2005 Escalade ESV Gas Filling Issue

[bajajoaquin]

I've got a 2005 Escalade ESV with 147k on it. It's fairly new to me. One issue I'm having is that either my gas gauge is miscalibrated and it reads that my tank is about half full when it's really full, or there's an issue with the filler neck/vent system preventing me from filling it. Given some of the issues and recent changes, I now suspect the filler neck/vent. Symptoms:

I've never been able to fill it. Even when driving for a bit with the low fuel light on, I have never been able to put more than 25 gallons in it. With a 31 gallon tank, I'd expect to get more in. The gauge has read a max of 3/4 full.

I had the in-tank fuel pump replaced recently, a job that required dropping the tank. Since then, I can't get it past half tank indicated easily. This could be a further miscalibration of the float, or the filler neck could have been misadjusted.

However, on a long road trip recently, I tried trickling gas in on low flow to see if the vent was just plugged. I got it to take another couple of gallons before it overflowed and spilled a pint out on to the ground. The gauge read about 5/8 or 3/4 full.

When I stopped for gas again, I only put in 10 gallons before the nozzle stopped. I did the math on miles traveled, and I would have needed to get 25 mpg to use 10 miles in that time. So it's super unlikely. I just went ahead and avoided spilled gas and just refilled every 150-180 miles for the rest of the trip.

So questions: Filler/vent or gauge? Is this a DIY resolution? I'm reasonably handy, but I don't have a good place to do the work if it is going to take more than an afternoon.

Also, according to Tahoe Forum Thread, sounds like the cannister pellets may have clogged the vent. That thread also recommends seeing if a scan gauge agrees with the gas gauge. Any recommendations on a scan gauge?

 

[OR VietVet]

Very common problem that starts with over filling the fuel tank. When the nozzle clicks off, that is it. That is when the system is working properly on your rig. If the rig has problems filling, like yours does then I see why you attempt to fill more and more. On a recent trip I had problems at a Chevron with the filler clicking off but I know my evap system is all completely new. As I expected, it was the station pump itself because I have not had any problems since. Anyway, I see members here replacing this one piece and that one piece and continue to have problems. I say, bite the bullet and replace the entire system, like I did. But, I am a "thousandaire" so I do things like that.

 

[bajajoaquin]

Until Sunday, I was not an over-filler. I agree. When it clicks off, I stop. So whatever issue is there originated either with the previous owner or since the gas tank was dropped and reinstalled a week or two ago. But I'm still not sure if it's "just" the filler or if there's also an issue with the gauge, since I had an issue previously which seems to have gotten worse.

When you say replace the entire system, what system and parts are you referring to, exactly?

 

[nonickatall]

There is an evap system which has a vent valve and an charcoal canister which is designed to prevent toxic fumes from being released into the environment.

The vent valve is automatically open, when the vehicle is switched off, so that the air can escape when refueling. This then escapes via the activated carbon filter and the valve.

When the vehicle is started, the valve is closed so that the gases produced in the tank are drawn off via the engine and burned there.

If this ventilation no longer opens or the activated carbon canister is sealed, the air cannot escape when refueling and then what you have as a problem happens.

Here is a good explanation of the system.

 

[OR VietVet]

Until Sunday, I was not an over-filler. I agree. When it clicks off, I stop. So whatever issue is there originated either with the previous owner or since the gas tank was dropped and reinstalled a week or two ago. But I'm still not sure if it's "just" the filler or if there's also an issue with the gauge, since I had an issue previously which seems to have gotten worse.

When you say replace the entire system, what system and parts are you referring to, exactly?

I see that @nonickatall supplied a video about the evap system. I was not insinuating or meant to say that you caused the problem. Likely all started with the previous owner. The fuel gauge not reading correctly would be a separate issue but maybe, just maybe, that are related.

 

[bajajoaquin]

Thanks. Sorry if I sounded defensive.

I don't have a check engine light, but you're suggesting I replace both valves and the charcoal cannister?

 

[nonickatall]

The video was not because of the engine light but because the principle of the evap system is explained well here.

The evap system mainly checks if it is tight. If your vent valve hang closed, that might not result in an error code, but you can't refuel.

I wouldn't just replace things now. First analyze, then repair.

The vent valve is attached to the tank in front of the rear axle and can be relatively easily be removed. You can then check whether it is free and open, maybe add 12 volts to check if it switch.

Otherwise I would take a look at the canister, but it hangs a bit stupidly on the tank at the front a little above the tank and is not easy to remove without a lift.

But I would look for those places first...

 

[OR VietVet]

IMO, replace all, valves, sensors, solenoids, cannister and lines. Perfect time to drop tank and see what is going on with sender. Please tell me it is a GM pump and not aftermarket.

 

[bajajoaquin]

Thanks to you both.

It's probably aftermarket. I didn't replace it myself. I had a check engine light on for lean condition both banks (read that on my scangauge II). No vacuum leaks, but mechanic was saying that it ran lean under load, so was likely the fuel pump/filter assembly needing replacement. While I have had the filling issues, the fuel pump seems to have resolved my lean condition. Anyway he's usually pretty good about not buying the cheapest stuff available, so it's probably not the bargain, but also probably not a GM replacement part.

 

[nonickatall]

Did your problems with the fueling start after the replacement of the fuel pump?