FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: fryedaddy on March 08, 2016, 04:34:37 PM
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i have owned my 66 caliente for 33 years,i have put 4 different FEs in it and i have had vapor locking problems with every engine,mostly in warmer weather.heres what it does. you can go for a ride and get it up to temp,park it for a few minutes or a little while.when you get back in it and go down the road it acts like its running out of gas.then after you drive a little it clears out
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Do you use the factory type fuel pump or electric? A good electric will help. The factory steel line runs cooler than black rubber. The best way to stop the vapor lock is with a bypass system and return line to the tank. The gas now days is prone to vapor lock.
Nick
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it has a carter mech. factory type.it must be vapor locking from the carb to the tank because it takes a minute to get gas back up to the carb.
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The vapor lock is usually from the pump to the carb, that's where the most heat is.
Nick
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if the fuel pump is heating up could the heat push fuel toward the tank. it takes almost a full minute to get the carbs working
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How old is your fuel pump? Have you check it for pressure? Couple of ways to do this, just be careful.
Lack of a pressure head can, all by itself, show symptoms of stalling. One way to tell is taking it our for a ride and nailing it hard through a few gears. A weak pump will lean that mixture out and the engine stops pulling hard at top rpms especially. Often it's hard to diagnose true vapor lock versus a weak pulse of fuel.
Also if the car has the OEM sock in the gas tank, it could have become clogged. Take off the line to the fuel pump, crack the gas cap a tad and blow about 20PSI into the line under the hood. Careful here, outside, no smoking! If the car runs better, time to drop the tank for a thorough cleaning.
Finally, any original rubber in the fuel lines should be replaced as guys often skip the suction side (tank to fuel pump) and miss the fact that even a tiny pinhole or crack that doesn't even leak in the rubber lines kills the vacuum from the pump and leans the carb out.
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all of the rubber lines are new even the little one at the tank.i have noticed some trash in my filter and my old carb went south ,maybe clogged.i dont think the pump is weak because i have run it hard for 10 seconds or so at wot,and it didnt lean out,and when i loosen my line at the carb it blows gas out with a lot of pressure
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Your original post describes classic vapor lock. Do you have headers that might overheat the fuel line by the frame? An electric pump near the tank will help a bunch, they push fuel better than they suck.
Vapor lock is not really a lock, it just don't pump or fill the carb for crap. It takes a minute to get it out after a warm shutdown. To double check it the next time you have a warm shutdown, pop the hood and leave it open until you are ready to go.
Nick
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I live in southern Ga. It's hot.
Had this problem and many others that were heat related.
Solution:
-Block Exhaust crossover in intake
-Phenolic spacer under carb (even 1/4 inch it good)
-Isolate fuel line from engine heat as best as possible
-electric fuel pump (this one isn't required but it does help)
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all of the rubber lines are new even the little one at the tank.i have noticed some trash in my filter and my old carb went south ,maybe clogged.i dont think the pump is weak because i have run it hard for 10 seconds or so at wot,and it didnt lean out,and when i loosen my line at the carb it blows gas out with a lot of pressure
Great, then since you have eliminated the other suspects, it is vapor lock.
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I have a 78 F-150 with a 460. It was pretty prone to vapor lock. Sometimes it got so bad, when I'd stop for a toll booth on the highway, then take back off at a moderate speed it would die out. Usually it would refill before I had to pull over. One of the things that would help the situation was to change the fuel filter. There must have been quite a bit of sediment in the tank of that truck as I went through more fuel filters in that truck any other vehicle....still do. I would guess the clogging filter which was near the carb would slow down the fuel flow allowing it more time to warm up in the pump and line to the carb. Optimally, the best course of action would be to put a fuel pressure regulator right before the carb that has a return line to the tank.
Another problem I have is with my 69 Cougar 351w 2v. After driving on the highway then stopping and shutting off the engine it will heat soak and you can see the fuel boiling right out of the boosters in the carb. I run a 195 thermostat. Perhaps dropping to a 180 might make the difference. My belief on this is the fuel in the line between the pump and carb heat soaks and is putting enough pressure to blow the needle off the seat. One of my thoughts on fixing this was to Tee into the line just above the pump. From this tee would be a very small restrictor, maybe .062" to .093". This would feed into the line right before the pump. This would allow any excess pressure to feed back into the open fuel line when an over pressure results from heat soak. The pump will outflow that small oriface by a longshot to feed the Autolite 2100 carb. I haven't done this mod yet. In an effort to keep the bypass as discreet as possible is why I'd do it just around the pump. The car was restored to stock and I don't want any excess hoses, pressure regulators or gauges under the hood.
