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Thread: Fuel dropping with the 450 walbro.

  1. #1
    Advanced Tuner =fast='s Avatar
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    Fuel dropping with the 450 walbro.

    I have a 2010 turbo 5.3, 76mm turbo, 16 lb's, boost cam, 83 lb's inj, and exhaust.

    With my flex fuel pump i was running out of gas at 5k rpm's fuel pressure was dropping around 32 psi. I switch to the walbro 450 and now the fuel pressure drops to 38 psi at 6k rpm's. What can it be that my fuel pressure its dropping? Should i change something on my desired pressure table?

    I been searching around but haven't found something to make the truck work. I don't want to mess with the desired fuel pressure before asking someone that know and have mess with this tables, I've files that are change settings on the desired fuel pressure table.

    Here's the file and a quick log of the fuel pressure.
    Attached Files Attached Files

  2. #2
    Advanced Tuner =fast='s Avatar
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    Have no one mess with the desired fuel tables?

  3. #3
    Senior Tuner LSxpwrdZ's Avatar
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    I'm not at a PC with HPT installed but what is the IDC? The 450 pumps require a lot of current and need a heavy gauge wire be run to them. One will not support the full capacity of 80lb injectors on a V8 application. In a perfect world the 450 pump will only flow 635lb/hr @ 58psi @ 14v at the pump.
    James Short - [email protected]
    Located in Central Kentucky
    ShorTuning
    2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
    2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400

  4. #4
    Advanced Tuner =fast='s Avatar
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    I'm not withy lap to right know but I remember seen 106 at 6k rpm's.

    How can I take of or disable the FPCM?
    Can I just remove it and run power and negative from battery?
    What would be better? Or would be even better a pressure regulator with a return like.
    The only thing keeping me back it's that I haven't see one so I can get an idea.

  5. #5
    Senior Tuner LSxpwrdZ's Avatar
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    The FPCM isn't currently the issue if you are running the injectors that hard. Sounds like you need more pump. Easiest way is to ditch the FPCM for a regulated system with more pump capacity or keep the FPCM and add a booster pump with it's own separate feed on a hobs switch. We have done it both ways with success.
    James Short - [email protected]
    Located in Central Kentucky
    ShorTuning
    2020 Camaro 2SS | BTR 230 | GPI CNC Heads | MSD Intake | Rotofab | 2" LT's | Flex Fuel | 638rwhp / 540rwtq
    2002 Camaro | LSX 427 | CID LS7's | Twin GT5088's | Haltech Nexus R5 | RPM TH400

  6. #6
    Advanced Tuner =fast='s Avatar
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    ^^^ I will have to email you see if you can help me out. Whatever you charge I will pay you I need my truck running good.