Fuel gauge erratic readings

[biggercb]

I have never had a fuel gauge hooked up. The wiring in the Bronco isn't stock by any stretch.

I went to hook up the sending unit to the Sunpro gauge that has always been there, and I get a signal, but the gauge is very "jumpy".

I'm assuming it's because the gauge is hooked to a full 12V...and there isn't any IVR to pulse/knock down the voltage to the sender???

 

[DirtDonk]

Probably not. An aftermarket SunPro gauge is probably intended to work on 12 V. Not every manufacturer uses an IVR.
One potential issue is that the gauge isn’t designed for the Fords 73/10 ohm range.
Or loose connection.
Any way to find out if there’s a part number on the gauge?

What kind of rewire was done to the truck? Full harness, or just messed up wiring