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  1. #1
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    Default Frustrating fuel pressure issue. Please help!

    Iíve been building this project over the course of too many years now and finally got my motor started the other day. Itís a 308 to 383 in a 242gt Volvo. Anyway it was a fresh build so mucked around for a bit getting oil pressure right. Iím also running a Holley ultra 750 with a black pump and 1/2Ē lines. No return. I have a Holley pressure reg going to a fuel log which has a pressure gauge on it.

    Before I started the engine I adjusted it so the fuel pressure was reading 8psi. after the first time I started the engine it now climbs to 16psi. Doesnít mater if the Set screw is fully up or down it wonít change. I rigged up another gauge and same reading on that. Thinking there may be a problem with the reg I took that apart and it all seemed good.
    Now even when I turn the ignition on the fuel pressure creeps up to 16psi.

    The oil smells very fuely and feels like its choking on fuel when itís running.

    I canít think what it could be because. My reg is a 4.5-9psi standard not bypass. Holley even state the max pressure of the black pump is 14psi and Iím getting 16psi wtf?!?

  2. #2
    casual poster Lacksballs's Avatar
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    Check that you have the regulator connected correctly, check the ports as you may have them reversed.

  3. #3
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    Hi,

    Yeah that was the first thing I checked. In from pump and out to fuel log.

    Just weird that it seemed to sit on 8psi when I first adjusted it then it went haywire after I started the motor

  4. #4
    casual poster Willie's Avatar
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    Is the in tank pump still connected?

  5. #5
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    HI
    Connection checked tick
    Correct regulator is it for carby application and standard dead head style ????
    Each regulator has a specific flow rate and pressure of supply IE Is the pump to big for the regulator ???

    Is there nothing physical in the lines of poor quality bends , kinks ,restrictive filter etc etc

  6. #6
    254RWHP boat anchor EVL253's Avatar
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    not sure about the black pump but i know the bigger pumps like the HP150 come with a lot bigger reg than the old holley 803 style. i do have one of them kicking around gathering dust.

    honestly if it was me i would change the plumbing and reg & make it a bypass type system. return line ideally is bigger than feed line so the reg is the restriction.

    those deadhead holley regs if you have a look inside the orifice is small and got a big pump straining to pump fuel through a orifice thats around 1/4 inch...
    11 second E85 bottle fed boat anchor

  7. #7
    Part of the furniture monaroman76's Avatar
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    Quote Originally Posted by shitavl View Post
    Iíve been building this project over the course of too many years now and finally got my motor started the other day. Itís a 308 to 383 in a 242gt Volvo. Anyway it was a fresh build so mucked around for a bit getting oil pressure right. Iím also running a Holley ultra 750 with a black pump and 1/2Ē lines. No return. I have a Holley pressure reg going to a fuel log which has a pressure gauge on it.

    Before I started the engine I adjusted it so the fuel pressure was reading 8psi. after the first time I started the engine it now climbs to 16psi. Doesnít mater if the Set screw is fully up or down it wonít change. I rigged up another gauge and same reading on that. Thinking there may be a problem with the reg I took that apart and it all seemed good.
    Now even when I turn the ignition on the fuel pressure creeps up to 16psi.

    The oil smells very fuely and feels like its choking on fuel when itís running.

    I canít think what it could be because. My reg is a 4.5-9psi standard not bypass. Holley even state the max pressure of the black pump is 14psi and Iím getting 16psi wtf?!?
    Replace your regulator.
    Aside from affecting your float levels, your fuel pressure has nothing to do with whether it is running rich or lean.

  8. #8
    Do you ever leave?
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    Is it a deadhead reg or a return reg.

    As EVL253 suggested, going to a return system as many benefits.

    Likely it smells fuely as the fuel pressure is overpowering the floats and dribbling raw fuel into your engine.

    It could be something as simple as junk in the regulator. Perhaps take it apart and have a look-see. *edit - sorry - I see you have already taken the reg apart. I assume therefore you have identified that it is indeed a deadhead reg?

    The ports on each reg are labelled accordingly:-

    https://www.bing.com/images/search?v...jaxhist=0&vt=0
    Last edited by Bill355; 12-06-2019 at 03:48 PM.

  9. #9
    Do you ever leave? EH179's Avatar
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    I bet you're using a 12-803 regulator on this? If so, it will be the problem.

    A Holley black needs a 12-704 to operate correctly.

  10. #10
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    It is a 12-803 and I have a Holley black fuel pump so Iím guessing thatís the problem because virtually everything else is new -8 hose and 1/2Ē hard lines with speedflow connections.

    Iíll check out the 12-704. Thanks for the advice.

  11. #11
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    This was a clear case of R.T.F.M. After digging it out I can confirm the 12-704 is what is recommended by Holley for use with the black pump.

  12. #12
    254RWHP boat anchor EVL253's Avatar
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    i have one of those 12-704 regs doing nothing if your after one. pm me
    11 second E85 bottle fed boat anchor

  13. #13
    casual poster kiwiholdenman's Avatar
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    As a side note when having probs with regs undo the four screws on top and remove said top
    and closely inspect the steel ball bearing as have seen said bearings badly pitted with rust,even new ones
    so consequently the reg is rooted from the get go as it will bleed pressure regardless of settings,
    the other thing is if it seems adjustments run out is to undo said screws to reset it,if that makes sense.

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