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Discussion Topic:
Fuel problem
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joe b |
06-09-2013 @ 9:50 AM
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Member
Posts: 389
Joined: Oct 2010
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I have had a continuing fuel problem with my '41 that started this spring. When I went to start it, it would not start. Found no fuel getting to the engine despite having an electric fuel pump. Found that Ethanol had eaten up a fuel filter I had plus the flex hose between the firewall fuel line and the mechanical fuel pump was eaten up and crumbled in my hand when I took it off.Took the electric pump apart and found it to be clean. Bench tested it and it worked fine. Replaced the flex line with an Ethanol proof one. Car went fine. Went on a tour and drove 53 miles,stopped to eat and came out and car ran fine. Drove another 47 miles to destination. After the event,came out after 4 hours and went to leave. Car started right up went 3 car lengths and stopped. No gas to carb. Engine temp 150 degrees. Checked and had good spark. Would light starting fluid but still no gas.Became a Flathead on a flatbed. Next morning after having sat for 13 hours it fired right up and ran OK. So.... I replaced the entire fuel line from tank to engine,installed a new mechanical fuel pump and electric fuel pump,rebuilt the carb.installed a Skip Haney rebuilt coil and new condensor,removed the sending unit from the tank and found that tank was clean (it was installed new 7 years ago),drained the gas and it was fine,removed gas line from tank and rodded the pick up tube and it was clean,blew air through it both ways and the air stream was good and strong. Checked new electric fuel pump and found it was running backwards, reversed the wiring and it ran correctly. Filled the gas tank,ran the electric pump for 10 seconds,hit the starter and it fired right up. Went to go to a car show yesterday and went 2 miles in the city and...ran out of gas with another tow home. I am at the end of mu rope and out of ideas.
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supereal |
06-09-2013 @ 2:45 PM
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Senior
Posts: 6819
Joined: Oct 2009
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Have you checked the gas cap to be sure it is properly vented? When the tank is partially filled, there is usually enough air to allow adequate fuel, but when the tank is at or near full, it doesn't take much time to starve the flow. The last time I chased that kind of problem, I found a radiator cap on the gas tank! If it happens again, uncap the tank to see if it cures the problem.
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joe b |
06-09-2013 @ 3:26 PM
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Member
Posts: 389
Joined: Oct 2010
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Super, I have tried that and it seemed to make no difference. The cap is the same one that has been on the car since I bought it 16 years ago. Old.
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blarge |
06-09-2013 @ 7:11 PM
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Member
Posts: 94
Joined: Oct 2009
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Joe B: To track down the root cause of your engine stopping due to a lack of fuel will require you to gather more info that will lead to an analysis to determine what is wrong. Your work so far indicates to me that a set of pressure readings is needed. I would make a temporary new fuel line from the fuel pump to the carburetor that has a tee in it to allow the pressure into the carb to be observed. Be careful, as any fuel leaks can start a fire! Run a line from the tee to a pressure gauge that can detect 0 to 5 psi and temporally mount the gauge where you can see it as you are driving. If the engine stalls and there is 3/5 psi pressure on the gauge, the float in the carb is stuck closed and the pressure will drop down if you tap in the carb inlet to free up the float needle. If the engine quits and the pressure to the carb is zero, you need make a temporary flex line with a tee in the fuel line going into the fuel pump to measure the vacuum of the mechanical pump, or the pressure of the electric pump when it is running. Most diagnostic vacuum gauges also have a pressure reading scale too. Mount this gauge where it can be seen while driving too. With the electric pump switched off, a 6 to 10 inch of Mercury reading while cranking or running on starting fluid, but no fuel going to the carb causing a pressure reading of 2 to 5 psi indicates a restriction somewhere in the delivery side of the fuel system( line,electric pump hoses collapsing, junk floating around inside the tank, etc.). With the electric pump switched on and the engine not running or cranking, the fuel pump inlet and carburetor fuel line should see 3 to 5 psi. If no pressure on either gauge, there is a restriction before the electric pump( rubber lines or in the tank), or the pump itself is not pushing fuel forward. If pressure is at the gauge on the fuel inlet hose only and not the gauge on the carburetor fuel line, the mechanical pump has a blockage. Joe, I know this recommendation is a lot of work, but reading like these will provide clues as to what is not working when the engine quits. The ethanol in our fuel supply is an evil thing to our old cars. Bill Large 586-677-4790 Detroit
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supereal |
06-09-2013 @ 7:43 PM
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Senior
Posts: 6819
Joined: Oct 2009
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In addition to Bill's suggestion, if you have the spring type hose clamps anywhere between the tank and the carb, replace them with the worm gear type. The spring type, usually supplied with an electric pump, tend to leak air. This allows the pump(s) to lose prime and imitate running out of gas. If your problem happens with both pumps, I'd réclamp them. We don't use the hoses in the kits because they are often not fuel proof. If you are not using hose barb fittings between steel and rubber connections, that is also a problem.
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joe b |
06-10-2013 @ 4:33 PM
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Member
Posts: 389
Joined: Oct 2010
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Super, Thanks for the suggestion. I used spring clips and hose supplied. Looked under today and found gas moisture at both ends. Removed hose supplied and replaced with Ethanol proof hose and worm gear clamps. Whodathunkit?
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supereal |
06-10-2013 @ 7:20 PM
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Senior
Posts: 6819
Joined: Oct 2009
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Me. I've found that out the hard way!
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TomO |
06-11-2013 @ 7:03 AM
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Senior
Posts: 7256
Joined: Oct 2009
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I agree with Bill Large, do some diagnostic work to isolate the problem.
Tom
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joe b |
06-14-2013 @ 12:00 PM
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Member
Posts: 389
Joined: Oct 2010
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I think I may have found my problem. After all of the items I have posted above,I let the engine run with the throttle pulled out at fair high RPM and it ran fine. The electric fuel pump was not on. Pulled back in the garage account rain and it sat 5 days. Got in,fired right up and went for a drive. I got 7 blocks before it quit. Turned the electric fuel pump on and started again. Drove about 53 miles in city,on Interstate at 65 MPH and up hills in high gear and it ran fine. So...it appears that the fuel pump has to be on all the time. The fuel pump is a Carter EFP9350-6C. I called C&G Tech line and they said the pump is a flow through and I can use it for priming and backup. I called the Carter Tech line and they said the same thing. But this is not the case with my installation. A few questions/concerns: If I am in slow traffic or a long idle situation will the electric pump overflow the mechanical pump or carb? Is there a way to have the electric disabled in case of a bad accident? I am a retired fireman and this bothers me. During the drive I did not smell gas and after I stopped found no evidence of overflowing.
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TomO |
06-15-2013 @ 9:50 AM
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Senior
Posts: 7256
Joined: Oct 2009
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Joe, You said that you replaced the fuel line going to the electric pump, could it be collapsing under the vacuum from the mechanical fuel pump? Your mechanical fuel pump should be able to deliver fuel through the pump. The best way to wire the electric pump is through an oil pressure safety switch.
Tom
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