Background: 1930 Ford coupe AV8. 59 flatty. Previously running just fine. 2 Holley 59's, stock mechanical pump. New, metal inline 5/16" fuel filter by tank plumbed before auxillary electric fuel pump that I added (see below). For the last year I've been having fuel delivery issues. I have a gauge plumbed into the fuel lines at the carbs. Car has been just been randomly dying on me when cruising. Sometimes after a few minutes, sometimes after a 1/2 hour or more, sometimes not at all. Each time it dies, the fuel pressure has been at zero when it happens. Wait a few minutes and car would start and off we go. Thought it was vapor lock so installed an auxillary electric fuel pump back at the tank in the trunk. Seemed to cure the problem. Took it out for several long rides and the instant I got any stumble (which was the usual symptom before dying), I would flip the switch for the electric pump and car evened out and kept cruising fine. Yesterday I took it out for a spin and 10 minutes down the road I hear the electric pump behind me banging extra loud. A minute or so later car stumbles and dies. Zero fuel pressure. Try to start it several times and the electric pump is banging loudly like it's got no fuel running through it. After about ten minutes I try again and electric pump is loud but gets quieter quickly (I think, "must be pumping fuel"). Starts up and I head home. Shortly, pump begins banging again and car stalls out. Car starts gain after a few minutes. As I turn into my neighborhood the pump gets loud again. I make it into my garage with the pump loud. Set the e-brake and get out. Fuel pressure zero with car still running and electric pump loud like it's not pumping fuel. Shortly the engine dies from no fuel to carbs. Right now what I'm thinking is somehow fuel is blocked from the tank to the electric fuel pump by the tank (Tanks, Inc. universal tank). Maybe somehow there's a piece of debris in the tanks getting sucked into the pickup tube blocking the fuel??? Maybe it becomes dislodged after a few minutes and allows fuel to flow again??? I don't know. It's driving me F-ing crazy. Kind of hard to see inside the tank where the pickup is but I don't see any debris in there at all. I'm going to blow some air back into the tank this morning to see what happens. Any ideas guys? Andy
Tank is vented. Actually removed the cap to check if maybe vent was not working when this has happened in the past and again yesterday and didn't help. Andy
What tank are you using? I had a baffle break inside a custom tank. When I took a corner it would slide over the fuel outlet and block it.
^^^I thought maybe that also. Yes, rubber line from tank to filter and filter to pump. Short runs. All new. Visually checked it for collapsing yesterday. Appeared fine. This is a low pressure set up. Pump is rated at 1-4 lbs. Carbs run at 1 1/2 lbs. pressure so not likely the pump is collapsing the rubber. Just sayin'... Andy
That is the way my Hudson ran, sometimes many miles, or just blocks. I thought it was vapor lock. Real reason was blockage in tank. I would check to see if you have junk in the tank or a pickup issue of some type.
There has to be debris in the tank, I would remove the tank and clean it out. Are you using any kind of stainer on the end of the fuel line? If not, this is one option, it slips over the fuel line and is hose clamped in place. My sure it rests on the bottom of the tank.
Where is the fuel tank mounted? Is it cosiderably lower than where the fuel pumps are mounted? Are the rubber sections of the fuel lines rated for usage with alcohol blended gasoline? Does the level of fuel in the tank have any effect on the problem?
Gents, I may have figured it out. Tank is crystal clean. Went out shortly after posting this morning with intent on blowing some air into the pickup to clear any suspected blockage. Took a good hard looky-look at the fittings on the top of tank at the pickup. "Hmmmmm", I says to me-self. "Those fittings look like they don't have any thread sealant on them at all". Now, mind you...all the fittings came with the tank as I bought it slightly used from a fellow Hamb-er. Never even thought of checking them. When I got it I thought, "Perfect. All the fittings I need to run this tank are already on it." So...I took apart the fittings and no thread sealant on a single one of the four fittings. Cleaned it all up, applied Permatex thread sealant "with Teflon" and put it all back together. Blew some air into tank just for shits and giggles (no floating debris seen in tank after that) and took it for a 90 minute flawless ride in 90 degree weather. Apparently (and hopefully) the non-sealed fittings were allowing air into the line which may be why the pump near the tank was banging like it was sucking air...because it probably WAS. No banging from the pump at all, just the steady "click-click-click" you would expect. Andy
Well, that wasn't the fix for the issue...dammit! Took it for another ride yesterday and after about 45 minutes I hear the electric pump behind me starting to get loud again. I quick pull over before the inevitable stall happens and check the fuel pressure while engine is still running. Zero pressure. I shut it down and wait a few minutes. Starts up again easily with the pump quiet and off I go towards home. 45 minute drive and I get there with no problem. Looks like I'm draining and pulling the tank because there's probably something floating around in there that's blocking the pickup intermittently. I'll keep y'all posted. Andy
May as well redo that rubber line while it's apart as mentioned above. I've had that happen to me, collapsed interior of a line....