Mark
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I live in southern Ga. It's hot.
Had this problem and many others that were heat related.
Solution:
-Block Exhaust crossover in intake
-Phenolic spacer under carb (even 1/4 inch it good)
-Isolate fuel line from engine heat as best as possible
-electric fuel pump (this one isn't required but it does help)
Everything Drew said.
My old Falcons were really bad about this with the intake sitting on top of the exhaust manifold. It can get you in bad trouble sometimes.
I try not to hug the fuel line close to the engine, but keep it a little more out in the air. Keeps engine heat from soaking into it. Also, if you're at a place where it's ok to do it, pop the hood open a bit when you stop, to let the heat out; those compartments are tight and there's no way for heat to escape.
And if you have headers, make sure the line isn't close to them.
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thanks,a lot of good ideas.clean filter,fuel lines away from heat,electric pump,open hood,etc..
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"Vapor lock" is typically liquid fuel turning to vapor (boiling). Any reduction of pressure will lower the boiling point. This happens on the "suction" or low pressure side of the system (pump) and with any increase in altitude. This is why electric fuel pumps should be mounted as far from the engine as possible, maintaining pressure all the way to the carburetor. My experience with vapor lock started with flathead V-8's which had to lift the fuel up to the top of the engine (bad, really bad!) Later on Ford caught up and mounted the fuel pump as low as practical, but today with alcohol in the fuel and a combination of things like a small diameter fuel line in close proximity with engine exhaust heat, and even heat reflected up from a hot highway, this is a bigger problem than ever for the old fuel systems. Climbing a mountain pass on a hot day couldn't be a worse set of circumstances.
Ford had a similar problem early on by mounting the water pump on the cylinder head, that centrifugal pump will not pump steam! Big problem, catastrophic - once it boiled you were not going to cool it down using the water pump, and it took them about seven years to move the water pumps down as low as they could ('28-'36) and it was a few more years before they adde a pressure cap to raise the boiling point!
Whoever put the first fuel pump right inside the tank, submerged in the fuel was a genius..
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I do love my electric fuel pump, and my Galaxie really benefited from it.
My truck (76 F100) doesn't seem like it cares as much , most likely from the more open under hood environment. The truck also has a ton more frontal area and subsequently more air flowing through the engine bay.
I've been curious to see how 100% gasoline fares, but honestly with the things I listed above, I just haven't had any more issues, so I quit fussing with it all.
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i drove my comet a few times today.i have more than a vapor lock problem.my fuel level in my sight windows is low so i raised the level,went for a ride ,it died again.i looked in the sight windows and my fuel level was low again.its running itself out of gas now.
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i know they make a plate to cover the fuel pump hole,but can i just leave the man. fuel pump on the motor with the lines unhooked when i switch to a electric fuel pump.or can i run both pumps at the same time,elec. in the back and man. in the front
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You can do both of those things, won't matter. Usually feeding the manual pump with the electric will resolve the vapor lock issues.
Here's one other thing you might look at, and I have personal experience with this one. I would shut my 69 Mach 1 off hot, then five minutes later start it. It would die about a quarter mile down the road, and it was not from fuel starvation, it was from flooding. What I finally figured out was happening was as the car heat soaked after shutoff, the carb and fuel lines got pretty hot. I would start the car, and then the overheated fuel coming out of the fuel line would hit atmospheric pressure when it entered the carb, and it would boil. Modern gasoline has a very low boiling point, around 150 degrees or so. Anyway, when the fuel started boiling in the carb it would spit out of the carb vents and go down the throat of the carb, and flood the engine. Felt just like running out of fuel, but it was too much fuel instead. I finally figured this out one hot day by letting the car run in the driveway with the hood down and the air cleaner off, then shutting it off, and restarting after a couple minutes. When it started to die I lifted the hood and observed all this fuel flooding out of the carb vents and into the carb.
