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73-87 Chevy _ GMC Trucks => Fuel Systems and Drivability => Topic started by: harvirish on October 27, 2020, 07:40:13 PM

Title: Retrofitting Dual Tanks - Sender Qestions
Post by: harvirish on October 27, 2020, 07:40:13 PM

I am installing a dual tank system in my 87 R20, Originally it just came with a left side tank. I have two 87 tanks and Im loking to buy new sending units. Anyone have any idea what Im going to need. When I look them up there are sending units for the right, for the left, for accessory tanks and for main tank with accessory tank. I cant determine the difference in these. Any suggestions?

Title: Re: Retrofitting Dual Tanks - Sender Qestions
Post by: bd on October 27, 2020, 08:25:40 PM

Just variations in terminology.  The left tank is the main tank.  The right tank is the auxiliary tank.  The primary difference between the left and the right tank pickup units (sending units, senders) is the clock orientation of the tubes exiting the top of the units and the swing of the float arms.  With TBI, you'll need two 3-port pickup units and one 6-port selector valve.  Don't forget the dash mounted tank selector switch.  Both the switch and the valve use molded electrical connectors to attach the wiring. 

Title: Re: Retrofitting Dual Tanks - Sender Qestions
Post by: Mike81K10 on October 27, 2020, 09:07:07 PM

Left and rt fuel sending units are different. The picture is from an 81 K10 and I believe yours will be a little different because you have in tank pumps. However if you notice the hose connections face different directions on the two.

Title: Re: Retrofitting Dual Tanks - Sender Qestions
Post by: ehjorten on October 28, 2020, 09:13:51 AM

Pollack is who made the selector valve. http://products.pollakaftermarket.com/viewitems/fuel-selector-valves/light-truck-6-port-motor-driven-valve

Title: Re: Retrofitting Dual Tanks - Sender Qestions
Post by: harvirish on October 28, 2020, 09:58:12 AM

Thanks for the help!! I'm sure I'll be asking more questions about the fuel system when I get a little further along.

Title: Re: Retrofitting Dual Tanks - Sender Qestions
Post by: Mike81K10 on October 28, 2020, 11:33:35 AM

The fuel tank selector valve picture with the cover removed is attached. There is a cover that protects it.

Title: Re: Retrofitting Dual Tanks - Sender Qestions
Post by: CreightonC on November 09, 2020, 08:24:42 AM

Amazon has the original dash switch (AC Delco) for about $13.00, the part number is D7089C for the 87 TBI one. I bought one for my son's truck.