Dual Tank questions

[jman340]

Hello,
I'm pretty new here and have a few questions. I have an 86 GMC 1500 short bed that had dual tanks. Previous owner installed a Holley projection system that is a mess, and I plan on swapping over to a carb set up. My truck has dual tanks with a switch on the dash to toggle between them. There are dual electric fuel pumps mounted right near the tanks which the switch also toggles. I hope to remove the elec pumps, add a mechanical and plumb to the carb. As this truck is not driven regularly, I may remove one of the tanks, or at least cap it. On a single tank truck, which side is the tank on, or are they in a different location all together. If I remove the tank, I want to make sure that I remove the secondary as someone else may be able to use it. Is there any other wiring or issues i should be aware of that I perhaps haven't taken in to consideration?
Thanks
John

 

[crazy4offroad]

IMO I would keep the Holly fuel injection system if I were you, but if you're dead set on it go for it. It would be personal preference which tank you want to keep, the driver's side is the only one I have because when I get out of the truck to fuel up, it's right there, no need to walk around to the other side. Left/right tanks are identical to look at them, only thing that designates them side to side is the filler neck hose and mounting brackets. Only other thing is dont try to run a carb on a high pressure fuel injection style fuel pump, it will flood out. You could keep one of the pumps and use a pressure regulator to cut it down to the 5-10 psi a carb needs to run. By the way if you go to sell that Holly system post it up here in the Buy/Sell/Wanted section, I'm interested.

 

[jman340]

The instal of the projection was pretty much a hack job, so the main reason is to clean things up a bit, plus replace it with something I'm very familiar with tuning, and I know will be reliable. I do plan on taking out the electric pumps and run a mechanical. The main reason for the tank removal is because the truck will not be driven regularly, there is less chance that the remainder of the gas in one of the tanks ends up sitting for months or more at a time. I would also thing that it would take a little bit of weight out of the truck.

 

[GreaseDog]

if you're **** it for weight reasons, leave the passenger side tank.

the injection system actually has more positives than negatives, i'd fix the hack job if it were me.

 

[bucket]

I would fix the hack job too. I would also keep the dual tanks, a single 16 gallon tank just doesn't go that far.

You can leave either tank, they are the same. The mounting brackets are also the same. The sending units are technically side-specific, but they will work on either side. 70's trucks with single tank had it on the pass side, while 80's trucks had it on the driver side. Basically, there's no wrong way to do it.

 

[WHEELMAN]

I HAVE A LONG BED-78 with one tank-it is on the passenger side..my 86 gmc short bed.has the dual tanks.one on each side..they do not hold much gas.so if you were going to drive it.on trips..

keep both tanks..i use the left side tank.easy to put gas in.with out walking around..get rid of that.electric crap and go too old school..it is cheaper and reliable.

easy to work on and tune your truck..that electronic crap..is fine for a race car.that needs to go super fast.and has a trailer right there to put it on when it breaks down..

i have bought these two..old school pickups.to back up.my two newer electronic vehicles.that break down every time i turn around..electric fuel pumps.in the tank.where you cant get too them..is the biggest.rip off.that has ever been built.

some people are installing a tank out of the surburans..and mounting it.at the back.between the frame..too have one tank.that set up.is on line some where.

 

[randyb]

help

I'm redoing an 83 Chevy k20 4x4 I need to know how to know what fuel sending unit to use do I need a 3 outlet on the passenger side and 2 outlet on the driver side or how does that work, the originals are not on the truck

 

[chengny]

I need to know how to know what fuel sending unit to use

Try AC Delco part FLS1001 for the production (LH) side tank and FLS1002 for the auxiliary (RH) side tank - I believe those are the correct numbers.

do I need a 3 outlet on the passenger side and 2 outlet on the driver side

That depends on a couple of things. Like, how environmentally conscious you are and whether or not the evaporative emissions system is still installed and functional.

Both tanks were originally fitted with 3 port senders. The middle port was used to vent the tanks to the evaporative emissions control system. Whether or not to use the middle port is your call.

The outer two ports are for fuel pump supply and return (the bigger one is supply to the pump and the little one is the return from the pump).

Matter of fact, if you are running a two port fuel pump (suction & discharge only - no return), you don't even need to use the small sender port.

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If you can source two port senders - and they are cheaper - go for it.

Attached are the parts illustration and list for the rear fuel delivery system that applies to your situation:

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As a bonus - if you eliminate the vent line - you can get by with a 3 port tank select valve rather than a 5/6 port one.