C4 carb conversion - Fuel System
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8th Gear
Joined: Dec 2022
Posts: 8
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From: Michigan
C4 carb conversion - Fuel System
I'm in the process of finishing a 1984 C4 cross-fire to carburetor converstion, but I ran into a problem with the fuel system. I had to replace the fuel sending unit due to some frayed wires, and I'm unsure if I can simply plug the new sending unit and pump into the old wiring harness that is back by the fuel tank, and just connect a three port fuel regulator before the carburetor to lower the fuel psi, and just have a return fuel line connected, which is what I am hoping I can just do, or if I have to totally wire a new system. I have found some other information from research and recommendations, on people doing similar conversions but instal a totally different fuel pump circuit in which they wire from the batttery, oil pressure switch to a relay, and then to the fuel pump and to a toggle switch. I feel this is doable, but I think Id have to cut the wiring on the brand new fuel sending unit, which Id rather not do, and thats a lot of wiring installing and Im no electrition, I'd rather not do if I can simply put a regulator on there and a return line. I can post any pictures or information needed further. I can also use the stock fuel pump too aswell correct, so long as I have the regulator connected? Thank you.
Drifting
Joined: Mar 2006
Posts: 1,263
Likes: 188
From: Wabasha Mn
I'm in the process of finishing a 1984 C4 cross-fire to carburetor converstion, but I ran into a problem with the fuel system. I had to replace the fuel sending unit due to some frayed wires, and I'm unsure if I can simply plug the new sending unit and pump into the old wiring harness that is back by the fuel tank, and just connect a three port fuel regulator before the carburetor to lower the fuel psi, and just have a return fuel line connected, which is what I am hoping I can just do, or if I have to totally wire a new system. I have found some other information from research and recommendations, on people doing similar conversions but instal a totally different fuel pump circuit in which they wire from the batttery, oil pressure switch to a relay, and then to the fuel pump and to a toggle switch. I feel this is doable, but I think Id have to cut the wiring on the brand new fuel sending unit, which Id rather not do, and thats a lot of wiring installing and Im no electrition, I'd rather not do if I can simply put a regulator on there and a return line. I can post any pictures or information needed further. I can also use the stock fuel pump too aswell correct, so long as I have the regulator connected? Thank you.
P S - Walbro Pumps USA Made
Last edited by wilcar; Apr 12, 2023 at 12:47 PM.
Drifting
Joined: Mar 2006
Posts: 1,263
Likes: 188
From: Wabasha Mn
Yes they did and you can buy these china built fuel pumps as cheap as $15 on rockauto.com The USA made Walbro 5ca401 pump has 12 psi so will need a regulator and is about $90 shipped from Summit Racing. I still have the factory 55 psi pump in my carbed 84 and will be changing to the walbro pump soon.
