Need help. After I filled up one day, the gauge read full and went past full. Then about a week later it still read full and its been like that since. It's only the gas gauge that isn't reading properly, and I was wondering if anyone had any ideas for what to check first. Thanks.

 

sounds like your float in the tank is stuck or your sending unit went out ...

 

The problem is GM made a crappy gas measurement system.
iether your tank sending unit or your gauge can cause this.
Mine for example will sometimes read correctly when i am below a quarter tank, but it will never read correctly anywhere else.

use your odomeder to tell what is in your tank. it is always more accurate than your tank. unless you idle in the parking lot everyday.

 

what's the easiest way to get to the tank sending unit? and if that's the problem, where do you get the replacement?

 

The search function here will retrieve the many posts on this topic generated as our cars pass into the 200,000-300,000 accumulated mileage areas.

Easiest way to get to the sending unit -- have a garage do it for $600-1,200 labor. The garage can get the replacement from GM for about $400.

Shocking isn't it!

If those are not favorable options for you, read on.

Be forwarned you are now entering the "Flaming Fuel Tank Twilight Zone," slip on your firesuit, gulp some Prozacs and air -- the Loony-Tunes will slice and dice with "if you do this you're dumb and if you do that you're dumber," bile. Anyway, here we go...

Here's my experiences of working through the tank sending unit and fuel pump replacement issues on both my '92 and '87 Camaros.

First, with the ignition key on, tap on the gauge, sometimes the indicator needle sticks at the top of the sweep when the electronics are first switched on. Check the sending unit output at the weatherpack tank connection.

If the gauge is good and sending unit dead, you then have several choices:

1. Live with it and use your odometer and average fuel mileage to gas-up, when say 75% of the tank is empty. I did this for a number of years based on my 5.7 getting 20 mpg around town so every 200 miles I put in 10 galllons of gas.

2. Drop the fuel tank and replace the sending unit. Replacements are available used for about $50-75 in the classifieds or on auctions. I have bought three this way in my quest to re-engineer GM's design oversight. If you're handy with workin on your car, JC Whitney has a add-on generic 0-90 ohm sending unit costing about $25 that can be used to replace the GM factory one with a bit of fabrication. The sending unit from GM costs about $300, yeah really! Dropping the tank yourself is not difficult unless you're on the side of the road somewhere in the middle of Death Valley with all your belongings in the car. How hard is to drop the tank? Some will tell you they did it in two hours from their wheelchairs using only one hand most of the time. Yeah, it's not hard if you have a lift and someone to help wrestle the tank in and out [bend the neck and you'll wanna snuff yourself trying to get it back in, heh]. GM will do this job for only $1,500 or more, I have the receipt to prove it. Other garages will ding you for about half. GM provided a lifetime parts/labor warranty on the fuel pump, so next time GM does the dirty work on my '92.

3. Cut an access panel in the hatch area over the fuel pump area of the tank and modify the system to change the fuel delivery system to swap out those parts in about 20 minutes without going under the car. I did this on my '87 to prevent someday being towed to a garage when the pump dies 600 miles outside of Bumsville four states away.

You have to make your own choice based on your circumstances.

Here's a good [and slug-fest locked] link with what you need to know about tank-work.

"Going to do the backdoor fuel pump install..."

https://www.thirdgen.org/techbb2/sho...hreadid=264787

 

If you can stand the down time, contact Year One, they have/had a service to recalibrate your gauge & sender. Take them both out and send them to Year One and wait.

 

dropping the tank in your car isnt that difficult you can accomplish this with a buddy and hand tools in about 4 hours start to finish ...

 

Here's a 3-view from Trickster showing the components of the fuel tank sending unit and pump. If your sending unit is bad and you opt to buy a used replacement, make sure the seller guarantees the 0-90 ohm capsule works ok. Sometimes sellers will try to send units that have been salvaged from cars totaled in accidents with damaged delicate sensor contacts or resistance wire.

 

Hit your ****ing dash board. Right on the guage, with some force. My temp and gas guages both stick. Go ahead, don't be shy!