Vapor lock on Ford Grain Truck

I've been having this problem off and on in the summer. Today I was hauling grain and it quit at the loadout at the terminal. I let it set a half an hour then it started up. It tends to do the vapor lock when idling or raising the box to dump. I live in Minnesota and today it was around 70 degrees. Is there any fix to help this. It is ethanol 10% blend gas. Would premium help, or some type of additive? I've heard putting a small amount of diesel fuel in could help. Any ideas or thoughts are greatly appreciated. The engine is a 1982 429 Ford. Thanks, Denny

We used to run Ford straight trucks that had the same problem. I mounted electric fuel pumps back by the tanks or inside the tanks which really helped. School buses had insulated fuel lines back then. Good luck.

I removed the mechanical pump and blocked off the hole.

A carb will heat soak on an engine and the mechanical pump will also heat the fuel. With the OEM pump and carb there is not much that can be done.
I would put an electric fuel pump on the firewall, or near the fuel tank. Then I would re route the fuel line so it goes directly to the fire wall and down. Putting heater hose over the fuel line insulates it further.
Make sure the carb heat stove system on the air cleaner is not turning on, allowing the intake to draw air from around the exhaust manifold. My preference is to put a "summer" aircleaner on it with a snorkel that draws cold air from beside the radiator or other non heated air.
Many times a ducted fan can be used to direct cool air on the carb from the front. This can be switch controlled from the cab to allow situational use.
Winter grade gasoline is still in the pipeline and tanks at gas stations. It is substantially higher in volitiles and will vaporlock much easier.
I know of no fuel solutions or gimicks that work.
I have used all of the above methods at one tome or in combination to cure (successfully) vapor lock. These are not snake oil magnet on the line garbage. Jim

Yea there is a cure for vapor loc. Vapor loc happens in the fuel line BEFORE the carb. There was a kit way back when i worked for Ford and also Chrysler . This kit was a fitting that went in the fuel line before the carb and had a small barb fitting that you place a small fuel line off it and it ran back to the pump on the suction side . This allowed fuel to move with out being held in the steel line and cook or boil when the needle was closed due to a full fuel bowl . The barb off the fitting had a small hole that allowed the fuel to flow with out causing a starvation problem when you were at W O T . One other thing that also maybe a problem is the power valve as more then likely it has a holley carb and even if it has a Motorcraft carb they too have a power valve and this could be leaking causing you to loose fuel in the float bowl. Many years back i had a 56 Ford that use to give me fits when it got warm out and we tryed all the old tales of close pins , insulation on the fuel line rerouting and nothing helped Till i did the bypass thing years before Ford or Chrysler came up with the bypass deal. That fixed the problem .

"Vapor Lock" is shadetree speak for "I need a fuel pump and just don't know it yet". :>)

Allan

(quoted from post at 19:39:20 03/27/12) Yea there is a cure for vapor loc. Vapor loc happens in the fuel line BEFORE the carb. There was a kit way back when i worked for Ford and also Chrysler . This kit was a fitting that went in the fuel line before the carb and had a small barb fitting that you place a small fuel line off it and it ran back to the pump on the suction side . This allowed fuel to move with out being held in the steel line and cook or boil when the needle was closed due to a full fuel bowl . The barb off the fitting had a small hole that allowed the fuel to flow with out causing a starvation problem when you were at W O T . One other thing that also maybe a problem is the power valve as more then likely it has a holley carb and even if it has a Motorcraft carb they too have a power valve and this could be leaking causing you to loose fuel in the float bowl. Many years back i had a 56 Ford that use to give me fits when it got warm out and we tryed all the old tales of close pins , insulation on the fuel line rerouting and nothing helped Till i did the bypass thing years before Ford or Chrysler came up with the bypass deal. That fixed the problem .

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BEFORE the carb".....yes, BEFORE the fuel pump. Pump can force vapor thru line & out float valve, but it CAN NOT suction vapor. If truly vapor lock (a catch-all phrase, I'm afraid), then the fuel line ahead of pump needs the insulation/cooling. Cooling is the more important since heat from block conducts to pump & from pump to inlet line & fuel in line.

thing that makes it worse is now you are still getting winter blend fuel which will make the vapor lock issue worse, usually april or may before they switch, but putting an electric fuel pump back as close to the tank as you can will usually cure it.It is on the suction side of the pump where the problem is. Same principal as radiator they put pressure cap to raise boiling point, vacuum lowers boiling point.A demonstration of this can be done if you have a vacuum pump and a jar, put a fitting on the lid, add tap water, put lid on tight and start sucking down into a vacuum, water will start to boil. Bet somebody a beer to make it interesting, I can boil this water in this jar without any heat source. Then bet them another beer you can make car, truck, tractor , whatever run without a coil wire, just put a vacuum hose from coil to distributor cap where the coil wire goes, another free beer. Of course it has to have coil, distributor cap type ignition to run this scam.

Vapor lock can easily be caused by restrictions between the fuel pump and the fuel tank. If the fuel pump sucks against a restriction, it creates a vacuum. A vacuum lowers atmospheric pressure and things that would not normally boil will...i.e. fuel and once your fuel is full of air, it doesn't have the density to run your engine and it will stop. Do you have a filter between the inlet to the pump and the tank? If so, remove it. Or, is the inlet screen in the fuel tank clogged up due to old fuel and varnish which has accumulated over the years? Clean it out. BTDT

Mark

When it stalls next time, don't wait the half hour, carry a bottle of cool water, and pour some over the fuel line, she'll start right up.

