How many gallons of gas when at "reserve" marker?

[scorp508]

In my '94 I'm noticing when the fuel gauge reaches reserve, I am only able to get about 13.5 gallons of fuel into the tank. What are others seeing? My '87 with the same size tank usually accepts around 18 gallons, give or take, when it hits reserve at something like 50 miles of range to go. Unfortunately, I'm trying to fix a flashing SYS on my 94 central dash display, so I don't have access to the digital range at this time.

I've read Marc's article on heavyweight Z's, but it sounds like the issue was fixed in late '93 and subsequent cars should be able to use the whole tank.

http://www.zr1specialist.com/HAT%20W...0discovery.pdf

[Jagdpanzer]

Had a similar problem with my 94.
Solved it by pulling the sender/pump unit and enlarged the vent hole on the side of the fill pipe to 1/2". Now it fills to 18+ gallons at the gas pump without having to spoon feed the last gallon or two.


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[ghlkal]

At reserve, I can put in 17 gallons.

FWIW ... I replaced my sending unit a few years back. The new one is "non-linear" - it will show Full for a long time, and then it goes through the middle of the range "faster," but it slows down near the bottom of the scale.

[scorp508]

Originally Posted by Jagdpanzer

Had a similar problem with my 94.
Solved it by pulling the sender/pump unit and enlarged the vent hole on the side of the fill pipe to 1/2". Now it fills to 18+ gallons at the gas pump without having to spoon feed the last gallon or two.

For what it is worth I have my sending unit out due to a failed primary pump and it does not have the rubber hose on the inlet like the "heavyweight" cars Haibeck documented. I think I'll drill out the vent hole like you did and see how it goes.

Just to be clear, you are referencing this little pinhole?

IMG_8129.jpg

[Erik]

Originally Posted by scorp508

For what it is worth I have my sending unit out due to a failed primary pump and it does not have the rubber hose on the inlet like the "heavyweight" cars Haibeck documented. I think I'll drill out the vent hole like you did and see how it goes.

Just to be clear, you are referencing this little pinhole?

Attachment 20618

What are the ?heavyweight? cars?

[scorp508]

Originally Posted by Erik

What are the ?heavyweight? cars?

http://www.zr1specialist.com/HAT%20W...0discovery.htm

[Erik]

Originally Posted by scorp508

http://www.zr1specialist.com/HAT%20W...0discovery.htm

Awesome!
Thanks.

[Mr.Yuck]

Hit reserve, I put in 16.5 gallons.

[scorp508]

Originally Posted by Jagdpanzer

Had a similar problem with my 94.
Solved it by pulling the sender/pump unit and enlarged the vent hole on the side of the fill pipe to 1/2". Now it fills to 18+ gallons at the gas pump without having to spoon feed the last gallon or two.

I drilled mine out to ~3/8" when I had the sender out to swap fuel pumps. I haven't driven it enough to get to reserve and see if I'm now able to get more than 13.5 gallons in, but I did top it off and she filled nice and fast right to the top.

[scorp508]

With Phil's tip I am now able to put in ~16 gallons when I hit reserve.