Gas gauge and speedometer problems on my 69.

Discussion in 'General Ranchero Help' started by paxpwr, May 24, 2019.

  1. paxpwr

    paxpwr In Second Gear

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    The gauge was tested and works on a bench. It reads half full when tank is filled and empty when tank is half full. Is there an adjustment at the sending unit and if so how does it work?? The speedometer comes un hooked at the gauge pod. This push on don't want to stay pushed on. Any suggs ?? (no super glue or duct tape p[lease)
     
  2. paxpwr

    paxpwr In Second Gear

    Messages:
    52
    gauge reads half full when is filled, empty when is half full, Is there an adjustment at the sending unit ? if so how ?? Gauge works on bench test. Push on speedo on back of gauge pod won't stay pushed on. Any suggs ?? (please-no superglue or duct tape)
     
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  3. Cindy

    Cindy In Maximum Overdrive SILVER MEMBER

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    Cochise's gas gauge works when it wants to. Seems to read better in the colder weather for some reason.
     
  4. burninbush

    burninbush In Maximum Overdrive

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    Best guess from what you've already reported is the IVR -- instrument voltage regulator. It's mounted to the back side of the cluster.

    Not sure about the speedo cable, suggest that the mounting gizmo (plastic) is broken.
     
  5. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    The end on mine finally broke, so to keep it engaged, I pull the cable into the car an inch or so, then push the cluster on to it. Working so far....

    The gauge sender arm should be checked, as well as making sure the float itself is not partly sunk. I've seen Ford brass floats have a pinhole allowing gas inside, giving wildly wrong readings.
     
  6. colnago

    colnago In Maximum Overdrive

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    I had to bend the arm on my '67 F250 to read correctly.

    Joseph
     
  7. colnago

    colnago In Maximum Overdrive

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    What do you mean, "push on speedo on back of gauge pod won't stay pushed on"? If you're talking about the speedo cable, it screws into the back of the speedo. If you're still talking about the gas gauge, I haven't a clue.

    Joseph
     
  8. Hillbilly

    Hillbilly In Maximum Overdrive

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    There are two distinct methods of connecting the cable housing to the speedo. You obviously know about the screw on version that was standard for many years. Somewhere in 1967 they came up with the next design that used a plastic clip to anchor the cable end to the speedo. It was basically a formed plastic ring on the cable end that had a tab you squeezed to deform the clip enough for removal or installation. It more or less popped over a flared end built onto the speedo housing in the position where you would previously screw the cable retaining nut. Cheap to make and quicker to assemble on the line. It can be a real pain in the rear to disconnect on some models of Fords. Gas guage is a whole nother' problem. On Cochise, if the factory temperature guage reads even remotely correct I would think you need to check all the connections between the fuel tank and the gas guage. Both the temp and fuel guage are powered from the same source. I am not sure if your Ranchero has a separate wire harness going to the rear. If it does, there will be a multi wire connector hidden behind the driver's side kick panel or located under the carpet in the area of the dimmer switch. The connector plugs hidden under the carpet are prone to corrode from years of wet feet dripping on the carpet right where the connector is located. It is just another annoying quirk of keeping things working on older cars.
     
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  9. 72GTVA

    72GTVA Administrator Staff Member

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    Reads like an inconsistent ground to me - like a rusty screw through an eyelet back in the rear where the ground wires (black) attach to the body. I've had more than one episode of flaky tail/marker lights and schitzophrenic fuel gauge that was corrected by removing the tail light housings on both sides, cleaning the ground eyelets and body connection points and shiny new zinc plated screws to reattach. 30 minute job, removed a lot of guesses and stress.

    Bonus points in the karma world are awarded for pursuing Hillbilly's suggestion of checking the connector for the back harness up by the driver's feets (in other words, that is also a good suggestion - I'd do both on a slow day just for the OCD in me).

    By 1969 most Fords had transitioned to the slip on speedometer cable at the speedometer, the slip on have a nylon ring which on one side has a boss that captures a groove in the speedometer base, on the opposite side from the boss is a tab that you depress to release the boss from the groove. On aged cables, the nylon gets rather hard and sometimes it takes a lot of effort to fully seat the cable. The image captured from NPD shows the style used 1969 and up.



    17260-7a_20180411210401.jpg

    Suggest you verify which cable you have, the one with the threaded end or the push on type. If the push on type, try to ensure that it is fully seated and the boss has captured the groove. You might need to pull the cable down to where you can visually determine if the boss is still present (sometimes when they are forced off the housing they will break off). I had one with a broken boss that once I had pushed the cable on firmly it stayed connected pretty well until I had the time and Rancherobuck$$$ to replace the cable.
     
  10. colnago

    colnago In Maximum Overdrive

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    Gents,

    Thanks for the education. Both of my old girls use the screw-on speedo cable. I didn't know about the other. That's what I love about this group; I'm always learning.

    Joseph
     
    Last edited: Jul 13, 2019
    Cindy likes this.
  11. 72GTVA

    72GTVA Administrator Staff Member

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    Yes, the sending unit can be adjusted - not as simple of a process as one would hope, but doable. The steps are something along these lines:

    After verifying ground connections to the back of the car are good and there is some form of metal to metal contact between the tank and the body...

    Note: *You will need a new sender to tank o-ring seal in all likelihood.*

    1- When the fuel has been run out of the car to the lowest possible level that you are able to do (or drain the tank (preferable)), remove the sending unit from the tank. Inspect for defective float, that the fuel strainer sock is in good condition, and that the sending unit/fuel pickup assembly is reasonably free of rust. Verify the float arm is able to travel the full range of motion. By visual association see if you can glean the angle of the float arm relative to an empty tank. Your problem may be that the float arm is bent such that it prevents it moving properly in relation to the level of fuel in the tank.

    2- Bend the float arm such that with an empty tank the float would be at the bottom of the tank. Temporarily install the sender, add about 3 gallons of fuel, and check the gauge. It should read just barely above empty. Remove the sender and adjust the float arm to achieve that reading, a little trial and error may be needed as you step through this. Once you are satisfied, reassemble the sender to the tank with the new o-ring, fill the car. You should have a full tank or above full tank indication, and you will probably have a full tank indicated until you have run a few gallons through. This is normal for most Fords of that era.

    Some other members may have a better set of techniques for stepping through this process - this is the one that worked for me. YMMV. Good luck with your efforts!
     
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  12. andrewok1

    andrewok1 In Maximum Overdrive GOLD MEMBER SILVER MEMBER

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    I have used that exact proceeder 3 + TIMES AND COME OUT perfecto !!!!!!,
     
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  13. beerbelly

    beerbelly In Maximum Overdrive SILVER MEMBER

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    I did almost the exact same thing on an old Chevy LUV that would never read Full, but always went way below empty. Pulled the tank and found the sender arm drastically bent. How? I'm guessing someone tried to siphon gas and got hung up on the arm. So I bent the arm straight, and perfect.
     
    Last edited: May 25, 2019

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