2011 Silverado 5.3L Refueling Issues - HELP

zbyler · January 30, 2016

Hello all,

Let me start by saying that I've read countless threads on Silverado re-fueling issues, but the issue I'm experiencing seems to be quite different from anything that I've read. I've tried a few different solutions but nothing has helped thus far. I'm hoping the forum members here will be able to provide further insight into what the hell is going on.

Problem:

I have a 2011 Silverado 1500 with the 5.3L engine. A few months ago, I started experiencing problems when re-fueling. More specifically, the gas pump would shut off when roughly 15 gallons of gas had been added. To be clear, the pump would allow me to put in around 15 gallons at normal speed with no issues. Please note that I have a 25 gallon gas tank and I typically refuel when the gas gauge is just above the E line (or when the light comes on). After the pump would initially shut off, I would squeeze the pump handle again to try and add more gas, but it would just shut off after a few cents worth were added.

Please note that prior to experiencing these issues, I have never attempted to "top off" my gas tank after the pump shut off. I have read that this could cause problems with the Evap solenoid, etc, but this is not a habit that I condone or practice.

Solutions Attempted:

I started with the easiest solutions -The first thing I tried to do was to slightly remove the gas nozzle from the tank. I also tried rotating the nozzle slightly to see if that made a difference but each idea had no affect and the pump would continue to shut off after a few cents.

I had read about people attempting to syphon gas from trucks and items breaking off in the gas tank neck so the next thing I tried was taking a flashlight and looking down in the tank neck to see if I could spot anything. The neck was clear.

Almost all of the forum threads I read mentioned replacement of the evap solenoid as a possible solution for this issue. I ordered a brand new evap solenoid assembly (complete with lines and filter unit) from AC Delco and installed it. I drove the truck down to the gas station to try and fill up and it did the exact same thing and shut off right around 15 gallons. Really?! This made me think that maybe the gas gauge was reading incorrectly but the gauge read about 3/4 full consistently after every 15 gallon fill up. I was also able to add more gas to the tank using a spare gas can so I know there is room to add more gas than what it will currently take.

Next Steps:

Moving forward, I'm thinking this could be a fuel pump issue of some kind, possibly the fuel level sensor? This issue is more of just an inconvenience at this point but I'm meticulous with my vehicles and when things are wrong with them, I like to get to the bottom of it and get them running 100% as soon as possible. Before I resort to taking it to the dealership, I'm hoping someone on here can chime in with some other ideas.

Any help is much appreciated! Thanks in advance.

GeorgiaBII · January 30, 2016

It's not going to be a sensor or fuel pump issue. You have a vent tube issue. There is a smaller hose that allows the air to vent from the tank as you fill it. It's either plugged or damaged would be my guess.

Start there.

zbyler · January 31, 2016

It's not going to be a sensor or fuel pump issue. You have a vent tube issue. There is a smaller hose that allows the air to vent from the tank as you fill it. It's either plugged or damaged would be my guess.

Start there.

GeorgiaBll, thanks for the response. I believe you're talking about the line that comes directly off the filler neck, correct?

As I mentioned, I replaced the evap solenoid assembly which comes off the opposite side of the gas tank, but I didn't think about checking farther up stream at the filler neck. I'm gonna run outside and see what I can find before it gets dark.

Thanks for the input!

GeorgiaBII · January 31, 2016

Hope that helps you. Is the first thing that came to mind with that issue.

zbyler · January 31, 2016

Hope that helps you. Is the first thing that came to mind with that issue.

GB, I spent some time checking out the vent line from the filler neck earlier this afternoon. Here's what I found:

1. Theres only 1 line coming off the filler neck so I'm assuming this is the vent line in question. I followed the line to see if there were any kinks or damage, there wasn't:

2. I removed the worm clamp holding the vent line to the elbow coming off the filler neck to look inside. There seems to be a metal inner lining of the hose so I couldn't really see much:

3. I followed the vent line to the termination on the top of the fuel pump. I couldn't get my hands up above the tank to release the clip though.

