Funky fuel gauge

[Gyrophoenix]

Coach: 2008 Holiday Rambler Scepter
Fuel gauge remains at Full until tank is about half empty, then sort of wanders down, sometimes even goes back up a bit. Never really accurate. Fill-ups are determined by mileage anyway, since the mpg is known, but it would be nice if the gauge worked. Best guess is a faulty fuel sensor inside the tank. Is there any way to replace that without removing the tank? No way I'm having that done....

Thanks.

 

[Mark_K5LXP]

The mechanical gauges in instrument clusters are "motors" and subject to errant operation. Generally the cluster will go through a reset/self test when you turn the key on and the gauges will often operate through their entire range before indicating their commanded values. So that's one thing to observe. Next would be to find the analog signal from the sender itself and see if it's resistance/voltage range is correct. Point being is it's possible it's the instrument cluster and not the sender, though my money's on a bad sender. You could use this as inspiration to drop the tank and replace the aging pump, and get a working gas gauge as a bonus. It's the kind of thing you do with forethought and intent at your convenience, like at the end of the camping season where you intentionally run the tank near empty, have a nice place lined to do the job, etc. Then it's only moderately awful.

Mark B.
Albuquerque, NM

 

[Onyrlef]

Coach: 2008 Holiday Rambler Scepter
Fuel gauge remains at Full until tank is about half empty, then sort of wanders down, sometimes even goes back up a bit. Never really accurate. Fill-ups are determined by mileage anyway, since the mpg is known, but it would be nice if the gauge worked. Best guess is a faulty fuel sensor inside the tank. Is there any way to replace that without removing the tank? No way I'm having that done....

Thanks.

If you have access trace the wires to the fuel tank.

 

[Gyrophoenix]

Thanks for the advice. Dropping/removing the tank from a HR Scepter is a major job. Quite expensive, certainly not worth it to make the fuel gauge accurate. I was hoping someone had a novel way of addressing the issue. Again, thanks.

 

[Don C]

Don't know if a OBD2 gauge/scanner/reader (such as OBDLink or Edge CTS3) would work with a faulty sending unit but if the problem is the instrument panel gauge it would give you a backup gauge.