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additional fuel tank

Discussion in 'Chevy Trucks' started by gcspray, Feb 2, 2002.

  1. gcspray

    gcspray Junior Member
    from NC
    Messages: 3

    My 87 Chevy Crewcab Duelly is used primarily to tow a 36 ft 5th wheel. A few years back I added an 80 gallon in-bed fuel tank/tool box combination. I installed a 6.5 KW Onan Generator in the rear of the truck, through an access hole that we cut over the area where the spare tire would have rode if it had one. A machine shop built a steel cabinet with a 1/4 inch thick lid, that fits flush into the bed floor. The gen set pulls it's fuel supply from the large tank, and it's starting power from the truck's battery. The whole thing works perfectly.

    The problem is utalizing the fuel to run the truck's engine. The truck has the TBI system, with tank mounted high pressure fuel pumps. For several years, I have used a permanently mounted electric fuel pump/ solonoid switch with an inline filter to transfer fuel from the large tank to the right hand saddle tank. The whole contraption is wired through a holding relay, that trips off if the brake lamps are activated, or if a motion switch is activated, to prevent accidental dumping of fuel if a wreck ever occurs, and fuel lines are ruptured.

    My goal is to connect the 80 gallon tank directly to the engine via a second OEM 6 port selector switch/valve. My question is: Does anyone have knowledge of an after-market electric fuel pump which can be mounted in the fuel system, between the tank and the engine which will provide adaquate fuel pressure and volume to the TBI system.
    Thanks,
    Charles
     
  2. gcspray

    gcspray Junior Member
    from NC
    Messages: 3

    UPDATE

    After talking with the local Chevy dealer, I was able to find out some essential information regarding the fuel requirements of the 87 and 88 454 with TBI. The TBI system on 87 and 88 Chevy 1 ton's with 454 engines are low pressure systems which function between 8 and 13 pounds of pressure, unlike current fuel injection systems which function at 40 PSI, and some which function at 60 PSI.
    Since the system is a low pressure unit, the best fuel pump match I could find is a Holley unit designed with an adjustable regulator set at 70 GPH and 14 PSI. It was available overnight from Advance Auto at $117.00. In a temporary test instalation, the regulator was easily recalibrated to 12 PSI, and maintained 11 PSI with an open line. The next step is the fuel change-over valve, a "dealer item only" part. The only snag is going to be finding a wiring harnase for the fuel change over valve. I will search the local wrecking yards first.
    My plan is to mount the second change-over valve next to the original valve, connecting the output ports of the original valve to one side of the input ports on the new valve. The output ports of the new valve will supply the engine. The remaining input ports on the new valve will be connected to the aux fuel pump, then the aux tank. The truck will have two change over switches on the dash, one to change between the aux tank, and the saddle tanks, and the other to change between saddle tanks. The power to run the aux pump and fuel guage connection will be switched with the valve, getting it's power from the existing circuit, with the momentum switch and other safety cut-off's intact. I still need to find a wiring diagram for the stock fuel change over system. Any suggestions are appreciated.
    Charles