Rebelrob

Per my Corvette black book, the fuel capacity was increased from 17 - 23.7 US gallons for the 78 year thru 82.

My gas gauge is not all that accurate. Seems to be temper-mental thru out the different seasons, outside temp etc.

Fired her up to go get fuel for this wknd.
Engine starting sputtering, figured it was a carb issue.
Rule of thumb is 200 miles max on the odometer since the rebuild then its time to fill up.
I had 168 miles when engine shut off as I pulled into the retail parking lot adjacent to the gas station. Had no idea what the problem was. Figured it could be electrical.
Long story short, I figured out I was out of gas after some carb troubleshooting and stick measurements in the tank.
From what I gathered it was almost an empty tank, I was only able to pump 22.0 gallons into the tank. Instead of 23 ish, like I figured I would be able to. I did customize the sender when I removed the electric fuel pump and put a fuel sock on the end of the fuel inlet line. Maybe its not sitting on the very bottom of tank. Just a thought. But I did match the dimensions the best I could at the time.
Could I have 1.7 gallons that is not accessible in the tank or are these tanks not all exactly the capacity they are suppose to be?
Anybody ever been able pump 23 ish gallons into one of these tanks. Or whats the most you been able add? 23 + gallons, that would assume the tank is very close to empty.
Thanks,

oldalaskaman

yes you could

hunt4cleanair

[QUOTE=Rebelrob;1580958957]Could I have 1.7 gallons that is not accessible in the tank or are these tanks not all exactly the capacity they are suppose to be?[/quote]

I agree with all that was said by the old alaskan.

[QUOTE]Anybody ever been able pump 23 ish gallons into one of these tanks. Or whats the most you been able add? 23 + gallons, that would assume the tank is very close to empty.
Thanks,[/QUOTE]

I've attempted to run my 78 dry as well just to test how much is in reserve. It was a while ago but here's my recollection which while not as accurate as what you've done...approximates similar results.

I concluded that there are five gallons in reserve where I determined reserve is when the light comes on (LOW FUEL) and seems the needle is on E..the red portion. I than ran it until the needle dropped below the E line (black) than decided it was time to get fuel. Seems it took 21-22 gallons and I believe 22 was the highest I've ever put into with fuel still remaining.

At the moment, the needle on the gauge is sitting near E but the LOW FUEL light has yet to come on. I rarely fill up so I may not be able to test it again.

Hope this helps!

damoroso

Rob, I've put 21 gals before, nearly 22 but that's it, and the light was on.

How's it run'n now???

Easy Mike

I've put 20-21 gallons in my 80 but I always try not to run it that low. I cannot recall a 22 or 23 gallon fill.

gbvette62

Chevrolet advertised the 78-82 tanks as 24 gallon, but I've always thought that that was a little optimistic! I don't think that I've ever gotten more than 22 gallons in my 81, but I've also never tried to run out either.

Prior to the mid 90's, when there were a number of class action lawsuits against the automakers over such things as advertised capacities, tank size was often rounded up to the next whole gallon.

Those tanks all had a plastic liner (or bladder), in them. I wonder if the 24 gallons was the total capacity of the tank, without the liner. The liner would obviously reduce the overall capacity slightly.

Obviously, how much gas you get out of the tank, is going to be effected by the position of the pick up.

The liner can cause a problem with these tanks, too. Some liners have been known to leak. When this happens, fuel gets trapped between the liner and the tank. The fuel is obviously in the tank, and the gauge will read correctly. What happens then, is that you'll get down to an indicated half or quarter tank, and run out of gas! The gas is in the tank still, but the pick up can't get it, because it's outside of the liner.

den(thevetteman)78

Do all '78 have a red light low fuel ? Because i ran out of fuel once and the light never came on. I see where it should be but never saw that light on.

~Stingray

Without looking anything up, I thought these cars had 16-18 gallon tanks. Whenever I get to half a tank, I am only able to put about 8-9 gallons in.

oldalaskaman

change the bulb

gbvette62

All 78-82 Corvettes used the same 24 gallon tank. You may be experiencing the situation I spoke about in my earlier post, where the bladder leaks and fuel gets trapped between the liner and the tank.

Below is the Dimensions and Specifications page from the Corvette section of the 1980 Chevrolet Dealers Album. The fuel tank capacity is on the next to last line.

Rebelrob

Good info guys. Now that I think about it. My DD advertises a 18.5 gallon tank and I have run that thing till its past E on the gauge and the most I have ever been able to pump into it is 17.25 gallons.

gbvette62, I read a bunch of other threads about the whole tank bladder/liner. That seems to be an issue in most of the 77's and earlier models. From what I read there is not a so called bladder in 78-82's. The tank is some sort of plastic type fuel cell wrapped with steel. Grumpy427 had his out and he did some repairs. I also had my sending unit out of my tank a while back when I made my mods to the pick up and did not feel or see a bladder. Here is his thread. Interesting.
http://forums.corvetteforum.com/c3-g...nk-repair.html

My fuel light does not work also. My gas gauge seems to only be accurate at certain times of the year.... go figure...
The only concern I have is my second engine rebuild, maybe gets worse gas mileage than the first one. But then again, I had the timing more retarded for the first 50-60 miles.

Edit: Pic of my sending unit/pick up before I modded it and removed the fuel pump. This is the angle it sits in the tank. So with the bend the pick is towards the upper end of the tank not the back bottom. So maybe the last gallon or so in the tank could never be reached by the pickup.

[IMG]http://[/IMG]

den(thevetteman)78

I just change the bulb and nothing. Does it light up when the ignition is on like all the other lights because nothing light up. Could it be the small circuit board ? My tank is real empty so it should be on now.

'75

Probably the little circuit board bad. I see on fle-bay, someone is selling new ones.

RaptorTest

Willcox can repair the circuit board. Costs around $50. With the key in ACC or ON, ground the sensor wire coming from the tank sendor. That'll force the gauge to empty. Count to 30 or so and the light should come on (it has a delay). If it doesn't and you've checked the bulb, circuit board is probably bad.

terry82

i have read of several guys with 82s that when the fuel is low and they take a turn the car sputers .add gas and the car is fine .i think its the pick up.

mds3013

The low fuel module is the normal cause of the Low Fuel light not coming on when it should. They are easily repairable if you want to try. Ck. this thread for testing info. I will try to find the repair thread. mike...


http://willcoxcorvette.com/instructi...RNING_LAMP.jpg

http://forums.corvetteforum.com/c3-t...77-1982-a.html

http://forums.corvetteforum.com/c3-t...ng-module.html

BKarol

Just a FYI, the owner's manual reads that the Low Fuel Indicator Light will glow when level has dropped to approximately 2 gallons.

...Roger...

I notice the fuel inlet hangs down around 3",wonder how much of an air space that creates at the top of the tank ?
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