I solved the problem by installing a return style fuel system, so that hot fuel couldn't sit in the lines in the engine compartment. I kept the mechanical pump. I also insulated the lines to keep them from getting too hot.
Any easy way to check for this problem is to put some 110 octane race fuel in the car. It will have a higher boiling point, and keep this from happening.
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thanks everybody, hey Jay,i think i will bypass my man.pump to keep my fuel line away from the heat of the pump.its mounted on the block and near the headers,so i think i will block it off or bypass it just so my fuel wont get as hot.i believe my fuel has boiled in the past but right now im pretty sure im running out of gas because it does it even on a short trip when the engine has not had time to warm up yet
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Sounds like your next step is to Tee in a fuel pressure gauge close to the carb inlet. Tape the gauge to your windshield, drive and monitor what the pressure is actually doing.
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and don't forget to put a wooden clothspin on the fuel line right b4 the carb........... waiting..........waiting..........still waiting..................
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Sounds like your next step is to Tee in a fuel pressure gauge close to the carb inlet. Tape the gauge to your windshield, drive and monitor what the pressure is actually doing.
i need to do something like that ,its driving me crazy trying to figure it out,i think jay might be right after all.i run it a while today,let it set a few minutes and it acted like it was flooded when i tried to start it.i need to go from my gas cap to the carb and figure it out
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Easy test - race gas. If the fuel is boiling and flooding into the carb, you won't see that with some good leaded 110 octane race fuel...
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gas is boiling out of my squirter nozzles when it gets hot.i got it good and hot ,it started acting up,i pulled the breather off and gas was pouring out of the squirter nozzles
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Yep, you are boiling the fuel in the bowl and it escapes from the shooters. Try this one although now its not really necessary. When hot and off, immediately pull the sight plug off the bowl and watch the fuel bubble and pour out. Best to have a rag under the plug's hole before pulling the plug.
When fully cold, fire it back up with the sight plug out to check that the float level is spot on. Bet no fuel comes out or only a dribble IF the float's height is set right.
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i just let i cool for 2 hours ,took off down the road and it died 4 houses down the road,i got it cranked back and brought it back home.im getting afraid to go anywhere in it right now.im having problems getting the fuel level in the sight window on the primaries,its not boiling out in the back just the front.when i loosened the screw to to raise the fuel level all the gas in the front bowl drained down in the carb and out the over flow tube. it didnt have time to heat up this time,thats what gets me.
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Do you have phenolic spacer or anything to restrict heat transfer to the carb?
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i just let i cool for 2 hours ,took off down the road and it died 4 houses down the road,i got it cranked back and brought it back home.im getting afraid to go anywhere in it right now.im having problems getting the fuel level in the sight window on the primaries,its not boiling out in the back just the front.when i loosened the screw to to raise the fuel level all the gas in the front bowl drained down in the carb and out the over flow tube. it didnt have time to heat up this time,thats what gets me.
O.k. now that's different. A stuck or sticky float will do exactly what you said. Time to remove the front bowl and see why the float is sticking. If a brass float, make sure it's not filled or partially filled with fuel as the solder joints have failed. If a black plastic float, see if it does float in a small can of gasoline.
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Do you have phenolic spacer or anything to restrict heat transfer to the carb?
yes 1 inch
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it has plastic floats in it.i took it apart and i didnt see anything going on so i put it back together,thats when i went down the road and it died. i all ready had plans to get a new 850 double pumper,i bought the 950 thats on it now used and im not too happy with it anyway.
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What are you using for a fuel filter and where is it in the system? If your fuel tank was allowed to set for several years with old gas and non use, such as some of these old cars with different owners have subjected them to, can create a really fine sand from corrosion of the old gas. It can be almost impossible to filter and can flow through several inline type filters. What happens then, is the sand is so fine, it gets in the needle and seat and can stick shut or open. Causes flooding one minute and starvation the next.
It is so fine you can't see it, unless there is a bunch, like in the bottom of a sediment bowl type filter. However when you manipulate the needle by hand, like when you open it up to check for problems, you can hear it grind. The only way I have been able to stop this issue is with a sediment bowl type filter, the sand is tiny but heavy and will sink out of the gas and not flow through the filter.
