need help possible vapor lock

[NYLES]

I think id part with the vapor tank and or come up with a better tank vent

 

[dan73]

If the caps are venting should it be bubbling up in the vapor tank? (getting new caps today)

 

[NYLES]

Only thing that makes fuel bubble it is getting hot SOMEWHERE? Imguessing your still runnning a carb and somewhere a line is close to a heat sorce. Could even be at the carb getting heat from the intake?

Maybe try getting rid of the aluminum spacer and get a phnolic one

 

[dan73]

Only thing that makes fuel bubble it is getting hot SOMEWHERE? Imguessing your still runnning a carb and somewhere a line is close to a heat sorce. Could even be at the carb getting heat from the intake?

Maybe try getting rid of the aluminum spacer and get a phnolic one

who makes one for a 2bbl?

 

[72_EB]

http://www.summitracing.com/parts/SUM-G1406/

I have been meaning to try this one, but haven't yet. My aluminum Mr. Gasket has been giving me a little more trouble this summer (manifold heat as mentioned). All this crappy Ethanol mixed fuel is not helping our carbs either. It boils faster. Let us know if you try it and it helps.

 

[72_EB]

I'd ditch that thin upper paper gasket though. Napa has a good replacement 1/4" thick gasket like the stock Ford one. I'll dig up a part #.

 

[pierr]

Not trying to be a smarta$$..but have you checked the float level in the carb?? Just for sheetz & giggles..I'd check it & maybe raise it..a little anyway. Then I'd insulate the fuel line within the engine compartment. What's the fuel pressure doing while it's running? If you don't have a guage on it.. I'd rig a cheap one near the carb to monitor it before throwing any more $$$ at it.Pierr

 

[dan73]

Not trying to be a smarta$$..but have you checked the float level in the carb?? Just for sheetz & giggles..I'd check it & maybe raise it..a little anyway. Then I'd insulate the fuel line within the engine compartment. What's the fuel pressure doing while it's running? If you don't have a guage on it.. I'd rig a cheap one near the carb to monitor it before throwing any more $$$ at it.Pierr

well as for the float i can run the truck wide open for miles as long as the sun is down so I dont think that is the problem. I don't have a gauge

 

[dan73]

I've owned this truck for 10 years, never had this problem until I tore it all apart for restoration. When I was replacing the floor under the vapor tank I tried removing the tank. The four lines were stubern and I could only get one of them off. So I worked around it. Im sure the one I did get lose is where the gas smell is coming from. Am I right in thinking that it wouldnt suck air at the vapor line.. just a vent right?

 

[Rustytruck]

Depending on what year truck you have, the newer models have sealed tank caps. The vent lines hook to the recovery bottle the recovery condences vapor to fluid and drains back to the tank. Excess vapor goes to the charcoal canister. Canister has fresh air inlet and controled exhaust to the air cleaner. There is also on some models of vacuum cans vacuum ports to the intake manifold so that fuel vapor inside the canister is not released unless the engine is running. This is a simplified version depending on year of Bronco and air cleaner systems used. I had a problem once where the gas tank in the sun would pump fuel through the vents to the recovery bottle to the other tank and over fill the tank on the other end. One way to solve venting issues it to look at the vent valve in the gas tank and make it so it properly vents for you. If you drive the truck and the gas tanks pressurise then you have a venting issue. If the engine is running and the tanks have pressure then you have a venting issue. If you park the truck in the sun with full tanks and your engine isnt running there should be pressure in the vent system unless you have an open charcoal canister system where you could acutally fill the charcoal canister with fuel and have it over flow. It is a relatively simple but complicated system since Ford didn't use exactly the same set-up through out the years. Most Bronco owners have disconnected or modifyied the system due to frustration with it ultimately ending up with a modifyed simple vented cap or filler neck. Maybe not good for the environment and not legal but doesn't mean its not done. Most documentation for this system hasn't surfaced in the real world and most repair manuals just slap a generic system pictures and leave it to that. On my Bronco when I went to 3 gas tanks many moons ago I had to deal with this venting system and learned what frustration was really about. At least when I started my venting was complete and functional. How it ended up is a whole other story.

 

[dan73]

the truck is a 73, everything is still hooked up except the line from the canister to the air cleaner

 

[dan73]

Ok replaced both gas caps. Drove it approx. 100 miles in 100 degree heat Saturday, ran great! 3000 rpm no problems. I get up at 3:30am today head to OKC. drive 10 miles, dies. I pull the suction line off the fuel pump, very little gas runs out. put it back on, fires up. I drive another 20 miles, stop to get gas. Drive 3 or 4 blocks and dies. Get back under it pull the suction line. Bone dry. I blow into the line then fuel runs out. Hook it back up, drive 30 miles to air port and all the way back home with no issues. Are there check valves in the vapor tank? I don't know what else to do.

 

[dan73]

bump
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[72_EB]

Are you still getting boiling/bubbling at the vapor tank on the driver's bedside? If you are, the fuel is still heating up somewhere and it is not a vent issue. Certainly possible you have a combo of issues though. If you have the stock charcoal canister from '73 it could be saturated with fuel and not venting. The only check valve I know of on that line was in '76 and '77 with the later firewall mounted charcoal canister. There was a check valve on those on the frame rails in late '76 and on '77. The ones before had bent fuel lines going along the floor supports to prevent liquid fuel from reaching the charcoal canister, but after 40 years, fuel can still get up there and saturate the old charcoal canister.
Do you know what model # Carter pump you are using too. The ones that are rated from 1-4 psi are usually not enough to feed to the system alone, but I have used them in the past as a back up pusher pump to click on during really hot days. A good working mechanical pump is usually all you need with a stock system though, although I've had good and bad new ones. I've had good luck with the Airtex brand available at Autozone lately.
Anyway you can get us some pictures of your setup? That might help us see what is going on too. Maybe electric is mounted too far from the tank.
Let us know if the boiling fuel issue remains. Sorry for the long coffee reply this morning.

 

[dan73]

Didnt hear the boiling yesterday morning. the pump is the one that looks like an inline filter. Right now it is mounted near the selector valve because i installed the front tank. but I have had it mounted 6 in. from the rear tank with the same results

 

[72_EB]

You know another quick thing to check would be to make sure your pump is getting a full 12 volts. I had a weird low pressure issue once that turned out to be low voltage to the pump. It is best to run the power through a relay to make sure that it gets full juice.

 

[dan73]

Thought of that but have no way to check it

 

[72_EB]

A handheld digital voltmeter might be a good investment if you can't borrow one. The Sears ones are pretty cheap but tough and good for basic electric.
Has to be in my top 5 tools used on my EB. Go get one.