Ok, I am the same guy that had a problem with overheating the other day. We solved that problem because my brother just happened to have a spare radiator laying around. So I installed that and you can't get that needle to move once you get it up to temp. However, I was confident that I could make it to rock springs today but I was thoroughly denied. I hadn't even been out on the interstate for a mile today when my truck began to vapor lock. The temp never moved but the vapor locking just kept reoccurring. Anyways, we pin-pointed the problem, the fault being another one of my ##### ideas. I hated working with that steel line so I ran hose from the pump to the carb. Bad idea!!! So now I have to bend a new fuel line. I was wondering what you guys think the best route would be for the fuel line. It's a 400 and keep in mind that it has a/c. The fuel inlet is on the left side of the carb. I looked at my brother's 400 and his fuel line goes all the way to the other side of his water neck! Is that the best route? It just seems to me like running the fuel line all the way across the water pump, around the water neck and upper rad hose, and then to the carb seems like a bad idea. Also, where should I put my inline filter?

 

Anyways, we pin-pointed
>the problem, the fault being another one of my ##### ideas.
>I hated working with that steel line so I ran hose from the
>pump to the carb. Bad idea!!!

OK explane to me why it's a bad Idea to use Rubber hose in place of the steel line ..

I run 1/2" Rubber hose from the Fuel cell to the Pump and then 1/2" rubber hose from the pump to the fuel reg. 3/8" rubber hose return line to the fuel cell and 1/2" rubber hose to the cool can then 1/2" line to the carb. Never vapor locked on me yet ?

 

It's a bad idea because once rubber hose absorbs the heat, it doesn't dissipate it very fast. At least not nearly as fast as steel line. Besides, the walls on the steel line is much thinner, which also helps with heat dissipation. ShaZam, I really can't tell you why you haven't vapor locked yet. It's probably because you have a cool can but it could also be your location. Vapor lock usually occurs on hot days (and usually at higher altitudes also). It's like 100 degrees out here so it's just too much heat. FYI, this is the first time I have vapor locked so it's not like rubber hose won't work. It's just that when it comes down to it, steel line dissipates more heat faster. Yeah the difference between rubber and steel lines may only be marginal, but I guess I am in the marginal zone because rubber just flat out ain't working. When you pull your fuel line off and the gas is warm with bubbles, it's vapor lock. So I am gonna try the steel line because there is nothing else that could be wrong. The engine temp is closer to the cold side than to the hot and everything else is fine. Ambient temps play a HUGE role in vapor locking and it's just plain hot here. And putting a load on your motor (80 mph up hills) doesn't help vapor lock either. Anyways, it never vapor locked when I had steel line so I'm going back to it. Period.

 

OK

 

I am surprised that the line from the fuel pump to the carb is the one causing the problem. Vapor lock problems usually occur on the suction side of the pump, between the pump and the gas tank. But go ahead and replace that line, I like steel lines too. The less rubber to rot and crack open, the better. If that doesn't fix it, suspect the line from the tank. Look for things like a custom exhaust running too close to the line, or a rerouted original fuel line. I have found with dual exhaust, the only place you can really run the fuel line is on the outside of the frame. And you have to keep it on the outside the whole way up front till you crossover to the fuel pump.

 

I don't think the exhaust is a problem, at least not on my truck. I have this stupid *** stock system that exits in FRONT of the rear wheel on the passenger side. But even if I did have a custom exhaust, it wouldn't be a problem because I have that side saddle gas tank. So the exhaust has to run down the passenger side and the fuel lines are on the passenger side, neatly tucked between that gas tank and the frame. Hey ShaZam, I'm sorry if I sounded a little contentious in that last reply. I really meant nothing by it man. Sorry.

 

I still have the steel line and I am vapor locking anyway. It's that last hill on I25 north of Ft Collins at the Wyoming line, gets me every time. If I have a tailwind and less airflow through the radiator, its worse.

I had an aftermarket filter right before the carb years ago and it caused vapor lock when it got old - took it off.

