Vapor Lock?
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Freshman User
Joined: Jun 1999
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Vapor Lock?
I have an 87 F-150 Extended Cab 302 EFI. Everyone once in awhile I will have problems starting it. I have a fairly recent Ignition Control Module and Ignition Switch, plugs, wires.
Last two times I had problems starting, I remembered that someone had mentioned something about vapor lock. I eventually opened up both gas tank caps and the truck started.
My question is, "What is Vapor Lock" and could this be the cause of my truck not starting sometimes?, or should I look at something else?
Last two times I had problems starting, I remembered that someone had mentioned something about vapor lock. I eventually opened up both gas tank caps and the truck started.
My question is, "What is Vapor Lock" and could this be the cause of my truck not starting sometimes?, or should I look at something else?
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Joined: Mar 2000
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From: Craig
Vapor Lock?
Vapor Lock is when the fuel in your lines boils. In order for the gas to be pushed from the tank to the cylinders, it must be in liquid, not vapor form. If it is in vapro form, you are really just pushing air (which doesn't burn very well). Does your truck do this in the morning when it is cold, or mostly when it has been run for a while and shut off? Another thing that might be considered, check the vent to the tank. I don't know, but it may also cause the fuel to be pulled back to the tank (Vacuum). When you release the pressure by opening the cap, it allows the fuel to be pumped again. I doubt this is it, but when I got thinking about it, it sounded like an option. I have heard of this happening on vehicles like beetles and motorcycles, so it could be possible.
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Joined: Jun 1999
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Vapor Lock?
Thanks for your post, didn't think anyone knew about this or that i was just asking a stupid question. It does/did this after i've been running for at lease 10 mins or so, but after thinking about it and all the possible fuel pump problems that have been posted, i'm just wondering if I have a fuel pressure problem. When i first start in the morning, it is harder to start. After started for the first time in day, it is easier to start, unless I get what I thought could have been "vapor lock". Thanks again, Roger
