Ultralite gas gauge does not read true

[durk]

The gas gauge (ultralite) reads full when the tank is full but stops at half tank or half full and will not read any lower. Is this a common problem or is my gauge bad? This is with the sender out of the tank and grounded to the frame Hold up on this as Iam going to town and get a new sender an I will repost after I install it

[mikeinatlanta]

Having no direct knowledge of your sender or gage... You sender and gage need to be a match. The gage interprets a signal (impedance on traditional gages) as empty, full, and everything in between. The sender is designed to give a signal for the gage to interpret. Assuming the components are not faulty, the condition you describe would be indicative of the gage and sender not being an appropriate match, meaning the sender's empty signal is interpreted by the gage as half full.

You could verify this by checking the sender's and gages specs. Each should have a resistance range in the specs and they should match. You can verify the sender meets spec by checking resistance over its full range. I don't know about your particular gage, but most modern gages can be adjusted to match common sender outputs.

My guess for you is that you need a sender to match the gage. Second guess if the ultralight is capable is to calibrate the gage to the sender. Least likely is that either component is actually malfunctioning.

[ProJoe]

Just to add onto what Mike said, yes the sender and gauge need to match. If you are unsure of your sender you can always get a good operating range by measuring the resistance across the sender with a full, and empty tank (or just remove it and move the arm manually). This will give you the operational range of your sender and you can get a gauge to match. Here is a list of Autometer gauges and you can see the ranges listed on each gauge like 0-30ohm, 0-280 ohm, etc.

[Jeff Kleiner]

...I am going to town and get a new sender an I will repost after I install it

Before blindly replacing the sender break out your ohmeter and check the resistance with the float arm at "full" (158 ohms) and "empty" (16 ohms). If those values are what you have the sender is not your problem.

Jeff

[stack]

Before blindly replacing the sender break out your ohmeter and check the resistance with the float arm at "full" (158 ohms) and "empty" (16 ohms). If those values are what you have the sender is not your problem.

Jeff

He could have an older sending unit. Need to measure it out


Ohms/Resistance
(Empty/Full) Popular Models
0-90 Ohms most GM cars, 1965-up
73-10 Ohms pre-1989 Fords & most Chryslers
240-33.5 Ohms Industry standard, works on many popular cars
0-30 Ohms most pre-1965 GM cars
16-158 Ohms most '89-up Fords

stack

[Papa]

Another possibility is that the float on the sender is binding or hanging up on something and not moving its full range.