Jimbos01hd

My 01 2500 has a fuel gauge issue. When I first start it it shows empty.. Then it will go up a little, then drop to empty then go up a little more and keep doing this until it reaches the actual level. I filled up the other day and it seemed like it took about 10 cycles like this to reach the full mark. After it reaches the right level it drops then returns to the right level ever couple minutes. PO said he had it diagnosed and was told it was either a bad sending unit or another sensor under the truck. The sending unit I can see being a good guess but what could the other sensor be?

EinST

You do have a secondary fuel tank, don't you? It should be located above the spare tire. So, they probably meant the one in the secondary fuel sender assembly but that's not saying much. Is this a paid diagnosis or just talk?

Jimbos01hd

The PO said a mechanic told him about the two sensors. So maybe professional diagnoses?? I only have one fuel door and no way to swap between tanks so I'm going with only one tank.

EinST

Yours is probably a dual-tank application with one fill neck. Check for the secondary fuel tank above the spare tire. Anyway, it's not saying much since I could've said the same "could be one or the other fuel level sensors" without even looking, or even "could also be the wiring or instrument cluster."

gloft

I replaced the fuel sending unit last year and now the gas guage jumps around. Is it going bad again?

On a related subject, my engine over heated and I fixed it but the temperature guage is stuck in the hot position. Can I get it to release and work again?

EinST

Welcome to the forum. Jumps around how, from what level to what level? When the fuel sloshes around from the vehicle movement? Any noises from the rear? I think an open in the circuit would read full and vice versa, depending on the year of the vehicle. Also, I'm wondering if the baffle came loose or something.

Jimbos01hd

It will do it while driving or sitting in park. It moves up a little more each time until it reaches the "correct level"

I'll check for the second tank but when I just filled it all the way up it only took 25 gallons

EinST

Jimbos01hd, if it bothers you, you may want to get it serviced. There may be more with the issue than meets the eye.

Jimbos01hd

If I had the money to get it serviced it would definitely go in.. unfortunately times are tough.. I have taken a pay decrease every year for the last 4 yrs. so unless it would be a free diagnostic check it will have to wait to go in. While i was under it today welding the crack in the catalytic converter weld I noticed the tank said 34 gals right on the bottom yet when I filled it from 1/4 tank the other day it only took 20 gals. I do not have a second tank around the spare tire. I have to fix the P0135 and P0155 codes then figure out the P0300 code, then Ill take her in to get the gauge looked at. wasnt sure if there is any way to get it fixed at home.

gloft

Thanks Jimbo. When it's half full it jumps around when I'm sitting. No noises to speak of. Is the baffle in the tank?

Any thoughts on the frozen temp guage?