Nick
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it may be sand left from dried gas.the first carb i had on it was a old 850 that ran great.then about a week or two after i got my new motor running that carb went south.i have a inline filter a foot from the carb but it is the regular type.my car set 4 years before i put this engine in.i noticed when i adjusted the float on the front,it did not feel right when i went to tighten it back while holding a wrench on the nut they wanted to turn together and the screw would tighten before the nut under it would like something was interfearing
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ok 110 octane in a clean tank and a new bowl type inline filter.i dont see why that shouldnt fix it.this problem started all at once a few days ago,but it may have taken a while to get some sand in the wrong place.
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i hate to bore you guys but i got a ton of info off you all on this topic.
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We are not bored at all! What's boring, is when nobody posts anything :)
Nick
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how much rubber line , ? , you can insulate your fuel line , do you have an insulating spacer between carb and manifold , how much upper aluminum do you have , and are your filters plastic ? , ethanol eats at plastic and clogs them .... an electric pump helps , you can also run a return line .. small one .... , how close is your fuel line to the block , manifold ... Bud
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how much rubber line , ? , you can insulate your fuel line , do you have an insulating spacer between carb and manifold , how much upper aluminum do you have , and are your filters plastic ? , ethanol eats at plastic and clogs them .... an electric pump helps , you can also run a return line .. small one .... , how close is your fuel line to the block , manifold ... Bud
my lines are rubber under the hood,i have a 1 inch spacer,metal fuel filter,i dont have a return line.i dont know how to do a return line,i have never seen one or how they work.i put 110 in it yesterday,its doing fine now,but im worried the summer heat will effect it
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Do you run rubber from pump to carb under hood ? if so does it contact the engine or manifold any where ? ..
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i dont know how to do a return line,i have never seen one or how they work.i put 110 in it yesterday,its doing fine now,but im worried the summer heat will effect it
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Check out this vid on how-to: https://www.youtube.com/watch?v=YUmaAQoHggM
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Do you have a spacer under your carb. Sometimes that will help keep the carb a little cooler.
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i have a 1 inch spacer
yes 1 inch
Nick
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Hey Bob, thanks for the video link! This thread got me thinking too. Last year I was at a large show and cruise and after 20 minutes of unplanned idling in traffic my cooling system started to lose ground (I have addressed that). Problem was once she got warmer and sat idling she lost all power and then shut down long before an actual overheat. After a 10 minute wait with the hood up I was able to re-fire, get by the issue and then out into traffic as normal. My headers surround the fuel line (Hooker SC's), so even though I routed the line away from them I still have 1 tube that passes beneath the line, figure that fuel was just sitting too long in one place.
Return line next on the list for drivability in all situations, other factors could have caused my problem (as described in this excellent thread), but this is just a smart move in my view-
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Hey, you're welcome. Always glad to help. :)
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i have been driving around for 2 days with no issues.ever since i put the 110 leaded racing fuel in, my car has been doing fine.i watched a few youtube videos,and looked up gas boiling points on the net.i am convinced running cheap winter grade fuels on warm spring days will cause heat soak,gas boiling,vapor locking,etc. im still going to do a few mods to help keep my fuel and engine bay cooler,but the cheap fuel was 90% of my problem. thanks im glad i joined this forum!!
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i have been driving around for 2 days with no issues.ever since i put the 110 leaded racing fuel in, my car has been doing fine.i watched a few youtube videos,and looked up gas boiling points on the net.i am convinced running cheap winter grade fuels on warm spring days will cause heat soak,gas boiling,vapor locking,etc. im still going to do a few mods to help keep my fuel and engine bay cooler,but the cheap fuel was 90% of my problem. thanks im glad i joined this forum!!
Glad it worked out for you. I only had the problem that 1 time, I run corn-free 93 pump gas in my 9.8:1 dish 445. You may even be able to come down from where you are to save cost.
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hey Lenz,i have 10.7 speed pro pistons in my 433,i think im around 11 to 1 actual. i was running half 93 and half 110 before i started having trouble.i had filled it up with 93 a couple times when it went haywire,but i couldnt link it to the bad gas till you guys brought it up,i think Jay brought it up right away,thanks