The 1947 - Present Chevrolet & GMC Truck Message Board Network - View Single Post - 1973-1991 Dual fuel tank systems theory of operation

**hatzie** · 01-04-2018, 02:23 PM

The vapor lines are tiny.
I'd keep the charcoal canister. It'll keep the garage from smelling like gasoline in the summer. You can simplify to a 1970's three hose can. Vapor, Ported Vacuum to run the valve, and SAE J30R7 purge hose teed into the PCV valve hose.

If you're installing EFI you'll want to have the baffled R/V 10-30 series 1987-1991 tanks. Get the TBI senders for the later tank that already have return lines... That's what I did with my 76.
TBI had the in-tank fuel pump hanging from the sender.

01-04-2018, 02:23 PM	#4
hatzie Moderator Join Date: Oct 2008 Location: Wentworth, NH Posts: 4,913	Re: 1973-1991 Dual fuel tank systems theory of operation The vapor lines are tiny. I'd keep the charcoal canister. It'll keep the garage from smelling like gasoline in the summer. You can simplify to a 1970's three hose can. Vapor, Ported Vacuum to run the valve, and SAE J30R7 purge hose teed into the PCV valve hose. If you're installing EFI you'll want to have the baffled R/V 10-30 series 1987-1991 tanks. Get the TBI senders for the later tank that already have return lines... That's what I did with my 76. TBI had the in-tank fuel pump hanging from the sender. __________________ 1959 M35A2 LDT465-1D SOLD 1967 Dodge W200 B383, NP420/NP201 SOLD 1969 Dodge Polara 500 B383, A833 SOLD 1972 Ford F250 FE390, NP435/NP205 SOLD 1976 Chevy K20, 6.5L, NV4500/NP208 SOLD 1986 M1008 CUCV SOLD 2000 GMC C2500, TD6.5L, NV4500 2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263 2009 Impala SS LS4 V8 RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials... 1973-1991 GM Light Truck Service, Unit/Overhaul, Wiring Manuals, Parts Books and Some 1968-1999 GM Service Training textbooks in PDF 1988-1998 GMT400 CK service manual project 1988-1993 GMT400 CK parts books. 1967-1972 GM Light, Medium, & Heavy Truck Service Manuals in PDF Please include at least the year and model in your threads. It'll be easier to answer your questions. And please let us know if and how your repairs were successful. Last edited by hatzie; 04-16-2018 at 02:56 PM.