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EFV-8 Club Forum / General Ford Discussion / vapor lock

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Posted By Discussion Topic: vapor lock -- page: 1 2     chucky 05-29-2023 @ 4:10 PM reply profile send p.m. Member Posts: 82 Joined: Jan 2022 Does anyone have any thoughts on preventing vapor lock. Thanks... ford38v8 05-29-2023 @ 5:28 PM reply profile send p.m. Senior Posts: 2758 Joined: Oct 2009 Oh boy. Well, let’s start off the conversation with a collection of wooden clothes pins on the fuel line under the hood. Next traditional fix was to squash half a grapefruit onto the fuel pump. Better than both of those, run without a hood. An electric fuel pump acknowledges the reality of modern fuel. And then, what’s old is new again, a fuel return line to the tank keeps the fuel moving and liquified. Alan carcrazy 05-29-2023 @ 10:14 PM reply profile send p.m. Senior Posts: 1650 Joined: Oct 2009 One thing to try is to wrap the fuel line with a layer of fiberglass cloth covered by a sheet of aluminum foil. You can use zip ties to keep the foil in place. Jacques1960 05-30-2023 @ 3:44 AM reply profile send p.m. Member Posts: 201 Joined: Aug 2020 Are you sure it’s not a bad coil ? Symptoms can be very similar. chucky 05-30-2023 @ 4:56 AM reply profile send p.m. Member Posts: 82 Joined: Jan 2022 Thanks for the help guys, I have a rebuilt skip haney coil. Would running an electric fuel pump solve the problem? trjford8 05-30-2023 @ 7:25 AM reply profile send p.m. Senior Posts: 4214 Joined: Oct 2009 An electric pump may help, but first make sure your gas tank is nice and clean. One time I thought I had a vapor lock problem. As it turned out there was a piece of crud (small piece of gasket sealer) floating around in the tank. Every so often it would get near the pickup tube and shut off the gas. If I waited it would dislodge itself and the car would start back up. I would check the inside of the tank before doing anything else. TomO 05-30-2023 @ 8:15 AM reply profile send p.m. Senior Posts: 7250 Joined: Oct 2009 Excerpt from my V-8 Times article: Insufficient fuel delivery: This condition shows up when driving at highway speeds as a miss or the engine dies. Vapor lock occurs when the fuel pump output pressure is very low and the engine is hot. It is much rarer than commonly thought. Most cases of suspected vapor lock can be attributed to another problem such as a weak coil or condenser, but can be caused by a weak fuel pump. To determine if you really have vapor lock, remove the air cleaner and look in the bowl of the carburetor, while operating the accelerator linkage. You should see two streams of gas in the carburetor if you don’t, you have a fuel pump problem. Fuel pump pressure is controlled by the return spring under the diaphragm, too little pressure means the spring is weak, too much pressure means the wrong spring was used. Pressure should be between 1.5 - 3.0 lbs at all engine RPMs. Too much pressure will not allow the float to control the amount of fuel in the carburetor bowl, low pressure will affect fuel delivery. To check fuel delivery, you need a graduated 16 ounce or larger container to determine the amount of fuel delivered in a measured time. Disconnect the fuel pump line from the carburetor and direct it into a graduated container. Crank the engine long enough to get 2 ounces of gas in the container and then continue cranking for 15 more strokes of the pump. The pump should have delivered 6 more ounces of gas. Insufficient fuel delivery can be caused by a vacuum leak, plugged flex line, worn pivot in the pump arm, stretched diaphragm, plugged fuel line or tank pickup, plugged tank vent or wrong gas cap or a worn push rod. Following the above instructions should help solve your problem. Tom 1931 Flamingo 05-30-2023 @ 9:33 AM reply profile send p.m. Member Posts: 386 Joined: Nov 2019 Bad gas cap?? Paul in CT Drbrown 05-30-2023 @ 9:34 AM reply profile send p.m. Senior Posts: 570 Joined: Nov 2013 I currently have similar problem but think its my coil. Historically I have not experienced vapor lock. I have a vented gas cap. I have a refurbished "Points" distributor w/cap, rotor etc and Bosch coil from Charles S. and new gas tank, fresh gas, electric pump as start/back-up, insulated gas line to pump, rebuilt engine pump and carb from Charles. When cold, engine starts and runs great. The engine runs fine at any speed. However after I drive it locally and then let it idle a bit, it quits and will not try to restart. The engine is not overheating - runs at 165 degrees. However, at that point the Bosch coil is very hot - can not hold finger on it. As a spare I carry a Bubba's Pentronic electronic distributor and his coil with built-in resistor. So I immediately replaced the Bosch coil with Bubba's and the engine started right up but was coughing and gaging terrible. I had to run the engine at high RPM to keep it going. So shut it down not wanting Bubba's coil to damage something. The engine CAN run fine without defects etc so I think distributor points, cap, rotor, condenser and wires are okay. Waiting to hear opinion from Charles before buying a new coil. This message was edited by Drbrown on 5-30-23 @ 9:42 AM 37RAGTOPMAN 05-30-2023 @ 2:57 PM reply profile send p.m. Senior Posts: 1958 Joined: Oct 2009 did you try a fuel sample to make sure there is no water in it ? or dirt, is the front to real line new or real clean? is the flex line in good condition, not leaking air in ? check for fuel pressure and OUT PUT of fuel pump did you try cleaning the carb, flush it our with GUM OUT you never said what year car you are tryig to fix, this would help. hope this helps 37Ragtopman

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