Since the evap solenoid is brand new it's unlikely that it's malfunctioning but I checked all of the lines just to be sure. No issues there.

I'm still leaning towards the fuel level sensor for being the cause..........

GeorgiaBII · January 31, 2016

I would blow through it to be sure it's not clogged.

Wish you luck!

zbyler · February 2, 2016

I would blow through it to be sure it's not clogged.

Wish you luck!

Unfortunately, with the gas tank in place, I can't get my hands on top of the fuel pump to reach the other side of the vent tube to unclip it.

What happens if I remove the end of the vent hose from the filler neck and then try to fill the truck with gas? If this works, then I can assume the vent line is clogged, correct?

diyer2 · February 2, 2016

I would not run my gas tank so low all the time, you're losing fuel pump lubrication and cooling by doing this that's what the gas does.

Have you checked mileage and fuel by hand to see if the gauge is wacky?

zbyler · February 3, 2016

I would not run my gas tank so low all the time, you're losing fuel pump lubrication and cooling by doing this that's what the gas does.

Have you checked mileage and fuel by hand to see if the gauge is wacky?

Diyer,

You're absolutely right, I really shouldn't run my tank so low, but it's always been a bad habit of mine. I try to catch it around 1/4 tank if I can.

I have checked the mileage by hand and everything seems to be accurate.

Another thing to consider: If the cause really is the fuel level sensor, wouldn't I have experienced inconsistent readings from the gas gauge such as noticeably false readings and random increases and decreases? Right now it functions like normal, other than the fact that it won't go above the 3/4 mark when the pump shuts off.

diyer2 · February 4, 2016

If I got this right, you've owned the truck for a while and this problem started recently?

Try this, a PITA (pain in the a$$) I know.

Let it fill like you have been until it shuts off. Take it for a short drive, then stop and see if it will take more fuel. If it does I think it's getting an air bubble or vapor lock.

zbyler · February 15, 2016

If I got this right, you've owned the truck for a while and this problem started recently?

Try this, a PITA (pain in the a$$) I know.

Let it fill like you have been until it shuts off. Take it for a short drive, then stop and see if it will take more fuel. If it does I think it's getting an air bubble or vapor lock.

I've owned the truck for about 2.5 years and this problem only started recently, specifically after my truck was rear ended at a red light.

I tried your idea and the pump shut off almost immediately the second time I tried filling it. Still stumped on this issue.......

muddkatt · February 17, 2016

I've owned the truck for about 2.5 years and this problem only started recently, specifically after my truck was rear ended at a red light.

The accident might have caused the float on the fuel pump assembly to get out of tolerance. How many miles are on the truck/fuel pump?

zbyler · February 17, 2016

The accident might have caused the float on the fuel pump assembly to get out of tolerance. How many miles are on the truck/fuel pump?

Muddkatt,

Excellent point. The truck has roughly 55k miles on it. Original fuel pump.

I've ordered the fuel level sensor and will be installing it on friday afternoon. I'll be taking a very close look at the entire fuel pump assembly, all connections, and the gas tank during this time.

muddkatt · February 17, 2016

My 2001 had the fuel pump replaced at about 50K miles due to the gauge readings being way off. Don't remember if it was showing real low or high. Since then I have had to put a couple of pump assemblies on it. FREE ADVICE: don't buy aftermarket pumps from Auto Zone, etc...buy AC Delco.

Easy way to change them is removing the bed, unless you have access to a shop with a lift and transmission jack.

zbyler · February 17, 2016

My 2001 had the fuel pump replaced at about 50K miles due to the gauge readings being way off. Don't remember if it was showing real low or high. Since then I have had to put a couple of pump assemblies on it. FREE ADVICE: don't buy aftermarket pumps from Auto Zone, etc...buy AC Delco.

Easy way to change them is removing the bed, unless you have access to a shop with a lift and transmission jack.

If replacing the level sensor doesn't work I'll be purchasing and installing a new ACDelco fuel pump.

Do you think removing the bed is easier than dropping the tank? I don't have access to a lift and there isn't much room in the garage I'll be using. I was planning to drop the tank from below.