Strange Vapor locking Maybe? thoughts please
Thread Starter
|
Senior User
Joined: Jul 2014
Posts: 123
Likes: 0
From: Seattle
Strange Vapor locking Maybe? thoughts please
Details
1982 f150 regular cab 4x4,
Sitting at a stop light and go to take off had it hesitates, stumbles then picks up and goes.
When its warm and off sometimes you have to hold the pedal to the floor to get it to start.
Fuel line comes up behind the AC, wraps around the carb to the dual fuel inlets on the summit 4010 carb. this is the same carb before the rebuild.
I noticed that the fuel filter cold is full, as the engine warms and I drive it the filter level starts dropping, when I stop and look quickly the fuel filter is almost empty.
when the engine cools the fuel filter refills. There is no fuel filter under the cab.
Thinking of replacing the lines from the Dual tank split forward and/or rerouting the fuel line across top the engine vs around the carb.
OR move the a fuel pump......
Anyone have any ideas or thoughts?
1982 f150 regular cab 4x4,
Sitting at a stop light and go to take off had it hesitates, stumbles then picks up and goes.
When its warm and off sometimes you have to hold the pedal to the floor to get it to start.
Fuel line comes up behind the AC, wraps around the carb to the dual fuel inlets on the summit 4010 carb. this is the same carb before the rebuild.
I noticed that the fuel filter cold is full, as the engine warms and I drive it the filter level starts dropping, when I stop and look quickly the fuel filter is almost empty.
when the engine cools the fuel filter refills. There is no fuel filter under the cab.
Thinking of replacing the lines from the Dual tank split forward and/or rerouting the fuel line across top the engine vs around the carb.
OR move the a fuel pump......
Anyone have any ideas or thoughts?
Moderator
Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
I have had several trucks do this, when moving down they road they were fine. Come to a stop light and they would start throwing a fit, eventually stalling and not running till they cooled off. They were also header equipped, custom trucks. What fixed both was to re-route the line on the outside of the frame. The books will tell you as long as you are 3 inches or so away from the exhaust you will be fine, but that doesn't work. If you have the stock pump, run from that through a hole in the frame or over the top or bottom of the driver's side frame rail, and then sneak it past the front suspension on the frame using plenty of clips. Run it down the frame, and then run it to the fuel tank. If you happen to cross the exhaust onto the outside of the frame, then you need to cross the fuel line back on the other side of the frame, using the frame as a heat shield.
Lead Driver
Joined: Nov 2013
Posts: 7,174
Likes: 1,174
My experience here, see post #6:
The importance of keeping your carb cool, and other bedtime stories
I suspect much of your problem is heat soak of the carb, from the exhaust crossover passage inside the intake manifold. Note I’m running stock cast iron exhaust manifolds. I don’t think your headers help keep underhood temperatures within reason, but what’s that saying about opinions?...
More travails here:
Electric fuel pump conversion
The importance of keeping your carb cool, and other bedtime stories
I suspect much of your problem is heat soak of the carb, from the exhaust crossover passage inside the intake manifold. Note I’m running stock cast iron exhaust manifolds. I don’t think your headers help keep underhood temperatures within reason, but what’s that saying about opinions?...
More travails here:
Electric fuel pump conversion
Junior User
Joined: Apr 2013
Posts: 65
Likes: 0
I installed one of these near the carb on my 83 F150 351W and ran the return line back to the the tank. I made a tee with a piece of exhaust pipe and a 1/4" barbed fitting for the return line and installed it in the tank filler hose. This solved my vapor lock problem. I live in South Georgia and it gets hot here in the summer and this truck can idle all day and have no more problems taking off from a red light. Just wanted to share, as this is an easy fix and it works.
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
The issue is the ethanol laced fuels has a lower boiling point than the pure gasoline of days gone by so we are seeing this issue crop up. A noted by Sandgnat that is the best way to combat it , add a return line. This keeps cooler fuel from the fuel tank always circulating and will help prevent vapour lock there are many ways to do this, the above is one and probably the easiest.
