Skip the auto shop - Our mechanics make house calls

Q: My new gas gauge should read from about 10 o'clock for empty and about 2 o'clock for full. My needle goes to about 5 o'clock.

asked by on

I have a 54 Chevy 3100 P/U. The original gas gauge was not working. I suspect the previous owner burned it up when they converted to 12v. I can put a volt meter on the lead wire and it reads 12v to ground. I purchased a new 12v gauge. When I installed it, the needle on the gauge swings past full and buries the needs almost 180 degrees opposite the half tank mark. If referencing a clock, the gauge should read between about 10 o'clock for empty and about 2 o'clock for full. My needle goes to about 5 o'clock, way off the scale. Nothing changes when I disconnect the sending unit. The needle does swing back when I disconnect the lead to the gauge. Do I have a bad (new) gauge, do I have a bad (miss-matched sending unit, should be 0-30 ohms unit) or could I possibly have the two wires on the gauge reversed?

My car has 100000 miles.
My car has a manual transmission.

A: You would need to see if the sending unit i...

You would need to see if the sending unit is shorted to ground. If you test it with an ohm meter you should get somewhere between the 5 and 30 ohms. If you are getting 5, then the gauge will be at full; and if you get 30, it should be at empty. If you are reading too low on ohms, then you have a shorted sender. If you’d like some help looking at this, a technician from YourMechanic can come to your car’s location to inspect your electrical system in person and let you know how to best proceed.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Why does my Tahoe start with the fuel pump relay pulled out or left in?

Hi there. Check to see what relay you have pulled. If indeed you removed the fuel pump relay and the engine still starts up, then check the oil pressure switch. An oil pressure switch will kept the engine running as...

Q: How many miles can I drive on empty?

Every vehicle is a little different when it comes to how many miles you can drive when your low fuel indicator first comes on. The fuel gauge is an estimate of how much fuel you have in your fuel tank....

Q: The fluid in the power steering pump is overheating.

Hi there. There is a blockage in the system causing the pump to purge and build up to max pressure. Check the hoses and see if there is any issues with fluid flow. If the steering is easy to move...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...