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Jack R Eanes · 05-13-2016, 02:17 PM

Hi.I have a 1996 f-53 w/a 460 cid engine. Can anyone give me advise on how to prevent it from vapor locking?(Class A Coachmen)Thanks

TonyMac · 05-13-2016, 03:41 PM

Fuel injected or carb'ed?

cwit · 05-13-2016, 03:51 PM

You will have to cool the fuel down. I never heard of fuel injection with this problem.

luqutus · 05-13-2016, 04:11 PM

First MH a safari with 460. It would vapor lock even though I was told it was impossible with fuel injection. I installed a fan in the dog house above the engine. It cured the problem.

Malamute · 05-13-2016, 05:13 PM

I had ecnoline van and it needed a new fuel pump to stop vapor lock. The old pump would not pump enough pressure to make the pressure regulator bypass fuel back to the tank and allow cool fuel to circulate.
Had the same problem on a Chevrolet Corsica and a fuel pump fixed that also.

TonyMac · 05-13-2016, 05:35 PM

The fuel pump could well be the problem, carb'ed or fi. But vapor lock is just another fuel starvation problem. If it's fi, I'd replace the fuel filter, then the fuel pump, it's likely not heat realted vapor lock, but fuel flow related. If it's carb'ed, I'd do what I've done before, add a bypass line to take fuel from the carb fuel inlet and bypass it back to the tank. This keeps fuel flowing in the fuel delivery system (pump, lines, filter) thereby keeping it cooler. The fuel in the carb is cooled by the airflow of the carb.

Jack R Eanes · 05-15-2016, 07:17 AM

Quote:

Originally Posted by TonyMac

Fuel injected or carb'ed?

fuel injection Thanks

Stevie3508 · 05-15-2016, 07:21 AM

Ford had issues with low fuel pump pressure causing vapor lock. I would check your fp pressure before doing anything else.

OB-One · 05-15-2016, 10:46 AM

The real issue is low fuel pressure. A new or supplemental fuel pump and clean fuel filter should cure the problem.

Cooling the fuel line will also help, but the real issue is low fuel pressure.

mhbell · 05-15-2016, 03:32 PM

I got rid of my 1997 Motor home with F-53 ford chassis and 460 motor because of vapor lock and exhaust manifold problems. Those are the 2 things that were problems on the 460's. On a hot day 90 plus deg F it would vapor lock after a couple of hours running at 50 to 60 MPH on flat and level freeway driving. pulling a long grade was worse. Ford garage would not guarantee that a new fuel pump would solve the problem. The exhaust manifolds would crack or else the rear bolt on the passenger side would come loose or fall out. That was solved with a set of headers. Never could solve the vapor lock problem so traded it off.
Mel

c92vette · 05-15-2016, 08:06 PM

For a quick fix get several wooden spring clothes pins and place them on the fuel lines. The wood acts as a heat sink and pulls heat away from the fuel line. Another thing is to keep the engine clean. Dirt and grime raises the temperatures inside the engine bay causing issues with fuel stabilization and the subsequent vapor lock. This is why adding extra fuel pumps and return lines or fans cures the problem. In the end if you have low fuel flow or pressure your chances of vaporizing the fuel in the feed lines increase as temps increase and cooling decreases. Keep the correct fuel pressure, clean filters, and clean engine in order to dissipate heat build up and you should have no more problems.

Zoom45 · 05-16-2016, 08:49 AM

A stopped up converter will make it do it. Mine had the honeycombed material all broken up blocking the exhaust. It would act like it was starving for fuel and die. You could let it cool down then it ran great till it heated up again. I replaced the converter with a pipe and fixed it.
Zoom45

Nick-B · 05-16-2016, 01:59 PM

The OP's chassis (460 F53) does not have a catalytic converter.
I'm with the low fuel pressure crowd on this. There is a port on the fuel rail along the intake manifold. You can attach a fuel pressure gauge there and test it.
The normal fuel pressure is 32-34 psi at idle depending on the engine vacuum.
The normal full throttle pressure is about 40 psi.