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ok I have a 1985 f250, 4x4, 300-6, t 18,SCLB.
I am about to finally put on the good bed !
the fuel gage was always below E.
I never drove it except from the field where I got it to the tow truck.
I thought the tank was empty.
I went to put five gallons in just so I could move it around, but could only put in two.it was full.
the PO had replaced the tank .
the rear wiring harness is off.
is this the correct sending unit ?
I jumped the gage connector, did not move.
and where can I get a replacement? if needed...
There is no way to tell from the outside if that is the correct sending unit. There were many different ones but they all look the same from that view.
As for jumping the connector, assuming you went from yellow to black the gauges should fairly quickly go to full scale if it is working correctly. Do you have two tanks? If so, there is a switch to the right of the HVAC controls the determines which tank the gauge is showing.
And LMC, Jeff's Bronco Graveyard, NPD, and many others carry sending units. But if the gauge isn't working a new sending unit won't fix it.
The reason i ask as i have seen sending units for carbed trucks that have nut connection...no electric pump.
i dont have a/c.
yes i jumped between the blk/yellow.
i read somewhere that the sending unit grounds on the rear of the frame ?
If i pull the sending unit can i visually inspect it ?
And what am i looking for.
i need to get this resolved so i can get the bed on...
The ground for the tank is bolted to the frame with a 1/2 zip bolt right by the strap Black wire, they rust up and dont make a good ground. get a jumper lead to a known good ground and try to swing the gauge again. I got one from LMC they are not cheap and they dont have all of the models. So hopefully you find it, some times the float get saturated or the pivot loosens up you can make it alittle tighter by pushing the clip on a little further.
short the connector comming from the gauge for a few seconds the needle should move on the fuel indicator gauge
check the connector comming from the gauge it should every 1-2 seconds give a "pulse" voltage.
give us the ohms reading of the two pins on the tank..See if either of them is shorted to the tank metal surface. (Ohms of the following : pin to pin, pin 1 to tank, pin 2 to tank, tank to car ground)
Knowing that the gauge directly sends power to the tank, all of this should be safe, but i would do this with the truck outside, in the .1% chance something happens you wont lose the house also.
ALSO LOOKING AT THE BUTCHERY OF THE FUEL SENDER OUTLET. (OEM never has that splice with the compression fittings) something must be wrong with the sender, because it is absolutely not stock. If you do remove the sender, be epic careful because you know, gasoline likes going boom!
Patrick
when you say short do you mean ground ?
I grounded the yellow wire to the frame no response.
"check the connector coming from the gauge it should every 1-2 seconds give a "pulse" voltage. "
I am thinking your talking about the connector to the sending unit ?
so I can put a test light on it and it should light ?
A couple quick checks to see if the sender is suspect or not. Check for power at the connector (will pulse on/off after a few seconds) as well as ground. If those are both present, the sender is likely bad. If one or both are not present, you will need to track the wires to their source.
As stated, someone has modified the outlet on the sender by adding a compression union, dunno if this was done to repair a leak, or to convert to the EFI style "quick connect" fuel hose. I didn't think this style fuel line was used on carbed models, but I could be mistaken.
a voltage tester is needed for the wire running from the gauge. a test light probably won't turn on because the gauge never sends that much power in the first place
ohms are a measure of electrical resistance, measure with any multimeter. show us a picture of your multimeter i am sure it is on there.
also yes, the "quick" connect is standard on these ford OEM/Aftermarket fuel sending units, my 1986 carbed f-150 had the exact same
No power getting to the connector, means you need to start tracing the wire back to it's source. Somewhere along the way, there's got to be something cut/broken that's stopping the flow of electricity.
a voltage tester is needed for the wire running from the gauge. a test light probably won't turn on because the gauge never sends that much power in the first place
ohms are a measure of electrical resistance, measure with any multimeter. show us a picture of your multimeter i am sure it is on there.
also yes, the "quick" connect is standard on these ford OEM/Aftermarket fuel sending units, my 1986 carbed f-150 had the exact same
A standard test light will light up and blink. I've done this many times before.
Heck, even a 1.5V AAA battery has enough power to light up a 12V test light, though it won't be very bright.......
I knew the quick connections were used on EFI trucks, but wasn't sure about the carbed versions. Been too many years since I messed with a 85/86 carbed truck.....
There is no way to tell from the outside if that is the correct sending unit. There were many different ones but they all look the same from that view.
9275 Fuel tank sending units for these trucks are a real b!tch to look up, due to the many different variations.
Some have an ID number stamped on their face, which can be cross referenced to the actual part number...as long as you have a Master Cross Reference Catalog.
Besides myself, who on FTE has one a these catalogs?
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