Bubbles in Gas Line
07-10-2010, 08:23 PM
#1
Thread Starter
Join Date: Jun 2010
Location: IN
Posts: 35
Bubbles in Gas Line
1963 Ford Falcon Futura, 6 cyclinder 170 2.8, FordOMatic Transmission
Placed a 6 inch segment of clear gas line right before the carb off the stock metal fuel line so I could see what was going on. It had bubbles (Lots and big) in it so I thought vapor lock. So I replaced the stock metal fuel line with one piece of clear fuel line running from the fuel pump to the carb. Made sure it was nowhere need a heat source. Once warm the fuel pump would spit out lots and lots of bubbles, 1/3 air 2/3 gas. This is the second fuel pump that I've had on it. What could be going on? Two bad fuel pumps? Got them from AutoZone.
Any help much appreciated.
Placed a 6 inch segment of clear gas line right before the carb off the stock metal fuel line so I could see what was going on. It had bubbles (Lots and big) in it so I thought vapor lock. So I replaced the stock metal fuel line with one piece of clear fuel line running from the fuel pump to the carb. Made sure it was nowhere need a heat source. Once warm the fuel pump would spit out lots and lots of bubbles, 1/3 air 2/3 gas. This is the second fuel pump that I've had on it. What could be going on? Two bad fuel pumps? Got them from AutoZone.
Any help much appreciated.
07-10-2010, 08:33 PM
#2
6th Gear Member
Join Date: Jan 2007
Location: AR
Posts: 5,469
I want to imagine that a slightly torn fuel pump diaphram might pick up some air from the crankcase...
How old is your fuel pump?
Kind of a cheezzy answer, but it was all I could come up with....
How old is your fuel pump?
Kind of a cheezzy answer, but it was all I could come up with....
Last edited by JMD; 07-10-2010 at 08:56 PM.
07-10-2010, 08:37 PM
#3
Thread Starter
Join Date: Jun 2010
Location: IN
Posts: 35
The fuel pump is brand new. Just put it on. The one prior was new also. Put it on a couple months ago. Changed it out because it made a clicking sound. The most recent one's box looked like it had age on it. Looked like it had been sitting on the shelf a while discolored/yellowed sticker.
07-10-2010, 09:06 PM
#5
Thread Starter
Join Date: Jun 2010
Location: IN
Posts: 35
07-11-2010, 10:18 AM
#7
3rd Gear Member
Join Date: Jul 2009
Location: Smyrna, TN
Posts: 678
Every time I've used a clear filter on the line running from the FP to the carb. it always has air in it, the fuel system is not always under pressure with a mech. pump so gravity will force air to the top. If you move the filter to the line that comes out of the fender apron to the FP (horizontal and low) you probably won't see any air bubbles.
Is the car running bad? or what is the issue? If it's just the air bubbles in the filter I've never seen one installed there that doesn't have air in it, it's not a sealed system like EFI.
Jon
Is the car running bad? or what is the issue? If it's just the air bubbles in the filter I've never seen one installed there that doesn't have air in it, it's not a sealed system like EFI.
Jon
07-12-2010, 06:57 AM
#8
Thread Starter
Join Date: Jun 2010
Location: IN
Posts: 35
After the car warms up it starts running rough. It dies both when going down the road for an unknown reason and it dies when it's put in reverse or drive. Both occur only when it's warm. Runs great when cold. I've been thru the entire ignition system, replaced carb, checked timing and compression.
The bubbles in the fuel line are not there when the car is cold. They become visible once the car heats up.
The bubbles in the fuel line are not there when the car is cold. They become visible once the car heats up.
07-12-2010, 07:09 AM
#9
Thread Starter
Join Date: Jun 2010
Location: IN
Posts: 35
Every time I've used a clear filter on the line running from the FP to the carb. it always has air in it, the fuel system is not always under pressure with a mech. pump so gravity will force air to the top. If you move the filter to the line that comes out of the fender apron to the FP (horizontal and low) you probably won't see any air bubbles.
Is the car running bad? or what is the issue? If it's just the air bubbles in the filter I've never seen one installed there that doesn't have air in it, it's not a sealed system like EFI.
Jon
Is the car running bad? or what is the issue? If it's just the air bubbles in the filter I've never seen one installed there that doesn't have air in it, it's not a sealed system like EFI.
Jon
07-13-2010, 07:14 PM
#10
3rd Gear Member
Join Date: Jul 2009
Location: Smyrna, TN
Posts: 678
HMMMM...just guesses but:
Vapor lock from the tank > gas cap sealing too well, maybe a different than original cap or if there is some sort of vent to the tank (don't believe so) could be clogged.
Filter sock on fuel sender in tank is clogged/collapsed, etc. causing restriction = stumbling when warm, trash in tank clogging metal lines.
Soft rubber fuel line section that is collapsing internally? Be sure to replace ALL rubber line pieces from the tank sender to FP.
A vacuum leak at the engine - any old lines to dist. or carb, there is probably 2 pieces of rubber vac. line to the trans, one at the rear of the engine and one at the back of the trans to the trans modulator, either of these would cause a vacuum leak that would worsen when warm.
Jon
Vapor lock from the tank > gas cap sealing too well, maybe a different than original cap or if there is some sort of vent to the tank (don't believe so) could be clogged.
Filter sock on fuel sender in tank is clogged/collapsed, etc. causing restriction = stumbling when warm, trash in tank clogging metal lines.
Soft rubber fuel line section that is collapsing internally? Be sure to replace ALL rubber line pieces from the tank sender to FP.
A vacuum leak at the engine - any old lines to dist. or carb, there is probably 2 pieces of rubber vac. line to the trans, one at the rear of the engine and one at the back of the trans to the trans modulator, either of these would cause a vacuum leak that would worsen when warm.
Jon
