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Electric fuel pump trouble

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Old 09-22-2015, 02:40 PM
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LiquidDrink
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Default Electric fuel pump trouble

I recently aquire a 1969 mustang 5.8L 351w with a holley 750cfm carb. I don't know exactly what cams it has, though they are definitely not stock. I think the electric fuel pump is pushing too much fuel. The floats are adjusted down but i still get a strong fuel smell. The holley manual I have calls for 5-7 psi. I'd like to install a mechanical pump but I'm not sure if the race cams would affect it in any way. If so, would it be better to get a smaller electric pump or add a pressure regulator to the line?
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Old 09-22-2015, 02:55 PM
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69mach1377
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Are you needle and seat sealing? If the car sat for a while, they could be gunked up. Pull and inspect them.
Do you have a pressure gage before the carb?
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Old 09-22-2015, 03:51 PM
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jwog666
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the stock cam driven pump puts out less volume than the electric pump does. you need to install a fuel pressure regulator on the supply line, and i suggest running a return line as well, its easier on the pump and prevents overheating and boil off of the fuel. something like this should do http://www.summitracing.com/parts/qf...FYNFaQodrosMkA
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Old 09-22-2015, 08:11 PM
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Originally Posted by 69mach1377 View Post
Are you needle and seat sealing? If the car sat for a while, they could be gunked up. Pull and inspect them.
Do you have a pressure gage before the carb?
I cleaned and rebuilt the carb with a holley kit and replaced the needle and seat so I don't think that's the problem. I don't have a pressure guage though
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Old 09-22-2015, 08:14 PM
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Originally Posted by jwog666 View Post
the stock cam driven pump puts out less volume than the electric pump does. you need to install a fuel pressure regulator on the supply line, and i suggest running a return line as well, its easier on the pump and prevents overheating and boil off of the fuel. something like this should do http://www.summitracing.com/parts/qf...FYNFaQodrosMkA
If I put on on the line in between the pump and carb, shouldn't that be enough? I thought the pressure regulator has a line that goes back to the tank to relieve pressure so it doesn't mess with the pump
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Old 09-22-2015, 10:37 PM
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jwog666
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pump draws from the tank, then to the regulator, pressure is sent at your chosen setting to the carb, and the unneeded fuel is dumped back to the tank


kinda like this
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Old 09-22-2015, 11:40 PM
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That looks nice, I like that setup
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Old 09-23-2015, 09:09 AM
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racer_dave
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or run a good mechanical pump. I run a Carter on my racecars with a holley regulator in line. no problems ever, steady pressure. Feeding 368ci @ 8000rpm, never starves for fuel.
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Old 09-29-2015, 10:06 AM
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mjr46
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no need to run a return line for a carbed set up so mild.......I run a holley blue with regulator set to 6.5 psi........make sure your need and seat are operational.........often the ethanol fuels deteriorate the rubber tip on the seat......now that is to say you have fuel pushing past the seat.......I've run my set up on a 347 with no return for 15 years and the pump is still going strong. Also when and where are you getting a strong fuel smell from?? you will always smell some fuel around the carb area depending on what type of vent system you have on the carb.........are you experiencing any running/drivibility issue??

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