TPI pump/tank/sending unit

[Blue85]

I am gathering parts for a TPI conversion and I have questions about the gas tank and pump after searching these forums. I understand that a TPI pump will fit in a TBI sending unit and I think I've even heard that the whole TPI sending unit will fit in a TBI tank. However, I have a carb tank (1985). Can I just get the sending unit from a TBI truck and drop that into my tank or will I need a different tank?

I like this idea because the sending unit will include a return line.

Has anybody had any bad experiences with an in-line pump mounted to the frame?

Thanks for helping me figure out my options.

 

[1979jimmy350]

The TBI unit will fit in your tank, but you won't have the baffles that the fuel injection tank has. I went the external pump route because it was more money to get a new tank and every thing, but i plan on a fuel cell in the near future to get rid of the fuel pick up issues

 

[Russell]

If you are using a non-efi tank, it'd probally be best to run an inline pump.

Like 79jimmy mentioned, the efi tanks have baffles in them that keep fuel around the pump, and make sure it is both kept cool with fuel, and not sucking air up if you take a hard corner / steep angle somewhere, stalling your truck out.

 

[plowboy77]

Hey, New guy here.
I have done what you are describing on my '76 K5. 1979jimmy350 and SierraClassic are both correct. The simplest/cheapest route to take is an inline pump for a TPI system. However, I decided to go the route GM intended and got an in-tank fuel pump for a TPI system (Thirdgen.org swears by Walbro pumps), a fuel tank sending unit from a '87 K5, (Ebay) and a new 31 gal tank with the internal EFI baffles from an '87 K5 (O'Reilly's). I needed a new tank anyway since mine had rust holes. The TPI fuel pump will fit the TBI sending unit. I have all the part numbers etc. if you need those.

Even with an inline pump there is a risk of sucking air on a steep climb or descent with only a partially full fuel tank. One option I ran across was to make a surge-tank for the system. A lift pump would fill the surge-tank (approx 1/2 gal tank +or-) and the high pressure pump would take it from the surge-tank and feed the fuel rail. Since the surge tank is much smaller fuel is less likey to run away from the outlet and less likely to starve the high pressure pump.
http://toyotaperformance.com/surge_tank.htm

Just some options I've researched!

 

[Blue85]

Thanks. I ended up using a K5 TBI tank and sending unit with a Camaro pump. I have run it really low on gas on the street and it doesn't sputter until I turn a corner in that last gallon. It seems to me I will have to keep some gas in the tank for off-roading, hopefully I will get to test that soon. It would be a shame to have it stall out on the sand dunes when my Q-Jet got me over them fine.

 

[Shiprekd]

Did you pick up a new tank? or used???

Used tbi tanks even in "good shape" have a reputation for their plastic baffles being broken - causing the exact condition you mentioned when relatively low on fuel. The aftermarkets (at least the ones I've seen and have in mine) use steel baffles that won't break.

I picked up a 22gl tank, tbi sending unit, and a camaro 1LE pump. Went to tube-tech and spent the bucks for the lines all the way to the TPI rail.

 

[Blue85]

I got a used tank, but it is an aftermarket unit. Instead of the plastic baffles, it basically has a steel pan on the bottom with a couple of small holes for fuel to drain into.