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3800 swap fuel pump ?? by Lou6t4gto
Started on: 03-29-2019 11:46 AM
Replies: 6 (657 views)
Last post by: Lou6t4gto on 04-01-2019 01:55 PM
Lou6t4gto
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Report this Post03-29-2019 11:46 AM Click Here to See the Profile for Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
guys bringing me his "unfinished" 3800 swap to "make run". He has Installed a" 1 line" Corvette FUEL PUMP, is that going to work ??? or am I going to be dropping the tank again ? Thanks
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Darth Fiero
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Report this Post03-30-2019 10:05 AM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
Not sure what you mean by a "1 line" Corvette fuel pump. Most in-tank pumps only have 1 outlet unless it was designed to be part of a module/canister that had a venturi pump integrated into the bottom of the canister. (Venturi pumps are designed to use a small jet of fuel output by the main fuel pump via a secondary port to scavenge fuel from the bottom of the tank to fill the canister, so in-tank baffling could be deleted.)

If you are doing a 3800 swap, you are always going to need some kind of fuel pressure regulator and that is going to need a return line to the tank, unless you find a regulator that mounts inside the tank and dumps relief pressure directly back into the tank. Note that any such in-tank regulator would probably be a fixed type, not one that references vacuum or boost.

All 3800 Series 2 PCMs are factory programmed to assume a vacuum/boost referenced fuel pressure regulator is being used. Series 3 engines had returnless fuel rails and thus used a fixed fuel pressure regulator. If you want to use a fixed fuel pressure regulator with a Series 2 PCM, some custom tuning work may be required to get it to work correctly with a fixed fuel pressure system.

Modern GM vehicles have done away with the conventional fuel pressure regulator and replaced it with an active fuel pressure control system (usually consisting of a fuel pump control module and feedback pressure sensors). None of this hardware will work correctly with a 3800 PCM because 3800 PCMs are not designed to communicate with FPCM's.

NOTE: most "Corvette" fuel pumps I've seen (like the ever-popular EP-376) are not rated to supply the high volume of fuel flow the 3800 SC engine demands at the 60+ psi of fuel pressure the 3800 SC engine usually runs at with full boost. Whenever you do a 3800 SC swap, you need to make sure you are using a fuel pump capable of supplying the engine with the volume of flow of fuel it needs at the elevated fuel pressure levels unique to boosted engines. The EP-376 pump is not rated for this and, depending on the manufacturer, could be woefully inadequate for the task of supplying enough fuel to a 3800 SC swapped Fiero. I used to recommend the EP-381 pump for stock or very lightly modded 3800 SC Fiero swaps, but it has come to my attention that some aftermarket manufacturers of these aren't making a quality pump and it too may be inadequate for the task. A true safe bet is to only use an aftermarket performance pump - like one of the many 255 LPH units available from quality manufacturers in your 3800 SC swap.

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[This message has been edited by Darth Fiero (edited 03-30-2019).]

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Spadesluck
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Report this Post03-30-2019 01:01 PM Click Here to See the Profile for SpadesluckSend a Private Message to SpadesluckEdit/Delete MessageReply w/QuoteDirect Link to This Post
I am guessing he meant "in line" fuel pump.
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Lou6t4gto
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Report this Post03-30-2019 02:25 PM Click Here to See the Profile for Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
from what I'm" told", a corvette pump" in the tank" & 1 line to a 1 Line series 3 fuel rail ON a series 2 3800SC. No return. ecm was NOT altered for that.
Such Fun figuring out what the previous people DID. LOL
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Darth Fiero
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Report this Post03-31-2019 11:36 AM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Lou6t4gto:

from what I'm" told", a corvette pump" in the tank" & 1 line to a 1 Line series 3 fuel rail ON a series 2 3800SC. No return. ecm was NOT altered for that.
Such Fun figuring out what the previous people DID. LOL


It would still need to have a fuel pressure regulator somewhere, be it in the pump itself, in the tank, or somewhere outside of the tank.

Don't confuse this with a pressure relief valve that is integral to some fuel pumps. Such pressure relief valves are configured to vent only at very high pressures (too high for a 3800 SC application) and are not designed to be used as a pressure regulator.

So what is the fuel pressure with the pump running and engine off?
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viperine
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Report this Post04-01-2019 01:02 AM Click Here to See the Profile for viperineSend a Private Message to viperineEdit/Delete MessageReply w/QuoteDirect Link to This Post
Sounds like a headache. Drop the tank, install a normal pump (ep381?) And do it right. Charge the customer accordingly.

Mechanics already have enough problems with customers that neglect issues. Swap jobs should be done with proven, known results for simplicity.
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Lou6t4gto
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Report this Post04-01-2019 01:55 PM Click Here to See the Profile for Lou6t4gtoSend a Private Message to Lou6t4gtoEdit/Delete MessageReply w/QuoteDirect Link to This Post
my thoughts exactly. I gave him a engine/trans with wiring ON the cradle (plug in & run) (ALL His Parts to begin with), and him and a "friend" decided to change things, now I'm getting it back to "Make run". Thanks
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