Chevrolet Repair: cant put fuel in tank, chevy astro van, chevy astro


Question
QUESTION: Hi Tom,
i have a 97 Chevy Astro Van 4.3l v6 AWD.  The problem im having is that i cant put fuel in the tank. the tank is almost empty, and when i go to put fuel in its just filling up the fill tube to the tank making the nozzle at the gas station shut off. i have tried 5 different stations all with the same result.  It took 10 min to get to .231 gals.  Im not getting any check engine light error codes either.  my guess is to much pressure in tank??  but i have no idea how to check this or where to start!  Thanks for your time
Brian.

ANSWER: HI BRIAN, JUST A THOUGHT HAVE YOU CHECKED THE TANK FILL NECK TO MAKE SURE IT HAS NOT COLLAPSED ?
SOMETIMES THE NECK IS PART RUBBER HOSE. CK THIS AND SEE. THE NEXT CAUSE COULD BE FROM THE ROLLOVER VALVE IN THE TANK NECK THAT HAS STUCK NOT ALLOWING ANY FUEL IN. THIS WOULD BE RARE HOWEVER, BUT I HAVE SEEN THIS HAPPEN.. THE MOST COMMON PROBLEM IS A EVAP VENT VALVE STUCK, KEEPING THE TANK PRESSURIZED TO MUCH TO ALLOW ANY FUEL TO GET IT..THIS IS PART OF YOUR EVAPORATOR EMISSION CANISTOR VENT VALVE,PURGE VALVE.. YOU COULD TRY TO REMOVE THESE VENT LINES COMING OUT OF THE TANK WHICH WILL BE NYLON AND THEY WILL GO TO THE CANISTER AND JUST LET THEM HANG OPEN AND TRY TO FILL IT LIKE THIS JUST AS A TEST..HAVE YOU EVER HAD THE CK ENG LIGHT COME ON ??? IF SO HAVE IT SCANNED AND YOU MAY FIND A CODE IN THE SYSTEM FOR A BAD VENT VALVE...GOOD LUCK TO YOU AND LET ME KNOW HOW YOU MAKE OUT,,,TOM..

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QUESTION: Thank you Tom for the quick reply!  I did crawl under there and check the fill neck, its not collapsed as far as i can tell, there are no visible kinks in it.  No check engine lights recently that i can remember. I'll disconect the vent lines in the morning and check, i'll keep you posted on what happens :)  Thanks again.

Brian.

ANSWER: OK BRAIN LET ME KNOW, I THINK YOU WILL FIND THE THE VALVE IS PROBABLY STUCK IF THE NECK LOOKS GOOD. LET ME NOW IN THE MORN. GOOD LUCK TOM..

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QUESTION: Good morning Tom,
Ok went out this morning and disconected the vent line coming from the tank to the evap canister and the purge line from the canister to the valve.  Took it to the gas station and had the same problem, would start to fill slowly and it would just fill up the fill neck, which causes the nozzle to trip off and the gas slowly drains from the fill nozzle to the tank.  So where exactly is that rollover valve?  is it in the fill neck?  Is there another flapper door in the fill neck some where that could be stuck??

Thanks again for your time

Answer
GM BRIAN, IAM VERY SURPRISED THAT THE EVAP VENT LINES DID NOT SOLVE YOUR PROBLEM.. THE ROLLOVER VALVE IS IN THE BASE OF THE FILL NECK...BUT AS I SAID THIS WOULD BE RARE..YOU SAY THE FILLER NECK AND HOSE LOOKS TO BE IN GOOD SHAPE. I WONDER IF IT LOOKS OK BUT MAYBE SOMETING IS GOING ON INSIDE OF THIS NECK ???? YOU SURE YOU REMOVED ALL OF THE VENT LINES TO THE TNAK AND NECK ??? I CHECKED ON OUR TSB'S ON THIS AND I AM ONLY COMING UP WITH EVAP VENT LINE PROBLEMS. GO FIGURE...CK THE NECK, THERE IS MORE THEN LIKELY A RESTRCTION [I HOPE] AND PLEASE GET BACK TO ME ON THIS I WOULD LIKE TO HELP YOU FIX THIS OR IF YOU FIND OUT WHAT IT IS PLEASE LET ME KNOW..GOOD LUCK TOM..
PS WED EVENING,I LOOKED THIS PROBLEM UP ON OUR [OLD TSB LOGS] AND THERE WAS A PROBLEM WITH THE FILLER RUBBER TUBE . THE INSIDE WAS DETERIORATING AND CLOSING UP..98 & 99 MODELS. WE ARE OFF ONE YEAR BUT IT IS WORTH A SHOT..PLEASE LET ME KNOW I LIKE TO KEEP THIS IN MY MEMORY BANK. WHATS LEFT OF IT !!!!   TOM