I have seen people put wooden clothes pins about every few inches to act as a heat sink. They said it works pretty good. The wood absords some of the heat off of the line.

I agree with Allan. If it is an older Ford with fuel pump it will vapor lock when it gets weak. Simple to change and the hotter the air temp gets the more it will lock up. BTDT

Its been in the 80's here the last few weeks and I have ran across this issue 2 times lately... 63 chebby 327 and a 2001 Jeep Cherokee,,, I Goggled it and it seams to be a common problem on the Jeep (jeeps have a lectric fuel pump),,, but I have seen the addition of a lectric pump help this issue on a boat,,, I was looking for some foil backed insulation to go in the floor of my tow truck,,, stopped buy the upholster shop and told him I was headed off to get a roll of header wrap and how expensive it was..... He dug in his pile and came out with a big arse roll of asbestos that looks like fiber glass mat... I was happy to get a 1' by 4' piece free 8) came back and rapped the fuel rail on the jeep and its fixed... I think we are gonna see more of this drunk fuel issue,,,, The 63 If you idled it long the hot light would come on,,, the temp was 230 and I noticed the fan clutch was not working as it should,,, a new GOOD fan clutch and the so called vapor lock went away...

Remove the fuel pump from the engine, block off with a plate, and put an electric fuel pump(s) back at the tank(s). Unlike the original OEM mechanical fuel pumps, electric fuel pumps are pushers, not pullers. There are a wide variety of aftermarket manufacturers, they have come a long ways since they first began being popular in the mid to late '80's, and these days I can't think of a gasoline road vehicle that doesn't come with one, inside of the tank(s).

One way or the other, fuel pump.

Good luck.

Mark

I didn"t remember that Ford still made 429"s in 1982. Does it use a mechanical, on the engine fuel pump? I have an 84 F250 with a factory carburated 460. It has an electric fuel pump for each of the two gas tanks and a setup that changes fuel flow from one tank to the other. It also has a device in the fuel line near the carb that cycles some of the fuel flow back to the tank via a return line. I assume that the device was put there to avoid vapor lock, as it is in the highest point in the fuel line. I have never had any vapor lock problems with that truck. I don"t know how such a device would work with a mechanical pump, but it sure seems to work well with the high flow electric pumps.

Something we used to do while waiting in the long Summer lines to get a turn to drag race was to open the hood to vent the underhood heat a little better. We also hand pushed our cars in the lines, but that wouldn"t be nearly as easy with a loaded grain truck!

Opening the hood would cost nothing, and it might help. Just don"t forget to close it. Rigging an electric pusher pump, a vapor separation device and a return line would probably eliminate the problem, but it might end up costing several hundred dollars.

I doubt that using premium gas will help a vapor lock problem, but trying some wouldn"t hurt. I know of no additive to prevent vapor lock. I remember guys wrapping their fuel lines with many layers of aluminum foil as a kind of heat shield, but I don"t know if it actually worked.

Vapor lock is a hassle that I don"t think most people have to worry about anymore with fuel injected vehicles. But I sure remember those hassles, and I think modern gasoline makes it even worse. Good luck!

Back in the early eightys, the company I worked for bought 2 F800 Ford's one with a 429 and the other with a 370. We eventually put electric in-line pumps, and rubber hose down the middle of the engine bringing the fuel in from the back. plus a quart filter on the firewall. These trucks were Fuel trucks and sat and pumped as much as they were driven. The local Farm Service was trying to spread and spray with the same kind of trucks. They changed theirs also. Eventually Airtex Products came and looked at them. They made the mechanical pump and the Electric pump. Yes Alcohol does make it worse. Chevy put headers on some of their 427's trying to help this. Vic

We have a 1979 f 700 had the same problem with E 10 that is the only vehicle we ever had do it . We made a tin shield for the fuel pump because it is right by the manifold and it helped .But still on very hot days it would vapor lock. We started filling it with regular and it helped but I think the electric fuel pump would solve the problem.

Ive owned 8 flathead Ford v8s.They were good at vapor lock.A cloth bag with ice on the fuel pump will cure the problem.I have one that will vapor lock with an electric pump.A weak pump and vapor lock are two different animals.Ive had chevys dodges, plymouths, ramblers, studebakers that ran fine in the hottest weather.The v8 Ford was a crap shoot in hot weather.

Have you tried a glassbowl fuel filter turned upside down in line between pump and carb. Used to work for me on 292 & 312. You don't even need the filter that comes on bowl act as an accumlater for vaper and let gas pass thrugh.

Jim's comments are on target. One thing that has helped me solve this problem is to install an insulator/spacer block between the carb and the intake manifold. Mr. Gasket used to make this item to fit common carb bases. Also, if hot air from your fan is blowing directly back towards the carb, you may be able to install a baffle to direct it away from the carb. I have found that installing an electric fuel pump inside the frame rail under the truck, and then insulating the fuel line the rest of the way with a reflective barrier like foil tape on the outside will also help. Jack

I drove two different Ford school buses, an 86 with the 370 and an 87 with the 429. Neither ever vapor locked with the in-tank pump. Sometimes it was so hot I wished they would. Go to a bus salvage joint and get the unit out of a bus.

On a side note, that 429 is a hot running engine. The mechanics hated those things when it came manifold time as that always meant pulling the heads. They just cooked those bolts to nothin and the engine sits too low in the rails to repair installed. The 429 seemed to cook ignition modules quicker, too.