EVAP system wont let me fill tank

Tiny
JFADKINS
  • MEMBER
  • 2005 CHEVROLET EXPRESS
  • 6.0L
  • V8
  • 2WD
  • AUTOMATIC
  • 60,000 MILES
I have a motorhome with a chevy express chassis. Tried to fill tank and the gas came right back out. Took it to a repair shop and had purge and vent valves replaced. Repairs made no difference and still can't fill the tank. Any suggestions?
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Wednesday, November 18th, 2015 AT 5:42 PM

9 Replies

Tiny
HMAC300
  • EXPERT
Check to see if vent line is blocked or kinked. It may not be able to take gas fast and will have to be filled slow.
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Thursday, November 19th, 2015 AT 6:17 AM
Tiny
JFADKINS
  • MEMBER
Thanks for responding. I checked the vent line and no kinks. I blew air through it and it was clear. I ran a 1/8" fiberglas rod down both lines to be sure and may have hit something in the fill line (maybe a valve?) About 3 feet down. It's almost impossible to get any gas into the tank now.
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Thursday, November 19th, 2015 AT 9:11 AM
Tiny
HMAC300
  • EXPERT
If this is the factory tank you are talking about there is an anti rollover valve there, that may be stuck I have no idea how to fix that as it is part of the tank unless you took off the fill tube and found something in that or something blocking the tank you might be able to free it up but not sure how it works as I've never run into that problem. The only other thing I can think of is the evap is plugged from to much fuel so you might try draining it and see why it's not working. The fuel tank should never be filled after an initial stop when pump stops is what I mean.
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Thursday, November 19th, 2015 AT 9:34 AM
Tiny
JFADKINS
  • MEMBER
The repair shop is going to use a smoke machine to check the other valves. I think it may be the rollover valve you mentioned. Is the rollover valve in the fill line near the tank? Again thanks for your help! I've $200 in parts and labor for the new valves. Who knows how much I'll have before this is fixed.
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Friday, November 20th, 2015 AT 10:35 AM
Tiny
HMAC300
  • EXPERT
No the valve Is in the tank, but if they check the evap it will tell of leaks not if it is overfull or not as it might be pic shows things to check
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Friday, November 20th, 2015 AT 12:00 PM
Tiny
JFADKINS
  • MEMBER
Thanks for your help. Still have the problem of not being able to fill the tank. Took the Motorhome to 3 different shops and no one can figure it out. So far, changed the purge and vent valves, evap canister, replaced and rerouted fill line vent hose, removed and inspected fill line gas hose, Checked the inlet to the tank; it doesn't have any obstructions. This is so strange cause I've had this MH for 2 years and it never had this trouble. Something mechanical has failed, but what?
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Saturday, December 5th, 2015 AT 5:34 PM
Tiny
HMAC300
  • EXPERT
The rollover valve should be where gas goes inside tank. If there is a clear path to tank from filler neck and vent line is not kinked or partially blocked I have no idea what to tell you. I've worked on motor homes and if it's a tank the motor home place put it they are usually steel with no blockage I have found other problems with those tanks however but nothing like what you are experiencing. The only thing I can suggest is to blow air through lines to see if there is a blockage as I cannot see this. I have nothing more to suggest as it's hard for me to help with this.
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Sunday, December 6th, 2015 AT 7:54 AM
Tiny
JFADKINS
  • MEMBER
Thank you for trying. The last thing Im going to try is the fuel fill line has a fitting in it that goes to the gas generator. Maybe there is a leak in that hose that may cause it to draw air in and vapor lock the fill line. I'm going to take the line out and get a fill hose that runs from the metal fill line directly to the tank. I'm out of ideas.
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Sunday, December 6th, 2015 AT 11:16 AM
Tiny
HMAC300
  • EXPERT
Try blowing them out with air first if it blows air it should be ok.
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Sunday, December 6th, 2015 AT 12:22 PM

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