I've had it with this fuel system !

[DaveB]

My old 85 one ton needs some help with the fuel system. On every long trip its always a guess as to whether you can make it home without problems. Some history: original motor was a 454, two saddle tanks with a switching valve. My dad let some shop con him into solving his heating problems by pulling the 454 and dropping in an HT502. Of course this didn't fix his cooling issue but did start the fuel system issue. A 502 has no option for a mechanical fuel pump so he installed a Holley electric pump. Someone told him that he needed fuel filters before the switching valve and before the pump. There is also a filter after the pump before the carb and a little filter in the carb. If any of the filters on the sucking side of the pump (which is after the switching valve) get even a bit plugged the beast gets starved for gas and we sputter going up hills. So I've been living with having to regularly swap out the filters way before their time. We just got back from the Gorge and had troubles again. I had swapped out the two tank filters before the switching valve but not the one just before the pump. I made it home by swapping in a used filter but it acted up after a while. So I need to fix this once and for all. I am thinking that I need two fuel pumps one for each tank mounted as close to the tank as possible or I need to delete some of the filters. Are the pumps and switching valve so vulnerable that you need filters before each one ? I know in most fuel injected systems there is just a filter sock before the pump and a filter on the output side of the pump. One of my tanks is an aftermarket tank and I don't know if it has a filter sock in it so it may need a filter before the pump. I know most electric pumps are good at pushing gas but aren't great at sucking it out of a tank. The carb pump is not a high pressure unit and the TBI in tank pumps are also low pressure, could I use the in tank TBI pumps ? or just use two external high flow pumps ?
What do you think I should do ?

 

[mbryson]

I like your idea of using stock TBI in tank pumps. I'd assume you may need a pressure regulator before the carb.

 

[Tacoma]

hmmmm

I ran pretty much that same filter setup on the Chevelle 396 in my old work truck, with no problems-- Holley blue pump, after the valve... I like the idea of using TBI pumps, you could probably rewire the tank switch and get rid of the switching valve, which is what I ALWAYS have problems with. Add a regulator, and you'd be good to go... TBI runs at.. 9-14psi if I remember right.

 

[littlyota]

I will gladly take that 502 off your hands. Been looking for one for the boat.

 

[DaveB]

I will gladly take that 502 off your hands. Been looking for one for the boat.

That would probably make my wife happy but I do need something to tow the boat. I need to research the Holley vs TBI pumps to compare pressures and flow rate. For this engine flow is king.

 

[skippy]

The TBI pump is to high of pressure for a carb you definately need a fuel pressure regulator before the carb. I played this game with an 2wd one I had back in the day