Fuel Line Vapor Lock?

[HAN8L1965]

Went to go for a drive today, extremely hot in Ohio 85-95. Started car started right up then it started to stutter. Looked at my clear fuel filter at front just before carbs, very little if any gas coming forward. I have a facet fuel pump it is chirping away as usual I also have a filter before the pump. It cleared up after 10 to 15 minutes took a ride around the block fine. Headed down the raod 3 miles later a couple back fires and that was the end. Waited a few got her started got her back home still starving for fuel.

So 4 hours later I go out turn her on and she starts right up look under the hood filter has the regular amoount of fuel flowing let rur for 15 to 20 everything is right.

??? Is this vapor lock? last time car was driven it was quite hot outside and I had driven it about 2 hours in the heat. Brought her home shut her down, graeat drive.

If it is vapor lock what creates this situation? The little woman was not overly excited sitting at the side of the road but as I said to her Its only 3 miles back.

Mark

 

[toysrrus]

Hi Mark,

When I had my "Frogeye"; I had very similar problems. I found that my feul bowls were dry when she started spitting, stuttering & ulimately shut down. Let her sit for about 10min. & off I went. Sometimes a couple of miles; Sometimes all day.

After changing over to an "Elec. Feul Pump"; All problems were solved. I was running off the Orig. Mech pump.

What the heck is a "Facet Feul Pump"?

Russ

 

[SilentUnicorn]

... but as I said to her Its only 3 miles back.

Mark

that is not too far for Her to push....



m

 

[HAN8L1965]

Facet fuel pump is the little square box electronic fuel pump that a lot of us use. so the pump is not in question as I could hear it operating. I was prepared to replace the filter before the pump but as mentioned it is now running perfectly. My tank is clean and totally restored and enameled. I am wonderingI have been using a no lead additive to my gas, is this possibly gumming up the works?

Mark

 

[HAN8L1965]

Under the search topic there is an explanation of what creates vapor lock but the one solution seems to be an electronic fuel pump which I already have. This all may have been a fluke but would prefer it not to happen again. My fuel line is stainless. Lines running from tank to pump are original steel which is clean and new rubber. It sounds like possibly the fuel in the main line vaporized after my last trip and pushed the fuel back past the pump which needed to replenish the fuel before working properly. Needed to burp, does any of this make sense?

Mark

 

[Guest]

How old is the fuel, when is the last time you ran it?

The good thing is you have an electric pump ~AND~ an assistant in the car. This happens to me from time to time when the fuel gets low and it's hot out. I have the spring loaded fuel line clamp at the carb. When this happens, I leave the key on, jump out and pull the line off the carb and cover it with my thumb, I burp the line till fuel come to the end, cover with the thumb again and stick it back on the carb.

Since she is with you, she can shut the key off when you tell her and put the line back on. It only takes a few seconds and she will be proud of her McGyver husband who kept her from waiting on the side of the road. Point the line AWAY from the engine when you do this.

Next time it happens, give her a wink and tell her, "this'll take just a second" and jump to it.

Sometimes I have to give a quick suck on the line to get fuel up to the pump, as mine is under the hood.

Check to see if your line go close to heater hoses or the exhast manifold or pipe. Insulate where nessisary.

No biggie, just takes a second.

If you feel it stutter while driving, bak off the fuel and let it idle with the cliutch in. Usually it will purge itself quickly. I would have already gone back to a mechanical pump if it wasn't for this trick.


Sometimes blowing backwards throught the line will wet the pump enough to prime it. try that first, but be very careful either way.

 

[HAN8L1965]

Thank you Kellysguy for your solution and wisdom I was hoping there would be a little more abuse in getting to the answer but just the same you are keeping my wife off the street.
Happy motoring,

Mark

 

[dklawson]

The square Facet's have a plunger in them that oscillates back and forth to move the fuel. If you mounted the pump horizontal, the plunger can wear away a bit of the pump internals creating enough clearance that fuel delivery and pressure can suffer. If you still have your installation instructions you'll note that Facet wants those pumps mounted at about a 45 degree angle, lower than the tank, and hopefully not in the engine compartment. The angle slows the wear, mounting the pump lower than the tank allows it to work as a pusher vs a puller, and there is simply less heat away from the engine. I've had two Facets wear out after years of service. In both cases I could hear the pump ticking away but no fuel was being moved in either of them.

 

[JPSmit]

In both cases I could hear the pump ticking away but no fuel was being moved in either of them.

+1 I have a mechanical pump and know nothing of these new fangled electric pumps, but, doesn't sound like vapour lock - sounds like fuel starvation.

Rule #1 of LBC's never assume - don't ask me how I know.

 

[regularman]

If the fuel boils in the line, then the vapor makes its way back down the line and eventually can get into the pump and the pump lose its prime. Has the gas been in there since the winter? Winter gas has a different quality than summer gas and can boil quicker. I feel for you, its a pain solving these things some times.

 

[Guest]

Check to see if your line go close to heater hoses or the exhast manifold or pipe. Insulate where nessisary.

I also noticed I had to insulate my fuel filter and that helped out too. I had this problem a good bit. It get's really HOT down here. It might take you a trip or two till you get it isolated. I think the main problem with mine was I had the thin gasket under my DGV which led to boiling. I changed it out and it was much better, but still does it from time to time, so be ready. My next move is to fab a heat shield to go under the carb.

Also, try not to use ethanol if you can. I noticed it was worse with that.

I believe the problem is mainly in the quality of fuel today. I've noticed it's not nearly like the stuff we got years ago. So few cars are carbed today, manufactures don't need to worry about this problem and cut back on fuel quality to save money. My car NEVER did this before, and it has new EVERYTHING on it, so it's ot a parts issue.

My point is, even if you fix what it's doing now, it still might not be "fixed". Don't be suprised if and when it happens again. Mine only does it now after I leave wal mart and I'm low on fuel(1/4 tank). When I go around the long sharp turn to get on the highway, the car sputters and spits after I've made it through the turn. Sometimes I have to pull over and burp it. I attribute this to two things.

A.) low fuel level in a non line-baffled tank. It was never designed to hold fuel around the pick up continously like a modern injected tank is.

B.) The fuel in the float bowl has boiled off while I was in the store, thus creating a lower fuel level in the bowl. I have just enough fuel to make it around the turn, but the pump can't resupply cause the pickup is sucking air.


No matter what I do, there is no way for me to be able to raise the boiling temp of the fuel that is suffereing heat soak-back in the bowl when it's not running.

Modern cars don't have this problem, due to the higher inline fuel pressure needed for injection, so the problem isn't addressed at the refining level anymore (IMO).


Before I put the thick gasket back under the carb, it would do it going over an overpass. This gasket was designed 35 years ago, and they never had this problem with it then. There is no reason why I shouldn'e be able to use this gasket, other than fuel quality, and there is nothing we can do about that, other than go to injection.

So we might be able to make the problem better, but I'm unsure if we'll ever be able to get it to go away permantly.

 

[bigjones]

I've been gone awhile - problems with the air conditioned car. If you think diagnosing MGs is bad, try a Toyota. I still have not figured it out but setting the idle speed involves replacing a $200 gizmo, the coil is in the distributor and the fuel pump is in the gas tank.

Anyways, just to let you know I'm in the same boat/ MG Midget.

I've wrapped all the fuel lines with insulation pipe, tried to get more fresh air into the engine bay, made a heat shield, insulated the fuel bowl, said three Hail Mary's, all to no avail. If I figure something out I'll let you.

Next on the list is mounting a 12v cooling fan from a PC on the fender or somewhere and pointing it at the carb bowl. Or is that crazy?

Cheers!