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Filling up with gasoline problem

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10K views 57 replies 11 participants last post by  bg888  
#1 · (Edited)
OK, yes...I'm a newbie. Sorry for posting so many questions here...

I just filled it up for the second time. And for the second time, when it hit shut off, a bunch of gasoline back washed out and ran down the fender and left a small puddle on the ground. Embarrassing. What am I doing wrong?

Sort of related, I read in the manual about this "capless funnel adapter" to use if using a gas can that's supposed to be found inside the car. Where is it?

Thanks again.
 
#2 ·
No worries about asking questions- that's one of the things we are all here for. There are large variances in the auto-stop on gas station pump handles. There are some that will shut off almost immediately after you start pumping and one way to get that type to work is slide the nozzle very slightly out of the C7 neck and try again. Some you won't have any issues with and some will prematurely shut off. Know approximately how many gallons you need and if it shuts off well before that amount click it back on. If you try to top a fill most of the time you will get some gas coming back out.

The plastic funnel adapter should be back in your trunk, right (passenger) side, just under the carpeting in a hard foam cover near the battery.
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If it is not there, it could be in the small cubby on the left rear side of your trunk. You only would need that if you are trying to fill using a gas can or similar. Our C7s have a flap in the neck that normally gets opened by the regular gas station nozzle, but if you just attempt to pour gas into the filler tube without the flap being opened, it will not go down.
 
owns 2018 Corvette C7 2LT
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#4 ·
I have never had that happen to me. Make sure you have the nozzle all the way in. Wiggle it around gently while pushing it in to be sure you have it fully inserted.
 
#5 ·
Also, if it keeps happening after you are sure the nozzle is all the way in, use a different nozzle (different pump at the same service station, or a different service station).
 
#6 ·
The capless gas filler has two rubber flappers in the tube. The one you see at top and a second one a few inches down. If you pull the fuel filler nozzle out of the lower one while still pumping gas the fuel will come back at you as the lower flapper closes off very strongly. Always keep the nozzle in all the way and then shut off and wait a few seconds for it to stop dripping and then remove the nozzle.

hope this helps
 
#7 ·
The problem is when the nozzle shuts off. I have the nozzle all the way in as it can’t go any further. When it automatically shuts off is when the back wash happens. In thinking further about this and replaying it back in my mind, when it shuts off and I pull the nozzle out, I see it pouring out gas from the nozzle even though it’s shut off, like it overfilled the tank and surplus gas in the nozzle is running out.
 
#8 ·
The vent to the gas vapor canister is just a few inches below the lower flapper. If indeed the tank is overfilling the car should show a signal on dash, because over filling to the point of getting fuel in the gas canister will cause problems with the emissions system. Try stopping the fill before it clicks off and remove the nozzle. then reinsert and fill the rest of the way. This is just to get the feel of the flapper. wait 10 seconds before removing the nozzle. Pull it back and you can feel the lower flapper pressure on the nozzle tip, make sure the tip of the nozzle is still holding the flapper open until fuel is drained from the nozzle.

Hope this helps
 
#9 ·
One other thing I noticed is that I could smell gasoline fumes standing at the back of the car. That has dissipated, but now that I'm swapping out the battery, I smell it in the trunk. I'm assuming that the smell will eventually go away. I'm hoping that this is nothing to worry about.
 
#10 ·
You should not smell any fumes in the trunk. Possibly when you filled it and it overflowed, some of the residual is what you are smelling. If you continue to smell gas in your trunk you need to have the overflow tube and filler tube checked to make sure all is correct.

Remember when you replace the battery to make sure the vent tube is reconnected to the new battery as well as the small black wire is also reconnected to the negative post as shown in my battery replacement write-up.
 
owns 2018 Corvette C7 2LT
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#12 ·
If it were mine, I would recommend the dealer with a C7 trained technician.
 
owns 2018 Corvette C7 2LT
#14 ·
I can think of no reason you should have fuel smell in the trunk area of the car! First thing in the morning after the car has set overnight, is there any fuel smell in the car, or around the car.

There are actually two fuel tanks in the car. They are connected and have a vent line that runs high under the ridge behind the seats. Was there any modifications done to the car in this area?

If no fuel smell in the morning then check for smell after a short drive. Then check for fuel smell after a fill up without a spill.

If the smell comes back under any of these conditions it could be a leak in the vent line, supply line, return line or other.
If it does not come back then rest easy but if it does come back a fuel leak should not be ignored.
 
