vapor lock

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ronnyd8719

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Joined
Apr 1, 2007
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11
In April I purchased a Damon Intruder. It is a ford chassis with a 460 engine. I when on a trip to the rockies and it ran well in the cooler areas, but then I got to Utah and the heat and the alt. caused vapor lock. Can anyone give me a fix to this problem.
Thanks for the help.
Ron
 
What year chassis is it? Vapor lock is no longer a common problem and the causes are different depending on the type of fuel system, e.g., direct fuel injection, throttle body injection, carburetor, etc.

What are the symptoms that cause you to say it is vapor lock?
 
It is a 1997 year. In the hot weather and high altitude the thing would run great in the morning and then I would go down a hill and give it gas and it would sputter and die. I could not restart it till cool weather. Like the next morning and that is a problem. I had to have it towed once and the mechanic did not know what was wrong and wanted to change the fuel pump. I did not let him and the next morning the thing started right up. It is gas and fuel injected.
 
Good chance it might be the fuel pump but I'd change the in line filter first.  The 97 should have one. nest to the frame on the left side.  JMO
 
I changed the filter and it did not help. It may run 300 miles or 100 miles and when it got hot it would act up.
Thanks
 
Is it using any water or losing water, boiling over or just showing hot.  with the High altitude you mentioned, Timing could even be a factor.  Radiator cap or Fuel cap.  There are lots of variables.  What is causing the Temp to rising? is the 1st question.  Are the fins on the A/C coil in front to of the radiator clean and well as the Radiator.  Any of the above can effect the temp and possibly any combination of all.  Does the fuel act like that when you are at lower levels. When using the Dash A/C does it act the same.  Trying to decipher what it is.  Sometimes hard to do from afar.  As Gary says we're all in the dark until we know what carberation you have or injector system. From the info here it's just a pig in the poke and pulling straws.  JMO
 
I don't know if this will help, but a Banks horsepower package for gas was install when I purchased the motorhome. There is no different with the air or not. The water temp would go up a little about 10 degrees of normal. It was not like it was hot to worry about. The transmission would run about 15 degrees above normal. What was causing the heat was the air temp out side (100) and climbing long steep grades which kept the transmission in lower gear and make the engine turn more rpms without speed to pass though the radiator to have the cooling it would get without the steep grade. The temp would go down a Little as I would go downhill. I could get it to start, but the rpms would not get above 1000 and I had to keep pumping the gas pedal to keep it running. If I stopped the engine would kill and at 1000 rpms the transmission would not pull the motorhome and up hill was bad.
How do you tell the type of injection system. I though the model and year would tell that. Is there a place to look for the type of injectors.
Thanks Ron
 
I needed to ad that I drove home from Santa Fe, NM to Louisiana without a bit of trouble, but I was at lower alt. about 3000 and less the problem is not a problem anymore.
Thanks Ron
 
Ron,
I doubt it's as much a vapor locking problem as a fuel/air mixture in high heat and high altitude?  Vapor locking was taken care of by Ford and Chevy in the late '80s/early '90s.  Your '97 Ford 460 has a port injected fuel system that was one of the most efficient system in the time period.  What seems to be happening is the thinner air, combined with the hot vapor gases into the chamber is not the right mixture and therefore, not the right "fire" for the cylinder.  This mixture is supposed to be regulated by the O2 sensor and adjusted by the computer module.  Could just be a bad sensor, or a problem with the computer.  One more area...the computer.  Look in your Ford owner's manual about resetting the computer.  If memory serves me, if your battery was disconnected, or some other thing happened, you were required to take it to a dealer that would "reset" the settings which was simply driving it at 25-30 mph for about 6-7 minutes?  I don't remember all the details, so find a "seasoned" mechanic who would remember this.  Good luck
 
Could be a heat problem @ the computer.  I would have that checked out soonest.  Let the mechanic know about the heat.  It will probably be very hard to recreate the conditions but maybe an extra cooling fan would help.  Like from in front of the radiator to dump directly onto the computer.
 
FUEL PUMP

My experience.  Drove my '94 class B (V-8 351) almost nonstop from SE Louisiana to the Painted desert.  Started having the same problem.  Missing and chugging when I needed power.  Stayed overnight.  Ran great the next day until I got close to Grand Canyon.  Same problem.  Camped a couple of days then ran great until I got just past Kanab, Utah on our way to Zion NP.  There it died in the worst place.  Trooper called a tow truck.  Storm came by and cooled the air.  Tow truck arrive 2 hrs later.  Engine cooled, started and ran great back to Kanab.  The truck operator says this is common in his area with Fords in the summer.  The fuel pump isn't pushing enough fuel to keep the fuel cool and liquid.  They changed the pump the next day and haven't had a minutes problem since.  Wife and kids had a great time in a real bed at a hotel.

Scott
 
Our friends had a Ford Focus that had the same problem.  Ford service indicated it was a common problem on many Fords of that vintage.
 
I've seen this Ford fuel pump issue mentioned several times, although I remember the mention that in '96 and later models they improved the design... so that shouldn't affect ronny's 1997 Damon.  But for pre-96 models like my 1994 Thor, should I replace the fuel pump just as a maintenance item to hopefully prevent these issues?  If I order a new one, will I get the new design or is there a pre-1996 and post-1996 version (meaning that even a new one in my '94 would still be the older, less reliable design)?
 
If you order a new one, you will get the revised design, which replaced the previous version.  But yours may have already been replaced - most pre-1996 460's have already suffered fuel pump failure and have been fixed. The rule of thumb was that the fuel pump failed at around 35,000 miles. The pump output just got weaker and weaker until finally you began to have performance problems.

It's possible that Ron's 97 is on an early 96 chassis - hard to guess since model years often change several months before the calendar changes and RV builders often have chassis stockpiled for later use as well.

But it could be just a weak fuel pump - it happens.
 
I didn't indicate the Focus had a 460 just a Ford fuel pump that was in need of replacement AGAIN.  Living up to the term Fix Or Repair Daily. :D
 
Knew what you meant but had to throw it in the fire  LOL  Also  First On Race Day.
 
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