EFI Sending Units

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Bama69

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87 v10 4wd - I’m currently running the stock 350 with TBI. In the near future plan on replacing it with a 383 stroker with EFI. I need to replace the sending units and wondering if I can run the TBI with a higher fuel flow sending unit that will be needed for the EFI? If so, are there any other mods I would need to make such as fuel lines, fuel filter, dual tank valve, etc.?
 

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You just change the pump and screen. An Ep381 will probably due it. But you'll need to compare what your EFI wants VS. What an EP381 can provide.
 

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Yeah, people upgrade to the TBI sending units for their high pressure EFI swaps that require high pressure pumps. You just need pumps for the sending units you already have.
 

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Yeah, people upgrade to the TBI sending units for their high pressure EFI swaps that require high pressure pumps. You just need pumps for the sending units you already h
I really haven't dealt with fuel systems, but would like to eventually, switch things to EFI; but I don't want to do it in all one step. So, I could add the pump to the sending unit in my old tanks (put them in the new baffled tanks I have). My 85 k10 runs a Quadrajet. I know I would have to add a regulator down the line and probably swap out the selector for highpressure..
 

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I really haven't dealt with fuel systems, but would like to eventually, switch things to EFI; but I don't want to do it in all one step. So, I could add the pump to the sending unit in my old tanks (put them in the new baffled tanks I have). My 85 k10 runs a Quadrajet. I know I would have to add a regulator down the line and probably swap out the selector for highpressure..
I have used an EFI sending unit and just cut off the end of an older carb sending unit that the filter attaches to. You can use the short section of fuel line that would connect the pump to the sending unit and instead use it to connect the end with the fuel sock on it to continue to use the carb pickup, while having the future capability to connect an EFI pump when you are ready. I have also had an EP 381 in my tank for almost a year while still drawing through it with my mechanical pump. I just don't have the wires hooked up to the electric pump. When its hot and I'm pulling a load the added restriction will cause it to start to vapor lock, but just normal daily driving it works fine.
 

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I would think that a TBI tank and sending unit with a TBI pump and a bypass regulator could feed a performance carb type setup, but isn't really needed if you have a mechanical pump that works. I would say that an in tank TBI pump would beat an external fuel pump any day for longevity and consistency. Drawing through a dead TBI sender as discussed above works too, but doesn't gain anything. If, however, you need to overhaul the fuel system anyway, then yes, running an 87+ sender, selector, lines, filter, etc can all be a reasonable step that can work with the current setup and be ready to switch to high pressure pump for EFI in the future.

For reference, the fuel flow of a carb vs TBI vs modern EFI really isn't that different by itself, I just depends on HP of the engine and if you are running a bypass regulator or not. The Pressure is what changes. Carbs run from 2.5-6.5 psi or so (just a general range, but it is single digits), TBI runs around 12 or so and may deadhead the pump at 25 or 30 psi, and "EFI" runs around 50 psi. Direct injection is a different animal, you feed the engine ~50 psi and the internal pump brings it up to 2-3000 psi or more, but no one runs those high pressure lines, they are part of the engine for all intents and purposes.
Most carb rated fuel lines and barb fittings top out around 10 psi as far as wanting to run at that pressure. The early TBI stuff was over the rating for typical fuel lines, so it was engineered and rated for up to 200 psi, really overkill but it made everyone feel much better about the "high pressure" fuel lines. Modern stuff is still rated for a lot more than we throw at it, still around 200 psi ratings. And that is definitely overkill, 200 is the service rating for nylon tubing, for instance, the failure rating is over 1000 psi, so we have safety factor on top of safety factor.

In short, unless you are going crazy, 87+ fuel lines and filters etc is all you ever need, and can be run on carb setups as long as you are aware of the minor stuff to hook it up correctly.
 

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Your truck being tbi, you could upgrade to the ep381 pump now and continue to run it tbi.
 

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Your truck being tbi, you could upgrade to the ep381 pump now and continue to run it tbi.
Correct me if I’m wrong, but you’d want a pressure reducer before the Tbi unit, as it’s internal pressure regulator will not act right with a 58 psi feed…

Maybe if you drill out the adjuster block or get different internals to deal with the higher feed pressure it could work-ish?
 

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Been running the ep381 pump for almost 30 years on tbi trucks with no issues.

It also puts out twice the volume of the tbi pump (155lph vs 75lph) Really helps the 350 and 454 trucks which starve for fuel with the tbi pump.
 

bucket

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Correct me if I’m wrong, but you’d want a pressure reducer before the Tbi unit, as it’s internal pressure regulator will not act right with a 58 psi feed…

Maybe if you drill out the adjuster block or get different internals to deal with the higher feed pressure it could work-ish?

The regulator will work fine, based on what others have done and told me over the last 20 years. There's two different thoughts on heat buildup in that situation though...

And to be clear, that pump is capable of more than 58 PSI. And so is a "45" PSI pump for other GM MPFI systems. Actual pressure is determined by the regulator.
 

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i port injected my 91 squareburban and left the stock pump in the tank as a lift pump, then added a big bosch inline pump all using the stock lines, been going north of 10 years.

just started modernizing a 78 c30 3+3 454, installed stock tbi saddle tanks with stock pumps and run them though a 6 port switch into a big bosch inline, then into a corvette return style regulator/fuel filter back though the switch to the tanks and forward through the stock line to a holley terminator x 4150, the 6 port switch switches the relays that run the respective lift pump and the dash switch swaps the sender to gauge and 6 port switch, it sounds complicated but its 4 fused bosch relays powering/switching 2 of 3 pumps that are all fired off the single fuel pump wire from the holley

i like name brand oem style pumps as they seem to have a better track record than aftermarket universal "performance" and can be had at any parts store if i am away from home/fab tools and work/giant tool set
 

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Your truck being tbi, you could upgrade to the ep381 pump now and continue to run it tbi.
My truck isn’t tbi. I’m in the process of redoing the fuel system. I started with baffled tanks. And I want to eventually run a Efi. So once I put the bed back on, I don’t want to deal with the tanks again. So that is my problem. Get Efi pump/sender combo and drop in for the eventual efi upgrade. Btw. It is a stock 350.
 

Brunc

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Been running the ep381 pump for almost 30 years on tbi trucks with no issues.

It also puts out twice the volume of the tbi pump (155lph vs 75lph) Really helps the 350 and 454 trucks which starve for fuel with the tbi pump.
An ep381 can produce 155lph? For some reason I thought it was a lot less. That may just solve the problem for me.
 

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