So I just got an 04 Z06 and I came across something today that some of the seasoned c5 owners could shed some light on

I know the DIC reserve fuel light comes on based on your most recent avg. mpg

Mine came on today reading ~50 miles left, when I hit about ~30 miles left the gauge on the dash was all the way to the left deep in the red.

Is this normal or could my car be reading wrong

 

normal

i actually ran out of gas on purpose and it took about 20 miles or so (normal street driving) to completly stall out.. after u see the needle just past the last bar ( alsmot negative)

 

thank you I was getting paranoid, I wanted to wait for a better gas station but I got scared and filled up at the first place I saw

 

NEVER trust your gauge or DIC on fuel! Keep it 1/8th or better! Each car is different!


My $00.02

 

MUKAK, why would you purposely run out of gas? That's pretty bad for your fuel pump.

 

I've noticed in my car if I run it down to 1/8 and shut the car off, when I start the car back up it will go all the way to empty.

Now I'm boosted so I don't let my fuel get that low

 

There are two functions; one fixed depending on the contents and the other dynamic.

I was hazy on the detail so I checked the manual. It says "When the needle approaches the red zone, RESERVE FUEL will appear on the Driver Information Center (DIC) display. When the needle approaches the E, LOW FUEL will appear on the display".

In the range mode on the DIC:
The range calculates the remaining distance you can drive without refueling. It’s based on fuel economy and the fuel remaining in the tank.
If the range is lower than 30 miles (48 km), the display will read RANGE LOW".

I've never seen Low displayed but I saw Reserve once and it came on at about 60 miles to empty. I try to top off at 1/4 full to make sure no rubbish is fed from the tanks.
HTH

 

It is my understanding that the fuel sending unit is relying on some fuel to keep it cool. Our mechanic says that running any new car below 1/8 tank is tempting fate and an expensive fix. It's simple enough thing to keep that much gas in the tank, whether he's right or wrong.

 

Same thing I've heard about letting the gas get too low.

 

You're correct as far the fuel pump being submerged in fuel to assist in cooling, but the electric fuel pump itself (which is what you're speaking of, not the sender) is enclosed in a container or "bucket", specifically to keep it submersed when the tank levels are low.

I agree with you as far as keeping fuel in the tank, but I prefer to do it because it minimizes any water (from condensation) in the tank. One other nice thing about plastic tanks too is that they "sweat" less than metal tanks, which also reduces water.

 

Based on the 1/8th rule, how many gallons then does it take to fill up the tank(s)? We all the know the fun of filling our C5 tanks and the fact that most gas pumps click off due to the angle, so I monitor my gallons dispensed while filling up.

 

Both tanks in total is about 18 US gallons. Mine fills normally. There's a TSB out for a fix to the slow fill problem. It replaces the pipe just behind the gas cap.

Vehicle is Difficult to Fill with Fuel or Filling Station Pump Shuts Off Before Tank is Full (Replace Tank Filler Hose) #04-06-04-031 - (Apr 22, 2004)
Vehicle is Difficult to Fill with Fuel or Filling Station Pump Shuts Off Before Tank is Full (Replace Fuel Tank Filler Hose)

1997-2004 Chevrolet Corvette
Condition

Some customers may comment that their vehicle is difficult to fill with fuel or when filling, the pump continuously shuts off before the tank is full.
Cause

This condition may be caused by back pressure within the fuel filler hose. This back pressure trips the fuel nozzle prior to filling the tank, or results in a hard to fill condition.
Correction

Replace the fuel tank filler hose with P/N 10353139. This new hose has been redesigned to provide smoother flow conditions within the section. Use the procedure listed below.

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in the General Information sub-section of the Service Manual.
2. Remove the left rear tire and wheel.
3. Remove the left rear wheelhouse panel.
4. Loosen the lower hose clamp through access hole in body using ¼ drive ratchet and extension.
5. Loosen the upper hose clamp.
6. Remove the fuel tank filler hose.
7. Install the new fuel tank filler hose.
8. Tighten the upper hose clamp.
Tighten

Tighten the fuel filler hose clamp to 4N•m(35 lb in).
9. Tighten the lower hose clamp through access hole in body using ¼ drive ratchet and extension.
Tighten

Tighten the fuel filler hose clamp to 4N•m(35 lb in).
10. Install the left rear wheelhouse panel.
11. Install the left rear tire and wheel.
12. Lower the vehicle.

Parts Information

Part Number


Description

10353139


Hose, Fuel FillerVehicle is Difficult to Fill with Fuel or Filling Station Pump Shuts Off Before Tank is Full (Replace Tank Filler Hose) #04-06-04-031 - (Apr 22, 2004)

Vehicle is Difficult to Fill with Fuel or Filling Station Pump Shuts Off Before Tank is Full (Replace Fuel Tank Filler Hose)

1997-2004 Chevrolet Corvette

Condition: Some customers may comment that their vehicle is difficult to fill with fuel or when filling, the pump continuously shuts off before the tank is full.

Cause: This condition may be caused by back pressure within the fuel filler hose. This back pressure trips the fuel nozzle prior to filling the tank, or results in a hard to fill condition.

Correction: Replace the fuel tank filler hose with P/N 10353139. This new hose has been redesigned to provide smoother flow conditions within the section.

Use the procedure listed below.

1. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in the General Information sub-section of the Service Manual.
2. Remove the left rear tire and wheel.
3. Remove the left rear wheelhouse panel.
4. Loosen the lower hose clamp through access hole in body using ¼ drive ratchet and extension.
5. Loosen the upper hose clamp.
6. Remove the fuel tank filler hose.
7. Install the new fuel tank filler hose.
8. Tighten the upper hose clamp.

Tighten

Tighten the fuel filler hose clamp to 4N•m(35 lb in).
9. Tighten the lower hose clamp through access hole in body using ¼ drive ratchet and extension.

Tighten

Tighten the fuel filler hose clamp to 4N•m(35 lb in).
10. Install the left rear wheelhouse panel.
11. Install the left rear tire and wheel.
12. Lower the vehicle.

Parts Information

Part Number: 10353139

Description: Hose, Fuel Filler

Heres a pic of the fuel filler pipe that may help

 

Thanks! Was that repair sent out as a recall or would we have to pay for it if the car is out of warranty?

Regarding the 1/8 rule, since the fuel capacity is 18 gallons inclusive of the reserve fuel, a fill up would be between 15 and 16 gallons once the needle hits the 1/8th mark.

 

A Tech Service Bulletin is just to document the fix. It wasn't a recall to the best of my knowledge as there's no safety implication. I guess it would be at owners expense now.

The math looks good to me

 

I was able to drive about 50 miles once my fuel light came on. I fell just short of the 18 gallon mark so I probably still had another 15 or so miles until empty.

By the way, it's bad juju to run your car all the way to empty.

 

If I fill up and then reset the DIC to 0 mpg, it will momentarily display range low. I guess it is saying, at 0 mpg, even with 20 gallons, you have 0 miles to go.

 

 

Reserve is 3gal, main fuel tanks are 15gal.

 

While the fuel pump unit is housed in a plastic "cage" the pump motor itself sits above the fuel pickup.The tech was absolutely right in saying that running your fuel that low can affect the pump.I think you would have to be one of those who does it constantly though.

 

That makes sense. I saw reserve at 60 miles. My average mpg is about 20 around town so 3 gals is about right.