Lead Driver
Joined: Nov 2013
Posts: 7,174
Likes: 1,174
Junior User
Joined: Apr 2013
Posts: 65
Likes: 0
Yes, the vent on the filter has a very small hole and it will not effect the running of the engine. It allows the vapor and a small amount of fuel to return to the tank. It works great, I put one on my 79 Lariat Ranger as well.
Trending Topics
FTE Legend
Joined: Nov 2015
Posts: 30,912
Likes: 4,123
From: Angier, NC
I installed one of these near the carb on my 83 F150 351W and ran the return line back to the the tank. I made a tee with a piece of exhaust pipe and a 1/4" barbed fitting for the return line and installed it in the tank filler hose. This solved my vapor lock problem. I live in South Georgia and it gets hot here in the summer and this truck can idle all day and have no more problems taking off from a red light. Just wanted to share, as this is an easy fix and it works.
Just make sure that small return is at the top other wise it will drain out when off.
Dave ----
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
Thread Starter
|
Senior User
Joined: Jul 2014
Posts: 123
Likes: 0
From: Seattle
I been watching the issue over the last couple days.
truck sits for 3 hours fuel filter is half full, start the truck the filter fills almost full.
shut the truck off wait 2-3 mins and restart.... the filter empties itself and you never see a drop of fuel in the filter but the truck is running......
truck sits for 3 hours fuel filter is half full, start the truck the filter fills almost full.
shut the truck off wait 2-3 mins and restart.... the filter empties itself and you never see a drop of fuel in the filter but the truck is running......
Thread Starter
|
Senior User
Joined: Jul 2014
Posts: 123
Likes: 0
From: Seattle
I talked to Holley about possibly replacing the Holley 4010 with fuel injection and after explaining all the engine rebuild specs a 375 hp engine needs at least 63 GPH fuel pump.
The stock fuel pump is 20 GPH, so I replaced the stock pump with an 80 GPH Holley. The fuel feed line was moved to the outside of the frame then comes straight over the the pump, them the carb feed goes straight back to the driver fender well and around by the brake booster around the cowl then into the carb. I drove it a little and the fuel filter after the pump did stay 1/2 full now where it was empty, but I'm now seeing bubbles coming into the filter almost like the gas is boiling. Even after I shut it down pop the hood its still bubbling. I did upgrade to 1 core radiator to a 4 core radiator which moved the fan shroud back about 2 inches and man is that air HOT..... I'm thinking about putting in a small metal air deflector near the fuel lines.
Anyone figured out how to lower engine bay temperatures?
The stock fuel pump is 20 GPH, so I replaced the stock pump with an 80 GPH Holley. The fuel feed line was moved to the outside of the frame then comes straight over the the pump, them the carb feed goes straight back to the driver fender well and around by the brake booster around the cowl then into the carb. I drove it a little and the fuel filter after the pump did stay 1/2 full now where it was empty, but I'm now seeing bubbles coming into the filter almost like the gas is boiling. Even after I shut it down pop the hood its still bubbling. I did upgrade to 1 core radiator to a 4 core radiator which moved the fan shroud back about 2 inches and man is that air HOT..... I'm thinking about putting in a small metal air deflector near the fuel lines.
Anyone figured out how to lower engine bay temperatures?
Post Fiend
Joined: Feb 2008
Posts: 5,831
Likes: 121
From: St Albert, Alberta
Try adding a quart of diesel for every 10 Gallons this will lower the boiling point of the fuel. Not recommended if you are running cats.
Thread
Thread Starter
Forum
Replies
Last Post
jaymay75
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
3
Jul 10, 2018 01:47 PM
flowney
1973 - 1979 F-100 & Larger F-Series Trucks
5
Jan 5, 2018 12:40 PM
Tyler S
1948 - 1956 F1, F100 & Larger F-Series Trucks
12
Jun 23, 2015 10:54 PM
1975F2504X4
1973 - 1979 F-100 & Larger F-Series Trucks
4
Jun 14, 2015 07:25 AM