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Thread: He is 40 psi enough fuel pressure

  1. #1
    Tuner
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    He is 40 psi enough fuel pressure

    I?ve got an LS swapped 99 suburban. I noticed when I first started it up it was running lean. I checked fuel pressure at the rail And I?m only running 40 psi at idle. I scaled my injectors and now it?s running close to 14. Will 40 pounds be enough pressure or do I need to look at upgrading the pump?

  2. #2
    Tuning Addict 5FDP's Avatar
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    May 2012
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    Rogers, MN
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    Upgrade the pump.

    Just about all injectors are rated at 43.5 or 58psi. You will want to run 58psi if they are small injectors because 43.5psi will lower the flow rate rating and you will run out of injector room much sooner.
    2016 Silverado CCSB 5.3/6L80e, not as slow but still heavy.

    If you don't post your tune and logs when you have questions you aren't helping yourself.

  3. #3
    Tuner
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    They are 30lbs at 58psi so based off this calculator ( https://www.deatschwerks.com/fuel-ca...ure-calculator) I scaled my injector flow to 25 which made it run correctly. Just don?t have the funds to replace the pump right now. Not to mention dropping that 40 gallon tank that?s 1/2 full.

  4. #4
    Tuning Addict blindsquirrel's Avatar
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    Apr 2017
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    Meridian MS
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    Yes, it'll be much cheaper to replace the pump after it dies and leaves you stranded and then you have to pay to have it towed, too. Park it until you can replace the pump (and the filter that's now plugged with the brush material from the dying pump). The filter is likely restricted but that's a symptom of the dying pump, not the cause.