73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: werewolfx13 on October 16, 2007, 11:09:14 am
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I'm kinda poking at installing dual tanks in my '83 swb. I don't have a right hand filler door, nor do I want to swap beds/bedside or cut a hole in this bedside, and I can't have a filler inside the bed, so I'm trying to think of ways to fill a passenger side tank from the drivers side tank. I've thought about an electric pump just for cross filling, but I'm not sure how I'd go about connecting it. I'd like to go with dual polyethylene tanks, but I've also considered going with new steel tanks and having a machining/fabrication shop install some fittings near the bottom of both tanks to run a crossover hose across. I'd really like to have rust-proof tanks without shelling out tons of cash for SS tanks though. Also, a rear mounted single larger tank is out of the question, because my hitch interferes with the reccomended mounting area, and again, because I can't have a filler IN the bed...My bed gets used and quite frequently is left full of stuff.
A little bit of extra info: my truck will be running an aftermarket TBI system, and will have electric in-tank fuel pump(s) on '87 sending unit(s). If I go the route of steel tanks with fittings welded in near the bottom, I can probably get by with one pump, and just let the fuel draw from the right into the left as its used, but I don't really like that idea all that much.
I don't mind having a separate fuel gauge for the passenger tank, atleast for the time being...If I ever buy a set of dakota digital gauges, I'll probably want to stick with the single gauge..Though, a second gauge connected to JUST the passenger tank might be useful for using an electric pump to pump the fuel over..
The TBI kit I'm planning on has a dual tank kit available that includes a second in tank pump, relay, tank switch, inline filter, and looks like it includes a 6 port tank selector valve, and a wiring harness.
I know there are other posts that are vaguely similar to this topic, but I hope to get some centralized info for myself and anyone else that's given dual tanks a thought but didn't want to modify their bed to fit the 2nd tank filler neck.. And I don't like bringing year+ old posts back from the dead to answer other questions.
Thanks in advance ;)
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If your tank is on the left and you are installing a tank on the right, make your right tank the primary tank with your in tank fuel pump. Install a 12v electric feed pump from the LH tank to the RH tank. So esentially fill your left tank, turn on the pump with the key on make sure you watch the gauge so you don't overfill the RH tank. Then fill your Left tank up again. That's one redneck way of doing it :P
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Yeah I suppose that would work too. ;D
I may have to give that some serious thought.. an extra '87 sending unit and the dual tank kit for the TBI system would end up being an extra $300+ even if I bought the dual tank stuff separately and cheaped out on the pump. :-\
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run a pipe over to the "new" tank between the framerail and bed and tie into the old tanks filler neck at the lowest point that way when the old tank is full and it starts filling the neck it will spill over to the "new" tank.
Or you could just run the pipe over and turn it towards the wheel opening and fill it from there. My Crew is like that since it used to have a flatbed on it and they put a single tank bed on it.
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Hmm, I hadn't thought about putting the filler neck in the wheel opening..I'll have to take some measurements today if it quits raining, but I think my 31x10.50 winter tires would interfere with it at stock 2wd ride height.
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My '75 SWB 4x4 has a step-side box from a '95 on it that only comes with a driver side fill door and I have dual tanks. I have the stock style tank selector valve and switch from Borg Warner and an in-line electric fuel pump for my GM TBI(so only one pump) and it works pretty well. I did something like as above mentioned by running a pipe across the frame to the passenger side tank but I cut a hole into my existing filler neck high enough up so another short pipe could be welded on to it. That way I can fill whatever tank I want. Only problem with the whole setup is the passenger side tank fills a bit slower due to the fuel having to run almost flat across the frame to the other tank.
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I've narrowed my viable options down..I'm going to do it right when the time comes to actually try it, so I'm going to use a fuel pump in each tank with a selector valve (if for no other reason than if one pump goes bad, I can switch tanks). Now, I've just got to decide between trying to tie into the filler neck as described (any pics of this would be nice, I'm having a hard time visualizing tieing in a pipe thats as big as the filler neck is), or just using a cheap external pump as a crossover. I'm leaning toward the external pump. My only hangup at the moment is my lack of knowledge of what all the outlets on the sending units are for..on an '87 sending unit w/ 3 outlets, I assume one is the feed to the throttle body and one is the return, but whats the other one for? Could I use one of them on the drivers side to tie into for the external pump, or do I need to install a bulkhead fuel cell adapter near the bottom of the tank (they'll both be poly tanks). And what about the passenger side, same thing, would I be wiser to use a bulkhead fitting, or an outlet on the sending unit?
Everyone's been a great help so far, I really appreciate the input I've gotten thus far. Thanks again.
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I'll try to snap some pics of the fill neck I made and post them here as well as the piping across the frame, but it won't be until Thursday or Friday as it is dark out now and I won't be home tomorrow night. the pipe I used to tie into the stock filler neck was 1 1\2 inch electrical conduit cause it's cheap and the only bad thing is be careful when welding or brazing it to the filler neck as the galvinized coating is toxic.
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The 3 lines on your fuel pump sending unit assembly are
1. Large (3/8") fuel feed hose to engine via slector valve.
2. Medium (5/16") fuel return line from engine via selector valve.
3. Small (1/4") fuel vapor line connected to a "T" or "Y" fitting and feeds up to the fuel vapor cannister on the drivers side of the of the engine compartment mounted to the core support next to the radiator.
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Sweet, thanks a lot to both of you, I'd forgotten about the vapor line. If I go the inline pump route, it sounds like I'd be wise to install some bulkhead adaptors in the tanks..poly tanks should be easy enough to drill to install them into, I just have to make sure I can get my hand and/or a wrench into the tank to tighten the lock nut.
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Just remembered a VERY IMPORTANT ITEM be sure to change ALL rubber fuel lines on the vehicle to ones rated for fuel injection otherwise your stock hoses will rupture from the additional pressure of the fuel injection setup.
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Yep, already planned on it. I may actually replace all the metal lines with new aluminum or SS lines too when the motor and trans are out so I don't have to worry about them rusting out.