Ok grounded it is than

 

Can you guys give me your opinions, I will copy and paste here a post I made previously but have not seen a specific response too, thanks to another member here I have found a 67 F-100 fuel tank sending unit which is for the 18 and 19.5 gallon tank and the seller will hold it for me until Monday when I get back with him................. The entire post can be found here if I happen to of left out any pertinent info below.

https://www.ford-trucks.com/forums/1...ce-values.html



I have a 52 F-7, 12 volt new harness.
I am using 80-86 gauges, I am using the original 52 F-7 fuel tank, I need to find a sending unit for that upright tank, as I am sure you can understand that 80-86 sending units just are not going to work because of their configuration.

Ford used its last behind the seat up-right tank in 77 so I am thinking that I need to try and get one of these units. I am not sure what the original capacity was for the F-7 fuel tank, I looked in the shop manual and they are using alphanumeric codes to describe the models but I think it may be 20 gallons

Looking at this chart <table id="ncode_imageresizer_warning_2" class="ncode_imageresizer_warning" width="400"><tbody><tr><td class="td1" width="20"></td><td class="td2">Click this bar to view the full image.</td></tr></tbody></table> it would seem that the Ohms reading would be the same for these sending units and should match the gauges that I plan to use in my truck.

I believe that in 77 they had a 19 gallon tank behind the drivers seat available but still need to confirm this.

That may be as close as I could wish for, worse case it sounds to me would be that it will read empty when I still have about a gallon of fuel in the bottom of the tank.

I understand that there will have to be some modifications to the top of the sending unit to have it bolt to the top of my tank but I dont think that will be anything too extreme.

 

I know my 58 was a 16gal tank. The height of the tank is the determining factor. As long as the distance from the top to bottom matches and you can make it fit your tank, you should be ok. My 77 had only the front (side) tank originally.

There is one error in that chart, 87-88 F series still used the bimetallic gauges, the magnetic ones were introduced in 1989.

 

Thanks for the confirmation

 

You are quite welcome. I helped a friend do his 1955 Dodge pickup so know about fuel tank gauges and setting them up.

 

The chart is also wrong about the resistance. Full scale on our gauges is 10 ohms, and empty is 72, which is exactly the opposite of what is shown and different values as well. And, by the way, mid-scale is 22 ohms. That's from the factory shop manual, and was confirmed by my testing in the ICVR thread.

 

Yes I noticed the swapping of the numbers, so what is your opinion about my fuel tank/gauge project?

 

If the sender fits, and has the resistance values it should since it was apparently used with bi-metallic gauges, then you should be able to adjust it by bending the arm to get it to read right on at least one end. If it were me I'd want empty to be most accurate and bend/adjust the arm for that. Anyway, it should work.

Also, you should know that there is an 8 - 10 ohm in-line resistor in the wiring someplace ahead of the ICVR. I believe it is crucial to the operation of the ICVR, so if you make your own harness don't forget that. Someplace in the thread I discuss the resistors I used to simulate that one and how hot they got. You might want to read what wattage they were and get a bigger one.

 

Here is diagram of the IVR circiuit from an '86 shop manual:

http://imageshack.us/a/img72/3723/460tankselect.jpg

As Gary said:
Notice the 8 to 9 ohm resistance wire feeding the IVR.
The IVR must be grounded as shown in the diagram.

Also:
All 3 senders Fuel, Oil pressure and, Temp MUST have the same Ohm scaling as found in the '80-'86 applications.
If not, nothing is going to work right. That is even if you did get a working fuel sender, the IVR expects the other senders to be similar. They are all 3 tied together in a parallel circuit

 

True. But, if a real voltage regulator was used instead of an ICVR then the gauges won't influence each other as long as the overall load doesn't exceed the limits of the regulator. Again, I wouldn't use an ICVR on anything I cared about.

 

I installed this when I had my cluster apart and can attest that it works very well. After learning how the original worked I couldn't bring myself to reinstall it. Very crude design, never mind that it was ancient technology by 1970's standards even!

 

Amen! Well said and mutual feelings.

But, would you do me a favor and go to that thread and say essentially the same things? I'd like to get testimonials so others can see what the thinking is. And, if there are any learnings, such as how well it works or doesn't, and suggestions on installation that would be appreciated.

 

I would imagine the newer electronic regulator works much better than the old IVR, but it's one of those cases in my opinion that the IVR was good enough for what it did. I have never had a problem with any of the gauges reading correctly in any of the vehicles I have had(unless it was a sending unit failure), though I really only care about the fuel gauge. Any vehicle I cared about always got aftermarket gauges with numbers. You have to think about the point of it all, having a very accurate and stable power supply for a gauge that only has "NORMAL" on it's face.

Which brings me to another comment; I have never had a problem with the factory IVR running one gauge. I think I am seeing hints that if you do not have the correct gauges, and all of them working, that the ones that are left will be inaccurate. In theory this may be true, but in practice I have never seen it. Like I said most of the vehicles I care about, I have disconnected the factory oil pressure and temp gauges, and used aftermarket. I have never had a problem with the fuel gauge suddenly being out of calibration because of this.

Keep going, I see the engineering and thinking going into it, but I don't think it's a real problem myself.

 

Thank-you for the diagram, that will help, stupid question maybe for you but where might I get one ...... 8 to 9 ohm resistance wire feeding the IVR........locally here I hope? Radio shack ?

Is one any better than another, that ICVR was waay over the top of my head overall but from what I was able to understand it was a big plus for me in learning how these systems operate.

 

Do you still have access to the vehicle you got the cluster from? Just cut the resistance wire from it.