You haven't mentioned a fuel pressure regulator. I had a Holley Regulator on a roadster with two 94's, and it would starve itself' and die. Strombergs are a challenge because of the low pressure they run on. I finally put a second inlet on the tank, and installed a regulator in line to that location. Any fuel pressure over 1 1/2 psi went back to the tank. My problems were over..
Have you checked what makes the pump sound like that? Pinch the suction hose near the pump and see how it sounds when the supply is blocked off completely, then loosen a connection and see how it sounds when it sucks air. I suspect there's a difference (and that it may be sucking air somewhere, for some reason).
Could the electric fuel pump be failing? What type of pump is it? Does it feel hot to the touch after running long enough to get noisy. Is the pump mounted close to, or below the level of the pick-up tube in the tank? Can you check the current draw of the pump or has it ever blown a fuse? Is the pump well grounded? Some pumps were mounted with rubber insulators to reduce noise and vibration.
Rubber is new. I'll check that but the pump sounds just like when I tested it dry when installing it. New pump. It's auxillary. Also still running the stock mechanical pump. New filter. I'm away for a few days. I'll get back into it when I get back home. Andy
It wouldn't be the first defective filter , from the description of your system it is the only thing between the pump and the pick up . Worth a look .
First, you say rubber lines are new. Are they fuel line? Just checking, as someone mentioned they could be collapsing. What type of electric pump are you running and where is it mounted? Most electric fuel pumps are gravity feed. If the pump is mounted higher than the fuel level of the gas in the tank-expect problems like this. Is there a fuel filter anywhere between the electric pump and the mechanical? If the electric pump is not working, this will only act as another restriction. I just dealt with this same issue on my ‘63, as when I bought it the previous owner installed a electric pusher pump back by the tank. Problem is it was a gravity feed pump, and mounted higher than the fuel tank. If the pump is higher than the fuel level, you need an electric pump rated to give that amount of lift.
What size is your fuel line from gas tank to the carburetor? How old is the fuel line? I had a similar problem and after several experiences of sitting on the side of the road I found this problem. Ethanal gas can deteriorate conventional fuel lines and it doesn't take long for the inside of the line to get soft and spongy causing it to collapse and starve the gas flow. I only use fuel line designed for diesel engines, it is impervious to ethanal. HRP
I had a fuel starvation issue for several years, it would happen every few hundred miles, but not predictably. When I disconnected the rubber hose upstream of the fuel pump there was a big hiss as air was sucked in, which meant that the pump was trying to suck fuel but creating a vacuum. I had the tank out, made a custom in tank filter screen but finally found the problem last summer when I again had the tank out and blew through the line. This came out of the line: What was happening was that this piece of junk was getting caught in the first bend in the 5/16" fuel line, and gradually rust and dirt from the tank would pack around it, plugging the line solid. When this happened, I would blow through the line by mouth (later I kept a bicycle pump in the truck), dislodging the plug from the bend, and the truck would run great until it migrated back up to the elbow and plugged the line again. I don't know how it got in there, there was a very fine "sock" around the pickup.
I'm suspecting I will find something similar when I pull the tank next week. It's an older "Tanks, Inc." tank so the fuel pickup is a welded bung in the top of the tank. I have not closely inspected it enough to determine if the pickup tube is actually removable from the bung but the people at "Tanks" say it is not. The new tanks have a flange welded into the top of the tank with a plate mounted pickup and vent assembly that mounts to that. Easier to pull it and inspect the pickup. Just ordered new filler tube and sender gaskets. If I pull the fill tube it may be possible to visualize the pickup through that opening. Also, remember that this problem only began last year after over five years of driving it without this problem at all. Andy
I agree. This is an occam's razor scenario. It ain't getting gas, and when you find the why, I'm guessing it won't be complicated...... Good luck!
You may have had a mud dauber leave a nest in one of the pipes while the tank was sitting around and that is what is floating in the tank and periodically blocking the fuel. If you're running an engine fuel pump plus an electric pump and still getting starvation then the problem is between the electric pump and tank. I learnt years ago (embarrassingly) to put a smear of lubricant on pipe fittings before pushing hoses on. I got a bit enthusiastic with one and shredded the hose inner which then periodically blocked the fuel supply. It took a breakdown in peak hour traffic to find it, hence the embarrassment.
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