vapor lock
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Joined: May 2008
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vapor lock
In oregon we have gone to 10% alcohol all year starting this year. All of the sudden my truck vapor locks after towing and coming to a stop light any time the oat is 65 or better.At 85 degrees I had to wait an hour to get her cooled off enough to get her re-lit. I have tried all that I can think of to keep the fuel cool. That includes: new fuel pump, new high flow water pump, new fuel filter, new and shorter fuel hose (aviation heat shielded), a 1" spacer between manifold and carb and disabling the carb heat to be cold air full time. My truck is a 1978 4x4 with a 400. Elederbrock carb and headers. Summer is coming fast and I really need a solution. Any help would be great.
Senior User
Joined: Feb 2007
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Do you have the stock "cold air intake" hooked up? Originally there was a plenum that came off the radiator support and attached to the aircleaner with a flexible duct.
Do you have any heat sheilding on your headers? They make an asbestos-like tape wrap that you can put on them. It really helps with under-hood temps.
You could also look into an inner-cooler, but that seems a bit overkill.
Do you have any heat sheilding on your headers? They make an asbestos-like tape wrap that you can put on them. It really helps with under-hood temps.
You could also look into an inner-cooler, but that seems a bit overkill.
Post Fiend
Joined: Apr 2008
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From: Big Sky Country
That's a definite yes, they have very small float bowls which make them more prone to boiling all the fuel away after shut down unless you have a phelonic spacer between the carb and the intake.
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Joined: Apr 2004
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I had the same problem with both my trucks. Do you have a saddle tank? Both of my trucks do and the steel fuel line runs behind the tank along the frame rail. You can’t see it with the tank installed. It has a joint where Ford used a rubber hose. Both of mine developed cracks in the hose that allowed air in. I found them when I had the tank out and accidentally moved the hard line and fuel seeped out the cracks. Cracks were not bad enough to leak fuel all the time so it was not noticeable but with the engine running this is under suction so air can be pulled in. Air in a hot fuel line causes vapor lock. Since I fixed them no more problems.
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