Tank Says Half Full But Won't Take Gas
02-21-2016, 08:31 PM
#1
Tank Says Half Full But Won't Take Gas I don't drive the car very much these days but I started it up for the first time in a few months to get it out on the road and fluids circulating. Gas was at about half tank so I figured I'd fill it up before putting it away again for a while. Put the pump in, but it won't pump more than a second or so. It keeps clicking and shutting off like (what I assume) when it doesn't have a good vacuum seal. So, try it about 5 more times, thinking it's just a faulty pump and then see gas pouring down the side of the car. So, I pull the pump out and gas is just sitting in a pool at the top of the gas inlet valve... 
It appears as if, though there's only half a tank of gas (according to my gas gauge and assuming it is correct), something is blocking gas from getting in the tank. Though, the other (remote) possibility is that perhaps the gauge is wrong but I reset the trip meter every time I fill up and it's currently around 110 miles which would corroborate the current tank level reading. So, that's a much less likely probability.
Thus, at this point, I'd be interested in knowing whether or not anyone can think of a reason the gas tube may become blocked or prevented from accepting gas. And, if so, how to inspect/address it. Also, as the other remote possibility, what is the easiest way to test if the gauge is somehow off?
Thanks, all.
It appears as if, though there's only half a tank of gas (according to my gas gauge and assuming it is correct), something is blocking gas from getting in the tank. Though, the other (remote) possibility is that perhaps the gauge is wrong but I reset the trip meter every time I fill up and it's currently around 110 miles which would corroborate the current tank level reading. So, that's a much less likely probability.
Thus, at this point, I'd be interested in knowing whether or not anyone can think of a reason the gas tube may become blocked or prevented from accepting gas. And, if so, how to inspect/address it. Also, as the other remote possibility, what is the easiest way to test if the gauge is somehow off?
Thanks, all.
02-22-2016, 12:13 PM
#2
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I dont know for sure about fbodies but on trucks they have a roll over valve flapper at the tank inlet which can hang. I took the pipe off and reached in and felt mine with my finger when I was having a similar issue in my yukon.
02-23-2016, 11:51 PM
#6
I don't drive the car very much these days but I started it up for the first time in a few months to get it out on the road and fluids circulating. Gas was at about half tank so I figured I'd fill it up before putting it away again for a while. Put the pump in, but it won't pump more than a second or so. It keeps clicking and shutting off like (what I assume) when it doesn't have a good vacuum seal. So, try it about 5 more times, thinking it's just a faulty pump and then see gas pouring down the side of the car. So, I pull the pump out and gas is just sitting in a pool at the top of the gas inlet valve...
It appears as if, though there's only half a tank of gas (according to my gas gauge and assuming it is correct), something is blocking gas from getting in the tank. Though, the other (remote) possibility is that perhaps the gauge is wrong but I reset the trip meter every time I fill up and it's currently around 110 miles which would corroborate the current tank level reading. So, that's a much less likely probability.
Thus, at this point, I'd be interested in knowing whether or not anyone can think of a reason the gas tube may become blocked or prevented from accepting gas. And, if so, how to inspect/address it. Also, as the other remote possibility, what is the easiest way to test if the gauge is somehow off?
Thanks, all.
It appears as if, though there's only half a tank of gas (according to my gas gauge and assuming it is correct), something is blocking gas from getting in the tank. Though, the other (remote) possibility is that perhaps the gauge is wrong but I reset the trip meter every time I fill up and it's currently around 110 miles which would corroborate the current tank level reading. So, that's a much less likely probability.
Thus, at this point, I'd be interested in knowing whether or not anyone can think of a reason the gas tube may become blocked or prevented from accepting gas. And, if so, how to inspect/address it. Also, as the other remote possibility, what is the easiest way to test if the gauge is somehow off?
Thanks, all.
UNFORTUNATELY on anything above 98 I believe, you have to remove the entire fuel tank to reach it, the trap door method may work but Im not 100% sure.
I went ahead and replaced everything since the tank had to come out. Fuel pump assembly aswell.
02-23-2016, 11:53 PM
#7
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Could be this. I had the same problem. There's a valve under a green cap on the fuel line on the driver side of the motor. Use a screwdriver/pen/key to press down the valve and it should let the air out of the system. Then you should be able to fill up. Hope this works!
