Replacing the fuel sending unit.

[WolfSpring]

I should get my new sending unit in the mail tomorrow. Changing it out seems really simple, I've looked in the manual and I understand what I'm doing, but the key question I have is do I need to drain the tank? The sending unit is on the top of the tank and easily accessible by tilting the seat forward so i don't have to remove the tank.

I did search for this and found nothing about needing to drain the tank, though it seems most who have replaced it do drain the tank and even remove it if need be.

Thanks.

 

[Cheepjeep85]

you don't need to drain the tank unless you are removing it, you don't really have to drain it then, but it sure would be heavy. most people drain the tank because on later models its hung up under the rear and you have to remove the tank to replace the sending unit, and if its full it would be hard to handle.

 

[WolfSpring]

Thank you for the reply. I'm slowly learning this stuff and every step is a new challenge.

 

[Sasquach]

In your case with the tank under the driver seat you don't need to anything more than remove the 5? screws and replace the unit. Obviously no smoking or flame of any kind and be carefull not to drop anything in there when it's apart.

 

[Cheepjeep85]

thats sound advice as well ^^^^^

 

[WolfSpring]

well i replaced the sending unit. the old one was cork... i had to bend the pole a little so it would fit right and it is showing the tank at full even though there is a good two inches missing from the top. its acting just like the old one so far but without draining the tank i have to just drive and wait, still gonna use the dipstick just in case. any other thought on what might be wrong? before the change it showed full then flakey and would drop to 1/4 tank and be empty.

my appologies for sentence structure and grammar im on my ipad

 

[WolfSpring]

I replaced the gauge and got the same problem. The tank I'd say is about 3/4 and it's reporting full. I took the old sending unit and hooked it up to the gauge and moved the unit the gauge moves from about 1/2 tank to full it will not go below half a tank at all. On both the new and old gauge. Tommorow I will take the new sending unit out and play with it as well. I would guess I need to take resistance readings at full and empty and match them up. Maybe the new one isn't sitting right inside the tank, either way I'm at a loss here except to just play around and get it to work.

 

[Sasquach]

I say check the new one same as you did your old one, there may be some delay in the reading too?

Sounds like my camper truck, last trip the guage was reading 1/4 tank but going more off my odometer I knew it was time so made a stop and put 26.5 gal into a 26 gal tank? Gas guages never seem to be too accurate.

 

[WolfSpring]

So I figured it all out. fuel sending unit is working fine, 10 full 70 empty. Problem is someone told me my CJ is an AMC so I bought the AMC fuel gauge, come to find out that I need the Ford/Chrystler Fuel gauge which is 10-72. I pick it up tomorrow after work. Only down side is it's a 2 inch gauge and my hole is much bigger gonna need to redo the dash by the time I get all the wiring and gauges fixed.

Thanks for the pointers.

 

[Sasquach]

So I figured it all out. fuel sending unit is working fine, 10 full 70 empty. Problem is someone told me my CJ is an AMC so I bought the AMC fuel gauge, come to find out that I need the Ford/Chrystler Fuel gauge which is 10-72. I pick it up tomorrow after work. Only down side is it's a 2 inch gauge and my hole is much bigger gonna need to redo the dash by the time I get all the wiring and gauges fixed.

Thanks for the pointers.

Good job
Sounds like you will be helping us out!

 

[WolfSpring]

Got my Equus Ford/Chrysler fuel gauge today put it in powered up and BOOM half a tank, which the sending unit is sending out 30 ohms 70-10 is 60 1/2 60 is 30 there for it is reading right. Lesson learned, the fuel sending unit is not an AMC lol. FYI this is the unit I bought:

Original Replacement Parts 914850 - Fuel Sending Unit for 55-83 Jeep® CJ-5 with Under Seat Mounted Gas Tank & Non V-6 Engine - Quadratec

And this is the gauge

Equus 7361 - Fuel Level Gauge | O'Reilly Auto Parts

I do not endorse either site or advertise but those two units work great together.