3V to Coyote; Return or Returnless-ish?

Discussion in '2005+ Mustang GT 4.6L Tech' started by mattjames, Nov 24, 2021.

  1. mattjames

    mattjames Junior Member

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    I'm still in the planning stages of swapping my 07 GT to a Coyote. I've had all the mechanical parts to do it over a year now.

    I've been spending hours the past couple weeks studying both car's wiring diagrams.
    My question is, if I wire the FPDM to Coyote PCM like factory, do I need the Coyote FPDM, or would the 4.6 FDPM work with the Coyote PCM? The wires are labeled the same from 4.6 to 5.0, just at different pin locations.

    I've already have the corvette fuel filter, fittings, etc to make it a return style since I originally planned to just do a return system and make it match in the tune, but if the 4.6 FPDM will work with the Coyote PCM ( or if the 11-14 plugs in, bonus, [EDIT: the connectors are labeled the same number but pins are different :/ ] ) I'll just make a new feed line from the stock filter to the Coyote rail and keep it returnless.
     
    Last edited: Nov 24, 2021
  2. jewc75

    jewc75 S197 Junkie S197 Team Member

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    If you ever decide to go boosted you will want a return system. Id do it now while its apart.
     
  3. Dino Dino Bambino

    Dino Dino Bambino I have a red car

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    If you're going to keep the Coyote N/A, keeping the fuel system returnless will be fine but if you're planning to boost it anytime in the future, it's better to convert it to a return style system from now and save yourself a lot of hassle later on.
     
  4. Juice

    Juice forum member

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    I am running the stock v6 fuel system, untouched. Just bought the fuel and vapor lines from the hard lines to engine, for a coyote. Ppl like to go overboard with fuel supply when it is totally unnecessary.
     
    eighty6gt likes this.
  5. mattjames

    mattjames Junior Member

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    So the 4.0 FDPM (guessing the 4.6 is the same) worked with the Coyote PCM??
    For now the engine is a stage 3 cammed first gen that probably won’t see boost very soon
     
  6. Juice

    Juice forum member

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    Yes, the 4.0 and 4.6 fuel system is the same based on my research. I only worked on the swap under the hood and dash. Never touched the tank or lines. (Except new stock fuel filter). Just hooked up the 2 circuits at the pcm. Fuel pump control and monitor, IIRC. It works 100% without issues and makes 400 at the wheels.
     
    mattjames likes this.
  7. OvalSports

    OvalSports Junior Member

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    I purchased the Power By the Hour electrical set up, and was told return style was a must with this configuration.
    We ran the return line and are getting ready to finish the plumbing. Is there any need to change the pump, or will running the 4.0 stock pump work with a factory boss engine?
     
  8. mattjames

    mattjames Junior Member

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    Probably because their harness has the fuel pump always running 100% duty cycle
     
  9. mattjames

    mattjames Junior Member

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    NA coyote requires a 155LPH pump minimum. Idk about Boss
     
  10. Juice

    Juice forum member

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    The stock v6 setup is plenty to feed it. ;)
     
  11. Dino Dino Bambino

    Dino Dino Bambino I have a red car

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    What's the V6 pump rated at? I know the 3V GT pump is rated at 148lph (238lb/hr) which is enough to support about 530 N/A crank HP (470rwhp) or 430 boosted crank HP (380rwhp). Since boosted 3Vs produce more than 380rwhp, a BAP is required to increase the voltage to the pump. A N/A Coyote would be fine on the stock 3V pump even with bolt ons (CAI, LT headers, '18+ intake manifold).
     
    Last edited: Nov 27, 2021
  12. Jack F

    Jack F Member

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    Just upgrade to a higher lph pump. Forget that 90s bullshit "boost-a-pump". It's right under the left side of the rear seat bottom.
     
  13. Juice

    Juice forum member

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    No, leave the stock pump, it is plenty. Forget that 90s bs of over specking fuel pumps. If by some strange reason is not enough, the CEL will let you know.
    V6 pump is same as GT, as far as I know. I already said that.
     
  14. mattjames

    mattjames Junior Member

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    Well the stock pump was never in question. I already have a 340 DW replacement ready that will be used. Engine going in made 489Whp on corn so I’m definitely not using the stock pump since it’ll also have 47lb inj as well. And since the 3V FDPM works itll most likely stay returnless
     
  15. OX1

    OX1 forum member

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    Like what hassle? I only have 7K on Roush boost-a-pump and 47's, but no issues as of yet, trapping what you see below.
     
  16. Dino Dino Bambino

    Dino Dino Bambino I have a red car

    Age:
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    The hassle of tearing the fuel system apart again later on if he decides to boost his Coyote swapped 3V S197 in order to convert the fuel system to a return style. It depends on what power level he's after. I'm guessing you're somewhere in the 550-600rwhp range which is still OK on a stock returnless system with a BAP.
     
  17. OX1

    OX1 forum member

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    Thanks for the clarification. Guess it really depends on how easy it is, with the car ripped apart already.
     
  18. mattjames

    mattjames Junior Member

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    I'm still a bit on the fence. If I'm replacing the pump anyway, it's just a bulkhead, a drilled hole, and a line away from being return. Not to mention, I already have those pieces ready.
     
  19. Juice

    Juice forum member

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    As far as I know, the main reason for return style system on boosted cars is the huge spike in fuel pressure when comming off boost. Pump takes a split second to adjust. You dont even 'need' to change anything in the tune. For return style, the pressure is just fixed in the tune vs varying the pressure for returnless. The variation is less than 3 psi from what I remember. My tune was set to return style, and ran returnless fine. But idle and low loads, pcm was pulling 10% fuel to compensate.
     
  20. Laga

    Laga Member

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    A return style system also lowers the temperature of the fuel. Which can help reduce the chances of detonation and vapor lock.
     
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