I have a 73 F-250 that I got about 2 months ago, and got this same sending unit C1TZ-9275-K for my in-cab tank, from Dennis Carpenter. I know it has about a half tank of gas, but when hooked up and installed it reads full, ohm readings are within parameters and ground testing the guage, it swings to full. I even ran a new wire straight from the sending unit to the guage wire, same reading, ground is good, even sanded to the mettal and sanded the connector.. I am at a loss. Other guages seem to work fine, so do not think it is the IVR

Is there something I am missing? is there an aftermarket guage I can get that will work with this sending unit?

 

Just needs calibration. Look for the set screw where arm attaches to sender innards. Adjust float arm so gauge indicates a little above Full mark when arm is at the upper limit of travel. Most fuel gauges will read full for quite a while and then start to decline.

 

Well, thanks for the response Tedster9, but come to find out, it was the IVR, on a whim I pulled the one out of my 76 F-150 and bam... it works correctly, empty, full and at half tank.... glad i got it working, but will probly still carry a couple spare gallons, just in case.

 

Updated: January 21, 2016.

 

The key symptom there, it will affect both fuel and temp gauges. You didn't mention that! Glad you got it fixed though.

Bum fuel gauges are no help at all. You can kind of slap it and get an idea, another advantage of the in-cab tank.