• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Vapor Lock, Out of Gas, Hmm, Ahh, Don't know?

Share this page

vette

vette

Darth Vader
Silver
Country flag
Offline
The Healey engine died at speed, twice. Although not offend. Once last summer and again just yesterday. Both times it turned out to be lack of fuel. i've been driving it alot, before, after and since with no troubles. I have two fuel pumps and they are controlled by two switches. These switches as Double Pole - Double Throw toggle switches. the reason I designed it this way is that I use the normally open contacts of each switch as an electrical interlock to keep the pumps from coming on at the same time. When one switch is on it opens the circuit to the other pump. that way each pump is intended as a back up, not as a volume enhancer. So anyway, this lack of fuel situation has at each time occurred just a few miles after a start up and comencing travel on the road. Each time it was about 2 miles after start up. Which I figure would be about the time it takes to drain the fuel bowls. I know that it is fuel starvation by a couple of charactoristics.
One is that the engine doesn't just die immediately, it just starts to slow down and then a fluttering gas pedal then it is dead. both times it happened that way. Usually when it is electrical, the engine would just quit , flat out stop dead , quickly. But this is a slow loss of speed and power over just a approx 30 seconds then no engine running.
So yesterday when it happened, I had just pulled out from a "Petro" station with a full tank of gasoline. I was motoring along a 2 lane road at constant speed of about 45 mph, just moments before i had slid it into 4th gear. I was about 2 miles away from the "Petro" station and all of a sudden, started loosing power. Tried to keep the revs up, pumped the gas, engine fluttered, then stopped. Luckily I coasted into a near driveway. Cranked engine, no start. Then I noticed the silence, no fuel pumps ticking. I flipped to 2nd pump, and still no ticking. Flipped toggle switches back and forth between pumps and still no ticking. Looked at voltage gauge, had good voltage and engine cranked normally. Thought, well I'd better check for spark. Let ignition switch on while going around to open bonnet and look over things, just popped straps on the distributor cap and ALL OF A SUDDEN i HEARD A FUEL PUMP TICKING. it was a good tick, constant for a period of time normally associated with the carb bowls filling up. Hmmm, weird now. Put the straps back down on the distributor cap, jumped into the driver's seat, hit the starter and it fired right up. Drove it home with no more trauma. So why did it run out of fuel at constant speed, with full tank of gas? Why did the pump just start pumping all of a sudden, even when I toggled between pumps just minutes before? I checked electrical connection, I had good voltage. And it only did this one other time a complete year earlier. Hmmmm? Any ideas? Thanks, Dave.
 
So why did it run out of fuel at constant speed, with full tank of gas? Why did the pump just start pumping all of a sudden,

CUZ: it's a Healey and they just love attention.---:angel2:
 
Couple questions: are the pumps points or electronic, and why didn't you switch pumps as soon as you started losing power? If both pumps are points-activated, and you ran on one pump continually, the points on the second pump might have oxidized whilst dormant. When you stopped, switched pumps, and futzed with the ignition you might have jiggled the car just enough to get the second pump going. If I had a dual pump setup, I would switch pumps regularly to assure both pumps work, and to 'exercise' both pumps. Besides points oxidation, the diaphragm can stiffen if not used regularly.

I've experienced a sort of 'vapor lock' on my BJ8 since I've been using 10% ethanol fuel--not by choice--but it usually just causes some stumbling after starting when the engine is heat-soaked, and stops after the coolant temp drops to the normal running range.
 
Even though its a Healey, I built it with mostly Chinese parts. :smile: I do rotate the use of the pumps. Whichever pump it was running on when i last used the car I then use the other pump the next time around. As a matter of fact when I get in the car after a few idle days, I usually go back and forth between pumps before I start it to make sure each pump is "charged up to pressure" . One pump is points the other electronic.
The vapor lock after heat soak might be a viable idea, we certainly have the ethanol here and on this day I was running hard for about an hour and stopped for fuel on my way home. Although I don't think that was the case a year ago. When it happened last year, I did almost immediately switch between pumps (when this happens you aren't sure what is going on at the time so switching pumps doesn't immediately come to mind) yet it did not keep it from shutting off. I believe that the vapor lock is occurring after the pumps and closer to the engine or carbs in that running the other pump doesn't clear it because the pumps are both still seeing pressure and are fully charged. A moment off the road and maybe rocking the car around maybe what is clearing the vapor lock then the pump can pump fuel to the bowls again. In any event I certainly don't want it to happen again but if it does I will try to have better presents of mind to recognized some signs. Thanks for the responses. Dave.
 
Are both pumps fed from the same electrical circuit? Yes, when you tested it after it started working again the electrical supply worked properly. But you still could have an intermittent electrical issue that cuts off both pumps.
 
blueskies said:
Are both pumps fed from the same electrical circuit? Yes, when you tested it after it started working again the electrical supply worked properly. But you still could have an intermittent electrical issue that cuts off both pumps.
Click to expand...

That's my thought. Make sure your connections are good at the supply to the switch, at the fuse box, post 3, and coil.
 
Has the inside of the fuel tank been coated (I apologize if I overlooked that in your post, but really long paragraphs seem to give me symptoms of vertigo ;) )?

It is well known that pieces of the coating, and/or plates of oxidized steel, can float over and get sucked up to the tank's pickup tube, then fall away when the suction is lost. Makes for some real fun troubleshooting, especially at night, when repeatedly be stranded along dark stretches of Louisiana highways!
 
