87 TBI fuel pouring out of charcoal canister??? WTH - The 1947 - Present Chevrolet & GMC Truck Message Board Network

spudz · 08-12-2011, 09:16 AM

OK so I just got this truck. Its a 87 4.3 TBI. The guy I got it from said it would run good for a while and then start running bad and running rich. SO I started messing with it for a little while yesterday and it started pouring fuel out of the charcoal canister? Not just a little bit either. How in the hell can it be pushing raw fuel out of the vent like that??? I pulled the gas cap off and it released alot of pressure so I am guessing its building pressure some how. Anyways, I'm pretty good at this and I have no idea why its doing that.... Any ideas? Only thing I can think to do is, drop the tank this weekend and make sure any lines arnt crossed or pinched

spudz · 08-12-2011, 09:47 AM

After looking at a pic of a sending unit.... the only thing I think it could be is the vent and return lines are crossed at the sending unit. I need to drop the tank to fix the gas gauge anyways.

BLE 'BURBAN · 08-12-2011, 10:44 AM

Should be 3 different sizes of fuel lies back there on the tank.
1. 3/8" fuel line feed
2. 5/16" fuel return
3. 1/4 fuel vapor line.

blazinzuk · 08-13-2011, 04:51 AM

Quote:

Originally Posted by spudz

After looking at a pic of a sending unit.... the only thing I think it could be is the vent and return lines are crossed at the sending unit. I need to drop the tank to fix the gas gauge anyways.

FTW, I moved my gas tank in my truggy and this happened to me and all I did was have the lines a little mixed up. Quick and easy fix for me because my gas tank is exposed

08-12-2011, 09:16 AM	#1
spudz Registered User Join Date: Oct 2005 Location: Branchville SC Posts: 1,647	87 TBI fuel pouring out of charcoal canister??? WTH OK so I just got this truck. Its a 87 4.3 TBI. The guy I got it from said it would run good for a while and then start running bad and running rich. SO I started messing with it for a little while yesterday and it started pouring fuel out of the charcoal canister? Not just a little bit either. How in the hell can it be pushing raw fuel out of the vent like that??? I pulled the gas cap off and it released alot of pressure so I am guessing its building pressure some how. Anyways, I'm pretty good at this and I have no idea why its doing that.... Any ideas? Only thing I can think to do is, drop the tank this weekend and make sure any lines arnt crossed or pinched __________________ 2004 z71, 96 z71 on 38s, 88 Chevy k5 blazer, 4in lift. 84 swb project, 82 SWB project , 84 chevy 4x4 lwb project, 88 Jimmy beater/highschool ride. 79 c30. 99 tahoe 4x4 project. and a bunch of parts trucks..

08-12-2011, 09:47 AM	#2
spudz Registered User Join Date: Oct 2005 Location: Branchville SC Posts: 1,647	Re: 87 TBI fuel pouring out of charcoal canister??? WTH After looking at a pic of a sending unit.... the only thing I think it could be is the vent and return lines are crossed at the sending unit. I need to drop the tank to fix the gas gauge anyways. __________________ 2004 z71, 96 z71 on 38s, 88 Chevy k5 blazer, 4in lift. 84 swb project, 82 SWB project , 84 chevy 4x4 lwb project, 88 Jimmy beater/highschool ride. 79 c30. 99 tahoe 4x4 project. and a bunch of parts trucks..

08-12-2011, 10:44 AM	#3
BLE 'BURBAN In the Forgotten far North. Join Date: Jul 2007 Location: Anchorage, Alaska Posts: 2,627	Re: 87 TBI fuel pouring out of charcoal canister??? WTH Should be 3 different sizes of fuel lies back there on the tank. 1. 3/8" fuel line feed 2. 5/16" fuel return 3. 1/4 fuel vapor line. __________________ 1987 R3500 CREW CAB DUALLY (BIG RED)Acquired 06/12/2015 1990 chevy suburban V2500 5.7L My cluster Mods-Nov 2007 overhead console Stereo install Round 2 Aug 2009 Heated/turn signal mirror upgrade



Register or Log In To remove these advertisements.

Register or Log In To remove these advertisements.