Fuel gauge off

[07stuntin6r]

So newly owned Car and I'm pretty sure the gauge is faulty. Filled her up and its reading wayyyy past full. Car shows 1/4 of tank when actually empty. How can I fix this prob? (I'm horrible with wiring and colorblind;))

[Injuneer]

Common "problem" due to shape of tank. Not really fixable. You just have to allow for the fact that when it's 1/4-tank, you better fill it up ASAP.

Shoebox documented this about 15 years ago, and it matches what I figured out within a few months of buying my Formula brand new in 1994:

http://shbox.com/1/4th_gen_tech2.html#fuel_gauge

[Fastbird]

Ditto. The tank is triangular, with the narrow point being at the bottom. So it normally will show way past full and hang there for a while then drop like a rock, and at 1/4 tank it's sweating time if you're not in sight of a gas station.

I've been trying to figure out if there's a programmable resistance box that you could install in-line with the sender wiring, then manually program actual levels based off of resistance by taking measurements at the sender for the various levels, interpolating the gaps, and programming for compensation. It's GOT to be doable with all the electronic wizardry we have today.

[popo8]

Im confused...do u mean in am fbody? Mine are both dead on...the camaro was messed up...so we pulled it...made sure the float was moving...then back to normal.

[Injuneer]

I've seen HUNDREDS of people with the same complaint on a 1/2-dozen 4th Gen forums over the 15 years I've been active on them. Mine was so obviously wrong that I created my own calibration chart. It was actually pretty easy.... above Full to Full was 4 gallons. Full to 1/2 was 6 gallons, so a total of 10 gallons had been used, and only 5.5 left at the 1/2 mark. When the needle hit exactly 1/2 you mentally divided the miles on the trip odometer by 10, and it gave you your miles/gallon with amazing accuracy. From 1/2 to 1/4 was 4 gallons, leaving only 1.5 gallons at the 1/4 mark..... FILL 'ER UP.

The gauge also responded to braking and acceleration by increasing and decreasing the indicated level, and also responded to left and right turns going up on one side and down on the other.... can't remember at this point which way was which... but then the car never has more than 4 gallons of fuel in it now.

Engineers are obsessively anal with numbers..... :D :D :D . You'd think we had nothing better to do.

[popo8]

Did u ever just pull it out and mess with the float and watch the guage as its connected...but out. Slight bends and u can get it pretty accurate.

[Fastbird]

Larry this is a VERY common issue. That you're not familiar with it shocks me. If your Camaro is truly dead on I'd be astounded. Not doubting you, just never seen it. Even the showroom 99 Trans Am I bought was not right,

Posted from my LG G2

[07stuntin6r]

Jeeze that sucks lol pretty annoying!!!

[popo8]

My trans am is DEAD nuts on..the camaro is pretty damn close... honest.

[popo8]

But like I said...the camaro required pulling everything..leaving it plugged in electically..and workin the float and watching the guage till it matched...

[popo8]

Soooo. BE ASTOUNDED!

[popo8]

Soooo. BE ASTOUNDED!

And yes... I am familiar with the issue complaints...just dont understand why people just accepted it.

[07stuntin6r]

Sounds like a lot of work tho. If I had it off I would do it.

[Spartan7]

I've been trying to figure out if there's a programmable resistance box that you could install in-line with the sender wiring, then manually program actual levels based off of resistance by taking measurements at the sender for the various levels, interpolating the gaps, and programming for compensation. It's GOT to be doable with all the electronic wizardry we have today.

I've had the same thought. If someone came up with a box to calibrate the resistance signal so the gauge is actually accurate and linear, it would be a big seller.

OP, if you run the tank near empty, you can pop the fuel needle off the cluster and push it back on where "E" is, that will at least be accurate. But no amount of tweaking the float arm will fix the non-linear way the gauge drops after "1/2" tank. I usually try to fill up around 3/8 of a tank.

[SJx408]

Luckily my Camaro has a pretty accurate reading. Definitely seen the other fbody cars with empty tanks at the 1/4 line. I would just make a mental note and start filling when it got below 1/2. I try and roll on full all the time anyways.

[Injuneer]

Once you've mentally corrected it, it's not annoying at all. It's totally predictable, and repeatable.