Before I fired my fresh 401 Nailhead I had to temporary install a Holley electric pump at the tank to prime the system. Once I did that, the new electric pump I installed about 4 feet from the tank worked fine. I also have a new stock mechanical pump at the engine but the inline electric is just for backup. After setting a couple days I have to turn the electric pump on to prime the system to get it to fire. I drove it around the block yesterday for the first time with no problems and drove it on my lift with no problems today. This evening I was going to put my pickup back in the garage and it started but would starve for gas with both pumps running. I had to let the electric run for a bit to get it to move 5 feet. The electric pump is not sounding right but the mechanical should do the job alone. I have set up several cars this way with no problems but this thing is driving me crazy. Do I have two bad new pumps or maybe sucking air some where. Yes the tank is full of gas. Any thoughts?
i noticed that some electric pumps won't let fuel pass through them unless they are running. try taking it out and see if the mechanical will work by itself.
I thought about by-passing it to see if that works. I never have run one of these little units until I installed one on my coupe and it does fine there on it's own. They just seem too small to last but I hate the noise of the Holley.
The tank is a Tanks poly tank vented through a safety roll over valve. I also have the stock vent that comes with the 40 fill tube. Should be plenty of volume there.
I'm never one to run both types of pumps on the same car. Just doesn't make much sense to me. I currently use Carter P4600HP on three cars and never have had an issue. My Dodge Cummins puked the lift pump when the truck was new and I put an old Carter P4070 i had sitting around for 20 years in place of the OEM unit. That truck has 165K on it now.
Always have here. Over kill, maybe! When I had a flathead in my 40 coupe I ran one as my major and another for backup if I had vapor lock problems. Believe me I used it several times to limp home pulling a tent trailer. As long as they are a flow through type, no problem. Now that we have this ethanol problem, even more reason to have a backup. Never liked crawling under a car along the freeway to replace a pump. Much easier to flip a switch and safer to. Just my take!
Me too. I had just the mechanical but always had to the prime the carb after a week or two of sitting. Put small electric at tank with toggle switch. Now I prime with the toggle for a few seconds before starting, off I go on the mechanical only. Works great.
Same here---stock mechanical and electric at tank for priming after it sits a long time-overkill maybe but it works fine
Here is how I do it ............out of the fuel tank to a T ..... one side goes directly to the mechanical pump ........... the other side immediately to your electric pump ............ then a SEPARATE line from the electric pump to a T between the mechanical pump and the carb. Two complete separate fuel supply systems that ca be used to prime or run the car ..... don't forget inline fuel filters just before the T at the engine ..............
Well I found my problem. I purchased a 12oz. bottle of octane boost because I couldn't find any perineum non ethanol gas in town. The nailhead is high compression and I figured I would start with premium to see how it worked. The boost was from my local Dollar store. Now I know why it was only a buck. 12oz. of H20. I drained the tank, replaced the mechanical fuel pump and bypassed the electric. The mechanical was full of water when I drain that. 10 gallons of fresh gas with a can of Seafoam should do the trick. It started but would not idle or accelerate with out dying. Pulled the top off the Q jet and replaced the fuel pump seal. Runs great now. The photo is of a gallon jug with some of the gas I pumped off the bottom of the tank.
Surprised me to seeing how everything is new. The fuel pump was not holding the gas in the line up to the carb so I knew the check valve was probably stuck open. I had already bought a replacement mechanical pump and found the water when I took the old one off, even though it was just installed earlier. I also had noticed there was an excessive amount of water coming from the exhaust when I first fired the motor and every time after that. It was more than usually comes from condensation in the mufflers and there was no antifreeze in it. I was amazed on how many things the water effected and had to be replaced.
Just a side note on pumps a rotatory pump will not flow when a mechanical pump is primary. Only the push/pull units will flow freely when not on. Rotatories need a bypass with a check valve.
I went through 3 of those little electric pumps at the tank when I first built mine. They'd just quit! So, I went against my better judgement and installed a mechanical pump at the engine and I could see the gas boil in the clear plastic filter (next to the head), but it never quit. It's not supposed to do that, but it works. I also installed an in-line bulb primer for a boat at the tank for priming the carb. Just a few squeezes and I'm ready to go.
My only question would be is how much line pressure would those rubber bulbs stand before they expand and will they stand up to ethanol?
Ain't rocket science. Get an electric pump that you can "blow" thru. Mount it next to the tank. Use a 3-way toggle and power the pump from either the start side of the solenoid or the "hot" side of the solenoid. That way you can, with the toggle in the middle, have no electric pump or toggle on the start side you can have the FP only during start sequence or toggle in the run position have FP full on all the time.
It's in line closest to the tank and isn't under pressure. (ahead of the mechanical pump) It's been there for 7 years now, no problem with ethanol.
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