Anyone else's gas gauge ever do this?

ga_etc · #1 (**permalink**) 10-24-09, 12:50 AM

I went to Chattanooga this afternoon to see a movie with a friend. When I left the house I had just under a quarter tank of gas. I knew I would be pushing it but I could go there and back without having to stop and fill up. It's about a 50 mile round trip. Well on the way home coming back down the interstate I noticed that my gas hand was RISING.

By the time I got back to the grocery store up from my house the gauge was up to about 2/3. When I started off again, the hand started rising again, only faster now. From the store back to the house, about 2 miles, it was pegged out at full. I parked in the driveway, level, the gauge dropped around 1/4 then right back to full.

While filling up I turned the switch on to see how the gauge responded. It was working as normal. So, I'm hoping that this was a one time freak occurrence. Anyone have any ideas what may have caused it?

eyekandyboats.inc · #2 (**permalink**) 10-24-09, 01:03 AM

you need a fuel sending unit, quite common, use the search feature and type in "fuel sender" and you will get a boat load of info.

ga_etc · #3 (**permalink**) 10-24-09, 01:08 AM

It was working properly when I filled it up. I guess I will just have to drive it and see how it does.

maeng9981 · #4 (**permalink**) 10-24-09, 01:18 AM

Don't drive too long with malfunctioning sending unit. If you run out of gas, you will have a chance to fry your fuel pump. Fuel pump is cooled down by gas.

My 99 deville has a bad fuel sending unit. it stays at full almost all the time and sometimes between 15~18. I just drive it until it hits 200 mile trip after fill up. Then I go to gas station and get full tank.

The tank is 18.5 gallon I believe, so unless you are getting below 15 mpg all the time, it should go more than 250 miles per one tank.

ga_etc · #5 (**permalink**) 10-24-09, 01:25 AM

The tank size on the Eldorados is 20 gallon. Unless I'm under more strenuous driving conditions I can go 300 on a tank.

00 Deville · #6 (**permalink**) 10-24-09, 01:35 AM

Keep a close eye on it. Sounds like the sending unit is on its way out like the kandy man said. An open on the sending unit will cause it to read full a short will cause it to read empty.

ga_etc · #7 (**permalink**) 10-24-09, 01:42 AM

Any chance that will trip a code to confirm it?

00 Deville · #8 (**permalink**) 10-24-09, 01:46 AM

It is possible that it will trip a code.

It's been covered on here a bunch of times... every crazy acting gas gauge thread I've seen on here was the sending unit. Just keep an eye on it if it acts up again you will know whats causing it.

ga_etc · #9 (**permalink**) 10-24-09, 01:48 AM

Ok. Any idea what that might cost to repair?

00 Deville · #10 (**permalink**) 10-24-09, 02:02 AM

It can trip a code..... would be a P0461 or 62 or 63

The sensor is $114 at RockAuto.com

ga_etc · #11 (**permalink**) 10-24-09, 02:13 AM

Pulled the codes and found this: B0533 - Fuel Sensor Open/Shorted To B+

00 Deville · #12 (**permalink**) 10-24-09, 02:23 AM

Was it current or history?

ga_etc · #13 (**permalink**) 10-24-09, 02:24 AM

History. I had started it a couple of times.

00 Deville · #14 (**permalink**) 10-24-09, 02:31 AM

Good... The FSM states that if it's a history code replace the fuel sending unit. Unfortunately I believe your 99 Eldo requires that the fuel tank be dropped to change the sensor. So you want the tank fairly empty to make it an easier job. The latter model Caddys' have an access plate in the trunk to access the pump and sensor.

ga_etc · #15 (**permalink**) 10-24-09, 02:44 AM

I know a guy that has a shop in town so I'll give him a call tomorrow and see what it might cost to have that replaced. Hopefully not too bad since I need to have the coolant changed as well. It's always something I guess...