#16 ·
I can think of no reason you should have fuel smell in the trunk area of the car! First thing in the morning after the car has set overnight, is there any fuel smell in the car, or around the car.

There are actually two fuel tanks in the car. They are connected and have a vent line that runs high under the ridge behind the seats. Was there any modifications done to the car in this area?

If no fuel smell in the morning then check for smell after a short drive. Then check for fuel smell after a fill up without a spill.

If the smell comes back under any of these conditions it could be a leak in the vent line, supply line, return line or other.
If it does not come back then rest easy but if it does come back a fuel leak should not be ignored.
Thanks for this information. Yes, I smell it even after just a very short drive consisting of just backing it in the driveway. I guess to the dealer it goes.
 
#15 ·
You didn't say what year your car is, but I know that the 2016 cars were subject of a letter about possible cracks in the fuel pump attachment point on the tank. Here is a copy of hte letter I got. --Bob

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#17 ·
You didn't say what year your car is, but I know that the 2016 cars were subject of a letter about possible cracks in the fuel pump attachment point on the tank. Here is a copy of hte letter I got. --Bob
I have a 2014. I guess I need to create a signature in my profile. Thanks for thinking of this and putting in the effort to find and post this letter to help me out, I appreciate it!
 
#20 ·
That should work fine. Was the tube actually removed from your C7 or just pushed aside?
 
owns 2018 Corvette C7 2LT
#21 ·
The rubber tube is there and was pushed aside, but the hard plastic part is missing from it and the battery.

I also have to get a new washer thing that's on the end of the small ground wire you spoke of. It's broken off and that's why it wasn't connected. Need to get the part from ACE Hardware or something and splice it back together. Oy. This car and it's problems...I just keep telling myself it's worth it.
 
#22 ·
OK, so remove the right angle plastic connector and insert it in the tube still attached to and through your C7 floor, then attach it to the replacement battery (or your next replacement battery). They do sell eyelets that you can either solder or crimp onto the black wire and then attach to the negative terminal.

Sorry you have experienced these hiccups with your new purchase. Unfortunately when purchasing a used Corvette (especially if you do it from a non Chevy dealer or without any Certified warranty from the seller) and if you are not very familiar with the specific model, it is easy to overlook potential issues. It always helps to have someone who is knowledgeable of the car with you to give it a thorough look over. Hopefully you have discovered all of them by now and won't have further surprises.
 
owns 2018 Corvette C7 2LT
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#23 ·
Sorry you have experienced these hiccups with your new purchase. Unfortunately when purchasing a used Corvette (especially if you do it from a non Chevy dealer or without any Certified warranty from the seller) and if you are not very familiar with the specific model, it is easy to overlook potential issues. It always helps to have someone who is knowledgeable of the car with you to give it a thorough look over. Hopefully you have discovered all of them by now and won't have further surprises.
Having never owned a Vette before, this has definitely been a learning experience. Thank heavens for this site and you and the others! These cars are increasingly more sophisticated. Reading the manual is going to take a few days...

Thanks again!
 
#24 ·
Pleased we are able to help. Hopefully you can get together with other Corvette owners in Tucson- not sure what Corvette club(s) are there, I know there are several in Scottsdale.
 
owns 2018 Corvette C7 2LT
#29 ·
Welcome! Ask away! I do! One thought that I’ve had happen is a particular gas station has pumps that pump extra fast and hard and creates a backwash when it fills the tank so fast even though tank may not be full. I find when I get close to filling the tank, I slow it down by barely pressing the lever. Problem solved unless I’m admiring another vehicle in the station!!
 
#30 ·
Dear Red Vette,

Agree with all who suggest something is wrong with your car - so sorry!

We put over 100,000 miles on our 2014 non-Z51 coupe with the M7. Almost all miles were on road trips. Most of the time I “topped off” when filling. I know everybody says you shouldn’t! I always did so very carefully!

I always held the nozzle and kept the flow rate below or equal to the slowest/ lowest rate of the “first notch” on the nozzle handle. I never experienced fuel “spitting back”. The car usually took 0.8 to 0.9 gallons after the nozzle “clicked” off - I know because I logged all the gas put into the car (I still have the spreadsheet).

We never experienced fuel smell in the car. Of course we didn’t have a separate trunk like you have.

Best of luck and warm regards, bob
 
#49 ·
Well, bad news. The fumes returned every time I put fuel in the car. Took it to the dealer. Bad news is that both fuel pumps were shot which was causing the fumes and most likely the backwash when the gas pump nozzle shut off. I'm glad they found the problem. I'm not glad it's going to cost me $3400 to fix.