2002 Silverado gas tank issues

Bill55AZ · August 23, 2005

The book says 26 gallons, and shortly after I got it, I filled up about 15 miles after the warning light came on, and it took 27 gallons. Being a cautious type, I tried to never let it get below 1/4 tank after that, but recently I did let it get close to the E mark, and this time the warning light had NOT come on. It took 27 gallons again. This is the extended cab, short bed, not the 4 door or extended cab with long bed.

I figure either there is some reserve capacity over and above the 26 gallons that they don't tell us about, or my sending unit is slowly going bad.

Anybody with similar experience?

asilverblazer · August 23, 2005

My gauge is nuts, I have a 24 gallon tank, and when the light comes on it will typically hold about 21 gallons. One time I got real close to "E" and it held 23 gallons. I go by mileage not the needle.

Bill55AZ · August 25, 2005

Costco is not likely to be messing with their pumps, so I am thinking that my sending unit is slowly going bad. One of these days I will take it to the dealership and have them test it. Meanwhile, I am going to use the trip odometer as my gas guage.

DEV1ST8R · August 25, 2005

The book says 26 gallons, and shortly after I got it, I filled up about 15 miles after the warning light came on, and it took 27 gallons. Being a cautious type, I tried to never let it get below 1/4 tank after that, but recently I did let it get close to the E mark, and this time the warning light had NOT come on. It took 27 gallons again. This is the extended cab, short bed, not the 4 door or extended cab with long bed.
I figure either there is some reserve capacity over and above the 26 gallons that they don't tell us about, or my sending unit is slowly going bad.

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I figure you've got fraudulent gasoline vendors. With the price so high, I'm surprised we're not seeing more cases of dishonest pumps.

Next time your gauge gets that low, try a different station.

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I don't buy that. . .gas stations have stricter standards than some restaurants. A fully functioning sending unit is more abnormal than a defective one, it seems. I'm in line with everybody else who has a defective fuel sending unit.

Bill55AZ · August 25, 2005

I don't buy that. . .gas stations have stricter standards than some restaurants. A fully functioning sending unit is more abnormal than a defective one, it seems. I'm in line with everybody else who has a defective fuel sending unit.

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You'll have to explain your logic to me.

How does a devective sending unit increase tank capacity? I know it didn't happen with mine.

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I think the deal here is that the sending unit is bad, making me think I have gas, but I have been very lucky and pulled up to the gas pump twice now and put in 27 gallons. The tank is 26 gallons, but there must be another gallon capacity in the fill neck or something. Anyway, I will be keeping an eye on it until a convenient time when I can get the dealer to fix it under extended warranty.

DEV1ST8R · August 25, 2005

I used to manage a gas station/car wash several years ago. . .and the same issue of getting more gallons than the tank can hold has come up several times with customers - long before gas prices took a hike. I don't know what the explanation is. I used the same pumps they used, and had no issues whatsoever. I'm sure on some applications, it has to do with the tank being overfilled, into the filling tube. And we all know, that the tank can be filled sometimes several gallons past when the pump clicks off. The only way you could be CERTAIN that the tank is filled to the absolute capacity is if you fill it until gas starts pouring out the filler. Certainly all pumps don't click off at exactly the same fill amount. All gas tanks and all gas pumps and nozzles are unique.

Gas stations are making just as much profit today as they did 5 years ago. They may be seeing volume of sales go down, but when a station buys gas wholesale, they sell it to the consumer at a set margin of profit. If the gas station gets charged .15 more cents per gallon on a delivery. . .they'll charge .15 more to the customer. If they wanted to rip us off, they'd just increase the price a couple cents to make more profit - not jack up the pumps.

Inspector's come without notice, for the sole purpose of checking for gas stations that have defective pump systems.

Sometimes the pumps do get out of calibration and go out of accuracy standards. . .maybe that's the case. Just my .02

DEV1ST8R · August 25, 2005

blacK1500, do you remember what the penalty is in your state for inaccurate dispensing volumes?

Do the regulators tend to give warnings for first offences?

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I don't know what the penalty is. On one occasion they found one of the pumps to be just OVER the standard. They tagged the pump out of service until they could come back a week later to re-check it. That gives time to correct the problem. It was good to go on the return. But I believe if it fails for the second test, the entire station is shut down. I'm not positive though.

Shawn T · August 25, 2005

GM sending units are flaky at best. I have seen them do all kinds of crazy readings. But 27 gallons? I have a friend (idiot) who ran his Silv completely out of gas about 100 feet from the gas pump (60 miles on "low fuel"). It took exactly 26.5 gallons all of the way up to the top of the filler neck. I know this because we did it for a test (so he knew the capacity). I don't think gas stations intentionally "tweek" thier flowmeters. At my power plant, our E & C shop recalibrates our flow meters (hundreds of them, even for fuel oil lines) all of the time. Even with today's high teck metering systems, they do get out of calibration from time to time. I took a 5 gallon jug to the station last week and filled it EXACTLY to the 5 gallon line and it cost me 5.5 gallons of gas. Explain that. I went home and did a water test with the tank and it took exactly 5 gallons to the line (used a 1 gallon tank filled 5 times exactly to it's line). GM guages are so bad, you almost just have to use them for a "guideline" and fill up at 1/4 of a tank.