Vapour lock tends to occur when you have stopped for a while with the engine running or are driving slowly, for instance in traffic. it does not usually occur when driving normally. Don't rule out a faulty coil.
 
I had a similar problem, i thought was associated with vapor lock. Then one day car quit after only 5 min of driving. Fuel pump was silent, no amount of hitting it would make it run. All of a sudden the pump began to start ticking, the engine started and I made it home. I found the little screens in the carbs clogged with little bits of black material.( under the banjo ). I suspect the fuel pump was disintegrating from ethanol fuel. I replaced the pump with an ECCO pump, no further problems.
 
blueskies:
"Are both pumps fed from the same electrical circuit? Yes, when you tested it after it started working again the electrical supply worked properly. But you still could have an intermittent electrical issue that cuts off both pumps."
Power is fed from the same dedicated fuse, I have modern style 'U' shaped fuses in modern fuse box. But your right I need to check all the connections.

Randy Forbes:
" Has the inside of the fuel tank been coated:"
Yep inside of tank has been coated and I didn't think of that. Will try to check if things are floating around.

DerekJ:
 " Don't rule out a faulty coil."
Could be a Coil, maybe I'll change it, but waiting another year for it to do it again will be frustrating.

BlueHealey1951:
"I suspect the fuel pump was disintegrating from ethanol fuel."
That dang ethanol, I'm moving to California then I'll know for sure how crappy my gas is.

thanks for all the ideas. Dave.












 
Regarding ethanol, one way to avoid that is to buy premium gas; that is ethanol free, at least here in western Canada. I buy that for classic cars and other motors that don't get run a lot.
 
Regarding ethanol, one way to avoid that is to buy premium gas; that is ethanol free,

OH SURE !!-----:highly_amused:
 
steveg said:
I wish it were that way here in S Cal.
Click to expand...

Steve!- Me TOO But:.
wink-new.png
-

Some 76 stations have 98 Octane leaded fuel in special on site tanks. it is not at the pumps. Last time i checked it was $5.00/Gal

I always added 5 Gal when I hit the road on a long trip, some times I would find it on my way TOO

Aviation gas at private airports can also get you 110 octane leaded fuel.
 
So as to provide closure for a future enthusiast that stumbles on this thread via a search, will Vette confirm that the issue causing fuel starvation was an aftermarket fuel tank sealer peeling away from the inside of the tank?

So to resolve the issue, a new tank was installed...
 
As I was discussing in my other related thread about searching for a source for a good gas tank, I did buy another tank from Moss. I did some internet searches and it seemed that, State Side, Moss was one of the good sources that was also recommended by a few others. I am confident that the tank was the offending piece in this saga. When I separated the joint of my fuel line to the inlet of my first fuel pump I found a couple of pieces of scrolled up plastic stuck in the banjo. When I looked down into the hole of the tank after removing the sending unit, a good portion of the bottom of the tank showed that the white, plastic (teflon maybe) coating was peeling loose from the metal. I don't know what else that stuff at the banjo could have been but the deteriorating coating. Even if it was something else that might have inadvertently been sloshing around in the tank, the evidence of peeling on the inside of the tank proved to me that the tank could not be trusted. After installation of the new tank I went for about a 20 mile run with no issues.
The Moss tank seems to be a good match. It is painted well on the outside, the tank outlet union matches the exact location where the old one was so that your outlet pipe to fuel pump line will thread right to it without any fussing. The new tank has at least 3 baffles in it which will help to stabilise any fuel sloshing, I think the old tank only had one, maybe two. So it was an easy switch out and seems to work well.
 
pure gas app for the smartphone will find non-ethanol gas, usually not hard to find in farm communities. What coating was put in Your tank? eastwood, tank renu? might help to know which to avoid.
 
I would also like to know which product was used, and if the failure was thought to be the product itself, or due to alcohol or other additives attacking it. 20+ years ago, I used whatever Moss sold on my brother's Alpine, and he never had any trouble. AFAIK, he always ran premium gas, w/o alcohol or MBTE. The car has been gone for several years, so I have no idea what's happened since alcohol has become more common.

I'm facing a similar job, so maybe I'll call Eastwood, and see what they say about their product. Thanks for the reference to pure gas app. Jim
 
Last edited:
Can't say what coating was on Vette's tank but I just replaced my BT7 tank that had same sort of problem. After I let it dry out well I looked into the sender unit hole and saw bubbles of soft material coating the tank. There were strands attached to the coating as well that probably waved when the tank was full. The bubbling up may have been because the stuff(still soft to the touch) never adhered correctly or fully. PO told me he had coated the tank but at the time I did not ask what was used It was a greyish color and when looking down the fill tube looks to have been pored in there.
 
IIRC (now, I think closer to 30 years ago!), the Moss product came in a qt can, and was a "whitish" color-maybe light grey(?). We poured it in through the sender hole, and then turned and rotated the tank every few minutes to coat all sides. We had carefully cleaned the inside of the tank, and I think I dumped in a couple of qts of isopropyl alcohol and then shook/rotated the tank to help evaporate any left over water. It probably then sat a week before coating.

I wouldn't say the coating dried hard, but I don't remember it being rubbery either. No strands that I recall from what I could see with a flashlight and mirror through the sender hole. It did successfully fix a few weeping pinholes. Jim
 
Back
Top