Electric Fuel Pump Conversion
Thread Starter
Heel & Toe
Joined: Nov 2012
Posts: 15
Likes: 0
Sure, remove the pump and replace with line/tubing to complete the pickup. Just use "in fuel" compatible materials.
The fuel dripping into the engine is not from the electric pump. It could be a number of things:
1 trash/material in the needle & seat - need good filter
2 worn needle & seat
3 fuel pressure too high
4 float setting too high
5 percolation - fuel boiling -
The fuel dripping into the engine is not from the electric pump. It could be a number of things:
1 trash/material in the needle & seat - need good filter
2 worn needle & seat
3 fuel pressure too high
4 float setting too high
5 percolation - fuel boiling -
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
I have installed a manual fuel pump on the engine. It's pulling its fuel through the electric fuel pump that's in the tank and now the fuel is dripping into the carburetor when I shut the engine off. It won't start back without pushing the accelerator to the floor. I want to remove the electric fuel pump.
Do you have a fuel return???
What type of carb???? It makes a difference on if a fuel filter can be installed in it or not.
DO you have a fuel filter installed.....of so...where is it installed.
If you remove the fuel pump...you HAVE TO have that fuel filter sock in the tank to catch the primary crap that can be in the tank. Getting a 1978-1981 sending unit is ready to go. DO NOT try to install a paper element filter in the tank. Not a good idea...I have seen it done and it does not work for long.
Does you fuel tank...after you have driven it...get pressurized...so when you go and remove the fuel cap...it has pressure that is released when the cap is removed. I have encountered cars that leak fuel due to the vapor return line is plugged...and the fuel cap is designed to allow air in...but not out. So the tank gets pressurized and it can leak pasty the needle and seat if the pressure is high enough. I have had carbs dripping and when I go and remove the fuel cap...the dripping stops instantly...and the pressure in the tank was rather severe due to the baby powder I placed around the fill cap...blew and put baby powder dust in the air around the fill cap.
DUB
Drifting
Joined: Jul 2007
Posts: 1,889
Likes: 23
From: Kansas
The original 1982 has around 40 #'s of pressure, pull out the fuel sending unit & change the pump to a 7 # pump, or install a fuel pressure regulator.. The 1982 also has a filter on the side of the frame under the passenger floor board, from the factory. Have a great one. Gene
Drifting
Joined: Mar 2006
Posts: 1,263
Likes: 188
From: Wabasha Mn
82 and 84 pumps only put out 15 psi. A lot easier just to use the stock 15# pump and use a return style regulator like the Mallory 4309. Pulling fuel through a dead pump with a mechanical pump is not the most ideal solution. If you are set on using a mechanical pump then get rid of the intank pump and use a good fuel sock on the the new suction tube. I listed the airtex 6 psi pump on this thread that you could use as the intank replacement pump if you choose to go that route.
Race Director
Joined: Apr 2009
Posts: 19,294
Likes: 2,754
From: Charlotte NC
This may not apply or be needed but it is something that I take into account when modifying a fuel system.
One thing that has not been touched on in this discussion about fuel return is WHERE to have the fuel return.
I prefer on a C3 is to have the fuel return at the mechanical fuel pump area like the factory had originally. On the new Corvettes...they only have one fuel line going to the engine because the fuel filter has the return in it and it is back in the rear of the car...and this is fine BECAUSE GM has taken steps in adding heat shielding and what have you to better protect the fuel line from heat...versus the C3 era.
I am not a fan of a fuel line that I can infra-red thermometer check and it is hot as all get-out....that allows fuel to linger in it because the fuel return is way back in the rear of the car. UNLESS steps are taken to protect this fuel supply line from heat...and most people do not do this...especially when headers are installed and the performance changes. I have had two Corvettes in my shop and are basically the same except for one having headers and drive them the same amount of time and distance and the temps on the frame where the fuel line is secured is much higher than the engine with cast iron manifolds.
I know it may be a bit paranoid...but some changes I applied to many C3 Corvettes due to a high heat issue on the fuel lines helped out. Kinda like a starter blanket on your starter when you change to headers...regardless if they have a coating or wrap on them or not...it can aid ina possible problem in the future.
DUB
One thing that has not been touched on in this discussion about fuel return is WHERE to have the fuel return.
I prefer on a C3 is to have the fuel return at the mechanical fuel pump area like the factory had originally. On the new Corvettes...they only have one fuel line going to the engine because the fuel filter has the return in it and it is back in the rear of the car...and this is fine BECAUSE GM has taken steps in adding heat shielding and what have you to better protect the fuel line from heat...versus the C3 era.
I am not a fan of a fuel line that I can infra-red thermometer check and it is hot as all get-out....that allows fuel to linger in it because the fuel return is way back in the rear of the car. UNLESS steps are taken to protect this fuel supply line from heat...and most people do not do this...especially when headers are installed and the performance changes. I have had two Corvettes in my shop and are basically the same except for one having headers and drive them the same amount of time and distance and the temps on the frame where the fuel line is secured is much higher than the engine with cast iron manifolds.
I know it may be a bit paranoid...but some changes I applied to many C3 Corvettes due to a high heat issue on the fuel lines helped out. Kinda like a starter blanket on your starter when you change to headers...regardless if they have a coating or wrap on them or not...it can aid ina possible problem in the future.
DUB
Drifting
Joined: Mar 2006
Posts: 1,263
Likes: 188
From: Wabasha Mn
Good point Dub, lots of engine heat with headers that can heat up fuel lines and mechanical pumps causing percolation problems. I have a 455 in my 65 Gto that I used to drag race when I lived in Tampa. I had a electric inline pump in the rear and a mechanical pump. I was having percolation problems and we found that the mechanical pump was getting so hot the fuel was boiling. We eliminated the mechanical pump and problem solved. I cannot speak for 1982 carb conversions but on an 84 a lot of us have percolation problems. A 1/2 inch minimum carb spacer is required and due to hood clearance a shorter air filter is required. I mounted a small cowl induction scoop to help exhaust some of that nasty engine heat and that solved my issue.
