What are the Fuel Gauge Sender Resistance values?

T

Twilightoptics

NAXJA Forum User

Location

Vancouver, WA

• Nov 28, 2009

• #1

Did a search and couldn't find the numbers.

What are the resistance values for an '87 Cherokee Fuel Sender? Fuel and Empty.

My gauge reads very very lazy and I'd like to start diagnosing it.

Thanks
-Paul

 

joe_peters

NAXJA Forum User

Location

Grants Pass, OryGun

• Nov 28, 2009

• #2

Per FSM 90:

Empty ~ 0 ohm

Half ~ 44 ohms

Full ~ 88 ohms

 

T

Twilightoptics

NAXJA Forum User

Location

Vancouver, WA

• Nov 28, 2009

• #3

Awesome! Thanks

I got about 2.6 empty and 92 full. Close enough! I figured with as much GM stuff on here it'd be the typical 0-90 type gauge.

Looks like I'll chase the wire down and check out what it reads at the gauge.

 

T

Twilightoptics

NAXJA Forum User

Location

Vancouver, WA

• Nov 28, 2009

• #4

Alright I plugged the sender in and worked it by hand.... Gauge reads full and empty respectively. WTF.

The float ball doesn't seem to have fuel in it?!



Checked the wire at the gauge. Reads 10ohm empty, 92ohm full..... Maybe the gauge then?


Took the float off completely. I hear a little bit of fluid in it. Guess that must be the culprit.

 

Last edited: Nov 28, 2009

T

Twilightoptics

NAXJA Forum User

Location

Vancouver, WA

• Nov 30, 2009

• #5

So I replaced the float. Key on gauge works fine moving the float by hand. Installed in the tank pump on, it reads half full. Where are the main grounds? I've found a ground behind the dizzy, and the strap from the head to the firewall.

 

joe_peters

NAXJA Forum User

Location

Grants Pass, OryGun

• Nov 30, 2009

• #6

Is the half-full reading incorrect?

The biggie grounds are batt to block, head to firewall, ICM/ECU/o2 to dipstick tube. You will find other grounds for the headlights, instrument panel, etc., close to where the accessories are. There is a cluster of grounds in the rear of the XJ for tail/brake/turn lights.

 

T

Twilightoptics

NAXJA Forum User

Location

Vancouver, WA

• Nov 30, 2009

• #7

Reads half full when the tank is full. Working the sweep key on by hand reads properly. Even key on now with the sender installed and a full tank it only reads half.

 

joe_peters

NAXJA Forum User

Location

Grants Pass, OryGun

• Nov 30, 2009

• #8

Bent float arm, bend it downward so that the float must rise higher.

 

T

Twilightoptics

NAXJA Forum User

Location

Vancouver, WA

• Dec 1, 2009

• #9

Are they supposed to be bent? The rod was dead nuts straight from pot to float.

 

joe_peters

NAXJA Forum User

Location

Grants Pass, OryGun

• Dec 1, 2009

• #10

It would seem to me that the float, which is new, would be trying to float on top of the fuel and that if the rod was in the proper shape the rod would be at the end of the resistance winding, but what sounds like is happening is that the float is all the way up and the part of the rod contacting the resistance windings is contacting at the 1/2 way resistance value. Bending the rod some at the end closest the float should allow the float to return to its correct "floating" position but the bend would allow the other end of the rod to move farther down.

Make sense?