Register or Log In To remove these advertisements. |
|
|
|
Thread Tools | Display Modes |
|
03-07-2021, 12:20 PM | #1 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,714
|
Blazer gas tank plugged vent tube at the tank.
We completely rebuilt a '72 Jimmy for my son. Original tank. It was flushed out and looks good inside. Now that the truck is on the road we have found the vent tube going into the tank is plugged. I can put 100psi of air pressure on it and it just blows back out the vent opening. If you hold the rubber nozzle on it tight enough after you stop adding air and let off, it vents pressure back out. So NOTHING goes into the tank.
Anybody had one of these tanks cut apart? Is there some sort of one way valve inside the tank? Trying to push a coat hanger through it forcibly contacts something, and that does not happen in the smaller charcoal cannister fittings. I have an air vacuum pump I may try to hook and and see if it might pop a valve loose.
__________________
44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax |
03-07-2021, 12:28 PM | #2 |
Who Changed This?
Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,244
|
Re: Blazer gas tank plugged vent tube at the tank.
There is only a valve at the vapor canister that opens when vacuum hits it- when the truck is running. There should be nothing blocking the flow of fuel vapors to the canister. It probably has some crud in the line. The line runs up the back of the cab on the passenger's side before going to the canister.
__________________
~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
03-07-2021, 04:11 PM | #3 |
Senior Member
Join Date: Nov 2018
Location: Waterford California
Posts: 2,436
|
Re: Blazer gas tank plugged vent tube at the tank.
Put a vented cap on it and forget about it.
|
03-07-2021, 04:59 PM | #4 |
Senior Member
Join Date: Aug 2019
Location: Cheraw
Posts: 1,305
|
Re: Blazer gas tank plugged vent tube at the tank.
Could be you are a victim of a mud dauber wasp.
|
03-07-2021, 07:29 PM | #5 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,714
|
Re: Blazer gas tank plugged vent tube at the tank.
I completely flushed the tank when we took the truck apart. The two 5/16 lines for the charcoal cannister are clear. The 1/2" vent to the filler is not... I could not push a coat hanger through it. I put a vacuum on it and nothing. I sealed up everything else on the tank and put 90 psi of air on one of the 5/16 lines. It caused the tank to expand and then pushed fuel out the filler neck. I soaked it in Seafoam before this.
It is completely and perfectly 100 % blocked. In the mean time I have routed the filler neck vent to one of the 5/16 nipples. My brand new fuel sender failed after the first full tank of fuel so the tank has to come out again. I will investigate more at that point. If I cannot get that one to vent I will tee the two 5/16 into the 1/2 vent line.
__________________
44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax |
03-07-2021, 07:31 PM | #6 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,714
|
Re: Blazer gas tank plugged vent tube at the tank.
You can't fill it up with the filler neck vent blocked. After about a gallon of gas, it burps the next 1/2 gallon down the side of the truck.
__________________
44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax |
03-09-2021, 12:44 AM | #7 | |
Senior Member
Join Date: Nov 2018
Location: Waterford California
Posts: 2,436
|
Re: Blazer gas tank plugged vent tube at the tank.
Quote:
My avatar has no tank vent except the vented cap and I can fill it as fast as the pump will pump. |
|
03-07-2021, 11:54 PM | #8 |
Carpe manana
Join Date: Dec 2010
Location: Eau Claire, WI
Posts: 12,336
|
Re: Blazer gas tank plugged vent tube at the tank.
Does the fuel filler neck match this one piece style? The vent at that end of the tank should just be an open tube no valve.
__________________
1972 K5 CST Highlander Blazer: http://67-72chevytrucks.com/vboard/s...d.php?t=708547 1972 K20 Cheyenne Super: http://67-72chevytrucks.com/vboard/s...d.php?t=528308 Members met: ORANGBLAZ, 2003 silverado, MikeCofield, BB72CHEVKT, Duncan&Son, Sameyrasmea72, THENEWMEXICAN, HotRod C/10, brianthelion02, Sport/Truck, ryanroo, michael bustamante, Dirt's72, Already Gone, WestButteTruck, 57taskforce, Moreyel, painterljp, AASmedic, SoCoC10, Lumaestas, carbuff382, Chevyland |
03-08-2021, 10:04 PM | #9 |
Registered User
Join Date: Dec 1999
Location: Austin, TX, USA
Posts: 7,714
|
Re: Blazer gas tank plugged vent tube at the tank.
It looks just like that. But there is something in the tank vent. It is COMPLETELY blocked inside the tank. Cannot force a coat hanger in it and pressurizing it with my air compressor doesn't put any air into the tank.
__________________
44 Willys MB 52 M38A1 64 Corvette Coupe 68 Camaro 'vert LT1 & TH700 69 Z/28 355 12.6's @110 69 Chevy Short Step 4 1/2"/7" drop 72 Jimmy 4WD 4spd 4" & 35's 02 GMC 2500HD 4x4 Duramax |
03-08-2021, 10:45 PM | #10 |
Who Changed This?
Join Date: Jan 2013
Location: Simi Valley, CA
Posts: 10,244
|
Re: Blazer gas tank plugged vent tube at the tank.
SheepDip has your solution.
__________________
~Steven '70 Chevy 3/4T Longhorn CST 402/400/3.56 Custom Camper Simi Valley, CA |
Bookmarks |
|
|