Check your gas caps

Reply Subscribe

Thread Tools

Search this Thread

Feb 5, 2008 | 08:41 PM

casscodiesel

Thread Starter

Junior User

Joined: Dec 2007

Posts: 50

Likes: 0

Check your gas caps

i spent all day working on my truck. after putting it all back together it did the same bucking hesitanting thing after a short ride. after pulling over my truck was running really rough. I hopped out and pulled the gas cap off right before it stalled and the truck smoothed out. I left the gas cap off and the truck ran as good as ever even a little better.

thanks. cass

Feb 5, 2008 | 09:06 PM

fellro86

Hotshot

Joined: Feb 2004

Posts: 11,697

Likes: 3

From: Marengo, Iowa

Check your vent, it likely is plugged up...

Feb 5, 2008 | 09:12 PM

catfish101

Posting Guru

Joined: Mar 2005

Posts: 1,701

Likes: 0

From: KY

I had that happen on my 83 one time.

By the way it is a fuel cap on a diesel.

GAS is a bad word on this forum.

Feb 5, 2008 | 10:21 PM

PLC7.3

Post Fiend

Joined: Nov 2004

Posts: 5,638

Likes: 1

From: Manitoba

There is no vent on our tanks...... the cap does the venting. If yours is not allowing air back in then it should be replaced........

Fuel cap Vacuum and Pressure

Vacuum ..... 0.05 psi
Pressure......1.6 psi

Feb 5, 2008 | 10:45 PM

ford trans tech

Elder User

Joined: Aug 2007

Posts: 728

Likes: 0

yes the diesels use vented caps , vented caps are not allowed on gasoline units , and the injector pump also has enough low pressure draw (vacuum) capability that i have seen fuel tanks crushed by having non vented caps

Feb 6, 2008 | 02:02 AM

Dave Sponaugle

Post Fiend

Joined: Nov 2003

Posts: 21,285

Likes: 15

From: Nutter Fort, WV

Caps on my 86 are non vented.

There is a vent in the tank top with a roll over check valve so there is no fuel leaking out if the truck is upside down.

There is a small rubber tube from the vent that clips on the frame above each tank.

Feb 6, 2008 | 06:40 AM

fellro86

Hotshot

Joined: Feb 2004

Posts: 11,697

Likes: 3

From: Marengo, Iowa

Yep, I pinched the rear vent hose on my 86, and it would not fill until I cleared it. Little plastic valve on the top of the tank with the rubber hose hooked up to it, separate from the sender.