Stuck gas gauge (full)

[RedDragonATL]

So, I went off-roading today and as I'm leaving the park, I notice my gas gauge is reading full. I thought maybe the float was stuck at the top and refilling would dislodge it. No luck. I DID search on stuck gas gauge and stuck fuel gauge and found some posts saying there are "issues" with the gas gauge, but didn't see anything like my situation. It does go down without power obviously, but is stuck on Full under power. Any thoughts?

 

[Rwperlaki]

If I remember right when a gas gauge sticks on full its a bad ground. When a gas gauge sticks on empty its ither a bad sending unit or a bad positive wire. I would find out where the ground wire for the sending unit runs and check it out. You might have tore it out or it came lose wile off roading.

 

[J-money$$$]

smashed gas tank and bent sending unit? I dont know if you were really wheeling hard, but if you were crushing the tank then that can happen

 

[RedDragonATL]

Both good thoughts. Yeah, I was banging it pretty good. Sounds like I need to go check the tank! I've just got the stock tank skid on, and it already had a little dent.

 

[RedDragonATL]

Ok, so the tank skid (and I'm assuming the tank) have a nice V-shaped dent down the length. Didn't realize I was beating on it quite that hard. I think it was a big pile of rocks we went over. Am about to drop the skid and see what the tank looks like. Will post some pics.

 

[jonwilly2]

my tank is 16 gallons now.

 

[RedDragonATL]

Yeah, it's bent.

 

[J-money$$$]

there ya go. These things bend pretty easily

 

[RedDragonATL]

OK, well I finally got around this past weekend to dropping the tank and removing the fuel pump and sender unit. The fuel pump "arm" was definitely bent, but didn't see any damage to the fuel sender unit.

So, I tested the fuel sender and it "seems" to be working correctly...it runs from about 190 (empty) and 18 (full). I think it's supposed to be 180 to 10 ohms, but close enough.

So, I took off the fuel pump and straightened the "arm" back out and then replaced the pump.

I haven't put it all back together, but do you think there's anything else I should look at before I do? Should I try and push the bottom of the tank back out?

All of the connections seemed to be good. It was a PITA to get drained and off, so I don't really want to do it again if I can help it. Thanks in advance for any other suggestions.

 

[RedDragonATL]

Just to be clear, I didn't put a new fuel pump in, just put back the one that was there after I straightened everything out.

 

[RedDragonATL]

No suggestions??

 

[LittleCaesar]

I am one of those guys that if I went through the trouble of dropping the tank, I'd replace the sender, heck probably even the pump itself.

Having dropped about 12 tanks in my life, it ranks up there as just plain miserable. I hate gas.

 

[RedDragonATL]

Yeah, I've been huffing fumes for a few days now...no fun. Well, I just did a test with the fuel pump/sender assembly still apart from the tank, and the gauge is operating again. Maybe the twisted fuel pump arm wedged the sender float arm against the side of the tank, or somehow caused it to short out. I think I am going to just hope for the best and put it all back together tonight. I will post back when I'm done.

 

[RedDragonATL]

I am one of those guys that if I went through the trouble of dropping the tank, I'd replace the sender, heck probably even the pump itself.

Having dropped about 12 tanks in my life, it ranks up there as just plain miserable. I hate gas.

Hey, LittleCaesar, do you know if the fuel sender unit is supposed to have a cover on the back, where the wired connect? Mine doesn't, but seems like it should.

I had to bang out some if the dent in the tank to get the assembly to fit back in there. It's pretty tight.

So, I got the assembly back in the tank and jacked it up under the truck. I hooked up the wiring, but got the same false full reading. Dropped the tank again, pulled the assembly and tested it again outside the tank. Works. So, I'm thinking maybe the sender unit is pressing against something in there, so I bend the arm slightly to pull it "in". Put it back in, jacked it up and it "seems" to be working. Then, it started raining harder and I had to come in. I will connect the fuel lines & hoses back up tomorrow and see if it's still ok. Not feeling great about this as a long-term fix, though.

 

[LittleCaesar]

RDATL,

I don't know. I have seen some weird internal fuel pumps and senders, almost as if the engineers threw darts at the design and guessed what would work.

So it looks as if that dent on the fuel tank was indeed your problem. If you don't want to spend the money on a new one, run the gas through and see if it read as accurate or close to what it was reading before.

You may want to start a new thread with the topic as "Is this what your fuel sender looked like" as the title and for those who have done it, maybe one will reply.

 

[RedDragonATL]

Well, I had my hopes up...

After I put it all back together, the gauge was showing empty and the gas light was on. After I put the two gas cans back in that I siphoned out, it was just below 1/4 tank. So, it appeared like it was working.

But, I filled it up tonight and it stayed about 1/4 tank. So, maybe the float can't travel all the way up. Who knows? Ugh. I'm going to leave it for awhile, I think.

I will post back up here when/if I tackle it again.

 

[RedDragonATL]

Well, I went off-roading again this past weekend over in Alabama (R.I.P. MSORP, btw) and I smashed my tank some more, and lo and behold, as I'm leaving the park, I notice that the gauge is stuck on full again. So, here we go again. I have found some local used gas tanks for $75, so I think I am going to pick up one of those and also go ahead and get the Lil Skip gas tank skid to beef up my protection. Not sure if my fuel sender is damaged or not...I will try and re-use my existing one and see what happens.

I will keep you posted!

 

[Nelsonmd]

I think I am going to pick up one of those and also go ahead and get the Lil Skip gas tank skid to beef up my protection.

Uhhh, yeah. Good call.

 

[ChildrenOfBodom]

I would quit wasting your time with the sender unit. 99-00 are notorious for this problem and they do have a TSB for it.

Here's what I did:
11-05-2011, 11:40 PM: New fuel sender unit and gauge cluster motherboard to fix the fuel gauge


Fuel gauge working beautifully since.

 

[Mellow77]

I am one of those guys that if I went through the trouble of dropping the tank, I'd replace the sender, heck probably even the pump itself.

:thumb3: I'm the "while it's apart" guy...I would be finding a F150 or larger tank upgrade to stick back in it's place now that you've completely taken it apart.