The air preheat door in the air filter wasn't opening at one time and that caused me to run hot, detonate and vapor lock.

Had the problem when the rubber lines to the dual tank switch got old and leaky.

This time I'm not sure what it is. My intake air hose started coming apart and I took it off a couple years ago. I just replaced it and that helped. The hose is a Mighty Flow 96054 - rectangular at one end and round at the other end.

Replaced the distributor a while back and set the timing with a timing light. Noticed there was no pinging ever. Set the timing by ear and that helped the vapor locking - heat. My timing marks moved - harmonic balancer slipped.

1979 F250 Supercab Longbed 400M - almost stock - Verified 200K maybe more - 60K and 7 years since major work. Hauls lots of weight, if it ain't loaded I'm driving something else.

 

Well guys, I was wrong again. Apparently I am not vapor-locking. My brother went out to drive it home at 10 last night and it still wouldn't go anywhere. He says it isn't getting any fuel. My first suspicion are the fuel filters because I've been having lots of trouble with them clogging lately. They're all fine, however. What I do think it is is that damn fuel tank selector solenoid. I have bought 4 of those things in the last year. One of my tanks is empty, the rear one, while my front one is full. The crappy thing is, when the switch dies on me, it defaults to the back tank. So I'm taking a fuel filter out there and am going to bypass the valve. If that works then I'm gonna stop at NAPA and get a new one. The thing that gets me, though, is those valves cost like $27 a pop. I'm betting they have a warranty on them so I think I'll keep the box and receipt this time. If that doesn't work though, then I have no clue what it could be. Maybe you guys could help. Thanx a million.

 

Well if you don't use the back tank disconnect it and get rid of the switch.....

 

I do use the back tank. It is just empty at present. To get it into town I am gonna bypass the switch so I am running off the front tank. Apparently, my truck doesn't like these solenoids, seeing as how this will be the fourth one. But gotta keep fighting it, that's the only way you can win.

 

One question: Is this a factory Ford tank solenoid? If not, that could be your problem. I have 500,000 miles on an original solenoid that still works fine, even covered in rust!
When your truck dies, turn the key to the 'on' position, and listen carefully with the door open as you flick the switch up and down. You should hear the valve move every time, and even 'feel' it a little in your floorboards. It coul;d even be a faulty dash switch. I get junkyard Ford parts whenever I can, 'cause in my past experiences, most everything in the junkyard actually works like new! (Only in the Ford section... Don't try this in GM!)

Mark



https://www.ford-trucks.com/user_gallery/displaythumbnail.php?&photoid=5362&.jpg
Ford started it; Ford will finish it!

 

Do you think they still sell them at Ford? I have to keep buying them from NAPA.

 

I don't know... Been buying from junkyard for so long I haven't been in touch with The Motor Company...
Maybe the new trucks with dual tanks have a similar type switch? I doubt it wouldtake much to make it fit if it isn't exactly identical... Give 'em a call tomorrow morning, just for a joke! They may have one...
Mark


https://www.ford-trucks.com/user_gallery/displaythumbnail.php?&photoid=5362&.jpg
Ford started it; Ford will finish it!

 

Trinogt-

You like the salvage yard parts too:-)

 

Well I feel like a huge ##### now. We went out there and tried to get my truck running and we found the problem. A clogged fuel filter. AGAIN. But I put 3 filters in the line now so it shouldn't ever do that again. I also just replaced the hose with a steel line anyways because I anticipate the heat is going to get to my truck. I'll tell you, bending a new fuel line when you don't have an old one for reference is a huge pain in the ***. A tip for any of you that ever have to do it - take your power steering bracket (and A/C Idler bracket, if so equipped) off. That way you have a straight shot at the fuel pump and the line goes in easier. However, remember that there is a bracket that needs to go on and bend accordingly. It took me forever but it was worth it - my fuel line doesn't touch anything, it's fully floating. And there is quite a bit of air around it too. So I don't think I will vapor lock although my bro says that it happens to everyone once in a while. I just hope not me.