Could be this. I had the same problem. There's a valve under a green cap on the fuel line on the driver side of the motor. Use a screwdriver/pen/key to press down the valve and it should let the air out of the system. Then you should be able to fill up. Hope this works!
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02-23-2016, 11:59 PM
#8
https://ls1tech.com/forums/general-m...into-tank.html
Could be this. I had the same problem. There's a valve under a green cap on the fuel line on the driver side of the motor. Use a screwdriver/pen/key to press down the valve and it should let the air out of the system. Then you should be able to fill up. Hope this works!
Could be this. I had the same problem. There's a valve under a green cap on the fuel line on the driver side of the motor. Use a screwdriver/pen/key to press down the valve and it should let the air out of the system. Then you should be able to fill up. Hope this works!
05-25-2016, 05:15 PM
#10
Little update... purging the valve under the green EVAP cap didn't do anything. So, looks like the tank has to be dropped to replace the canister. Oy. Any way to easily ensure that's it before the tank is dropped?
Assuming that's it, any insight into the hours/effort that is going to take?
Assuming that's it, any insight into the hours/effort that is going to take?
06-06-2016, 02:02 AM
#11
3
Probably a silly question, but you've tried this at multiple gas stations correct?
I had almost the exact same issue and it turned out to be some weird thing with the station I was going to. Went to once across the street and didn't have a problem.
Probably a silly question, but you've tried this at multiple gas stations correct?
I had almost the exact same issue and it turned out to be some weird thing with the station I was going to. Went to once across the street and didn't have a problem.
06-06-2016, 03:17 PM
#12
I haven't tried it at another gas station. It's the same station I use to fill up all our other cars. So, unless it is something specific to this tank on my LS1, we haven't had any issues otherwise at the station (brand new Chevron built only a year ago).
06-06-2016, 03:32 PM
#13
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When this is related to tank pressure (improper vent from EVAP system), some have successfully pushed that flapper in the fill neck (mentioned earlier) back down with a straighten coat hanger. Of course, if you've already started to fill with fuel then you might get a nice spray of that fuel right in the face when you allow tank pressure to escape by pushing the flapper back down - so be careful and stand to the side. I've read that those with this issue often don't encounter it again unless they let the tank drop below about the ~1/3 range or so. I've never dealt with this myself, so I can only mention what I've heard/read in the past.
On the other hand, there is this:
I've encountered this issue at a few gas pumps before, where they just won't fill properly on certain cars I own, even though others are fine. There was one pump in particular that I always used at a local station, and then one day it just wouldn't work for my '02 Z28 at all. The car filled fine on other pumps, and other cars I owned filled fine on THAT pump, but something about that one pump and one car was an issue. 
So maybe try another pump/station as a simple test.
On the other hand, there is this:
So maybe try another pump/station as a simple test.
06-06-2016, 04:16 PM
#14
Little update... purging the valve under the green EVAP cap didn't do anything. So, looks like the tank has to be dropped to replace the canister. Oy. Any way to easily ensure that's it before the tank is dropped?
Assuming that's it, any insight into the hours/effort that is going to take?
Assuming that's it, any insight into the hours/effort that is going to take?
I dont know how willing you are to do your own work but from my knowledge you will need to drop the rear axel to do this as Im not sure you will be able to reach the canister via the trap door method. If you drop the fuel tank, you need to replace the fuel pump while you're there. Overall it costed me about $1k to fix this, $500 in labor, $500 in parts because I decided to replace the fuel pump while I had the opportunity to, no point in taking all of that apart and the pump dies 300 miles down the road and you gatta do it again.
06-07-2016, 10:50 AM
#15
Thanks for the info, Need. Very much appreciated.
I already have a Walbro in there, replaced the OEM a while back when I put in the 408. Either way, I have the trap door cut in the trunk if I ever do have to replace the pump again in the future, but good advice.
If only the Evap canister could be replaced as easily...
I already have a Walbro in there, replaced the OEM a while back when I put in the 408. Either way, I have the trap door cut in the trunk if I ever do have to replace the pump again in the future, but good advice.
If only the Evap canister could be replaced as easily...