I'm in the middle of an EFI/AOD swap from a 1990 Lincoln Town Car (fuel tank included in the swap) into my 69 F-100 & I'm having trouble getting my fuel gauge to work. I've hooked the fuel gauge sender wire from the Town Car fuel tank (brand new pump & sender) to the orange fuel gauge wire that's in the F-100. I've grounded the fuel pump/sender but I'm still not getting a read out on the in dash gauge. I've sent power thru the orange wire & I've gotten the needle on the fuel gauge to go up, so I know the gauge itself functions.

I'm assuming there maybe some difference in the "technology" (old vs new) that is causing my problem but I'm not sure what to do to make it work. Can anyone help me figure how to make my fuel gauge work?

 

No one knows how a fuel gauge works?

 

i'm no electronics professional, but:

the basic theory- the float in the tank rises, which moves an arm. the arm is attached to a resistor, so as the arm moves, the electrical resistance in the circuit changes. this change in resistance is what the gauge is measuring.

you are assuming that the resistance range of the Towncar sender matches what your F100 gauge is looking for. i have no idea whether or not that's actually the case.


you may want to float (ha!) this question down in the Electrical forum. there's a guy down there who really knows his stuff.

 

Thanks Rusty. I'll give that forum a try.

 

Could be a resistance problem, if resistance scale does not match the gauge will not work right. Did you use a new fuel meter sender for the orginal truck gauge or for the swap.

 

I put a brand new fuel pump w/sender in the tank.

 

If you are using the orginal gauge that is most like likely your problem. Senting units have a different scale, i.e. one might from 0 to 90 ohms another might go from 90 to 180. As the arm in the tank goes down/up the resistance changes and the gauge reads it showing fuel level. I tried to find the resistance for the lincoln but could not find. I'am should the resistance would be different from the lincoln sending unit to what you had in the truck.

If you got instr. with the sending unit the range might be on it some where.

Here are some examples.
http://www.summitracing.com/search?k...g%20unit&dds=1

I'am not saying get the correct ohm rating would fix the problem not an expert. I would think even a incorrect ohm scale would give you some reading but I could be wrong. If you still have the sending unit from your truck you could hook it up and see if it works. If so the sending for the lincoln is the problem. You don't have to install the old one in the truck just hook it up and make sure it is gnd. correctly. Move the arm to see if the gauge moves.

 

Any idea what the range is on the F-100 gauge?

 

Sorry no but I would think you could check both units by hooking up an ohm meter and find out. Should get you close enough to see how far your scale difference is. If ND checks in he should know.

 

Thanks. I'll try that but I'm thinking it'll be easier to use an aftermarket gauge. I just hope I can find one that fits into the instrument cluster nicely. Any idea if the in dash temperature gauge works the same as the fuel gauge or will I be able to hook up the F-100 gauge to my Town Car sensor?

 

for the temp gauge- can you just use your old one on the new engine?

 

I don't know, can I? I'm hoping so but I'm not sure if the temp sensor on the Town Car is a temp light or a temp gauge sensor. I'm pretty sure the dash on the TC only had a temp light to indicate overheating as opposed to an actual temp gauge. Do the temp gauges work the same as fuel gauges?

 

I have looked for aftermarket gauges not easy if you want keep the orginal look. The gauge needles on our trucks are on the top most aftermarket are on the bottom. There was on another forum a way to use sunpro gauges but I can not find it back. ( I will look some more) Also the gas gauge was not part of the exchange. I forgot there is like a small volt reg. on the back of the cluster, if bad I don't think the fuel gauge will work. It is expenseive to buy new but you can always go to the junkyard and get one cheap. Here is some info on the gas gauge.

Fuel Tank Sending Unit Tech -.com

Found it

http://www.fordification.com/forum/v...st=0&sk=t&sd=a

 

if the threads fit, sure- screw in your old sender and hook it back up.
if the threads don't fit, maybe you can find an adapter.

if the TC had a light, and your F100 has a gauge- the TC "idiot light" sender is not going to operate your truck's gauge.