Need help w Vacuum routing - Holley Projection

Discussion in 'Injection Tech' started by rallye, Mar 26, 2018.


  1. rallye

    rallye Farmall Cub

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    Holley Projection 2D on 345 - I've run this for a long time and have never really had this version dialed in... Lately, I've noticed it runs rough at low RPM (intermittenly) and the idle sometimes falls after high RPM under load. Ex: If I drive up a fairly steep grade at 3000rpm and come to a stop sign, the RPM may drop to 400-500...If I turn the key off and re-start it's fine... Also, If I pull over and unplug the (new) PCV valve and plug it back in it runs fine.

    I have replaced, the electronic fuel pump, fuel lines, fuel, TPS, PCV valve and grommet, fast idle sylenoid, checked for vacuum leaks, replaced several vacuum hoses and caps. I spoke to Holley several times and did everything they asked. I'll probably call them with this tomorrow but thought I'd reach out for help here as well.

    Since it seems related to the PCV valve, could I just run a breather off of the PCV valve instead?
    Should I have a hose going into the capped port on the throttle body that says "Manifold vacuum" on the holley diagram?
    Thanks!
    Scott
     

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    Last edited: Mar 26, 2018
  2. Bill USN-1

    Bill USN-1 Moderator Staff Member Moderator

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    Got your msg and was rereading the manual before i replied.
    The port on the back is not connected to manifold vacuum, it is manifold vacuum.
    My first question is:
    Were all the parts you replaced bad, or were you just trouble shooting with your wallet?
    Have you started from the beginning of the installation manual and reset all the initial settings?
    Should be section 19 in the manual.
    The idle speed and TPS need to be set.
    Now, once they are set, here is how the ECM uses the inputs:
    The ECU also powers the fast idle solenoid, which works in direct conjunction with the engine coolant temperature sensor. During cold starts, the fast idle solenoid will remain extended until the engine reaches an operating temperature of 75° F. If the engine temperature is already above 70° F when starting the engine, the fast idle solenoid will remain in the extended position for a factory-set period of time. The amount of time that the fast idle solenoid remains extended is factory set and CAN NOT BE CHANGED by the user. In addition to operating the fast idle solenoid, the signal received from the engine coolant temperature sensor also provides information to the ECU relative to enriching or leaning out the fuel delivery. When the engine is cold, more fuel will be delivered and the fuel delivery is adjusted as the engine warms up. During vehicle operation, the fast idle solenoid is also utilized to allow for a smoother deceleration. During deceleration, the fast idle solenoid is activated for a pre-determined period of time and prevents stalling, as would an idle air control motor. In addition to all of the aforementioned features, a “CLEAR FLOOD” mode has also been programmed into the ECU to aid in vehicle startup should excessive fuel have entered the intake manifold. Should the engine flood during start up, the CLEAR FLOOD mode can be initialized by turning the ignition off, pressing the accelerator all the way to the floor, and cranking the engine until it starts.
     
  3. rallye

    rallye Farmall Cub

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    Thanks Bill, yes - troubleshooting (per Holley tech support) with my wallet.
    Yes I have recalibrated the system many many times, adjusting fuel pressure, TPS, idle screw, ECU main, idle, etc...
    The last recommendation Holley had was the Fast idle sylenoid, and I put that in today and it seemed to help whereas after high rpm under load and coming to a stop it engages more than the old one. However, the new and the old one worked perfectly for cold starts as you mentioned. I have tested coolant temp sensor as well, and is good. I did notice it drop on one occasion though but it picked up shortly after... I'll put some more miles on it this week and maybe I should put the old fast idle sylenoid on and see if it's worse...

    Do you think my vacuum lines are correct, and it's ok to have manifold vacuum capped?
    Thanks Bill!
     
  4. Bill USN-1

    Bill USN-1 Moderator Staff Member Moderator

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    I mentioned the vacuum above.
    The ports are in addition to what you have on the manifold. They are not to be connected to the manifold.
    Your PCV has nothing to do with the system operation.
    You are just changing the rpm when disconnecting and the system is reacting.
    You need to make sure your idle speed is properly set and do not change it.
    The TPS is the last setting you make and if you move the idle, you move the TPS and now it is not properly set.
    Check the injector spray pattern to make sure they are even.
    I use a timing light on the coil wire to shine at them.
    The fast idle solenoid either works or it doesn't. It's not an IAC.
    So you apply voltage and it extends, remove and it goes back.
    If it doesn't work correctly when connected to the system, then either the wiring is bad or your ECM is bad. Not the fast idle solenoid.
    You are spending money on a system that wasn't even that good when new.
    People sell them all the time......for a reason. I have given away several of them after I made the mistake of trying to use one back in my early days.
    They are only slightly better then a carb due to the pressurized fuel for off road.
    Only you can decide how much time and money you want to put into it.
    It doesn't sound like Holley did much more than convince you to buy more parts.
     
  5. rallye

    rallye Farmall Cub

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    Thanks Bill! There's only one guy left at Holley that knows these systems... He just told me to try a breather / filter instead of the PCV valve.
    Right now, I have the flame arrestor going into the air filter. I'll try to find a small filter to use as a breather instead of the PCV valve and see what happens. Tired of messing with this thing...
    Thanks for your time Bill!
     
  6. Bill USN-1

    Bill USN-1 Moderator Staff Member Moderator

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    You never remove the PCV valve.
    You will blow oil out everywhere.
    You are free to listen to anyone you want.
     
  7. winchested

    winchested High Wheeler

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    A flame arrestor and pcv are not the same. Flame arrestor is filled with steel wool. Pcv is a check valve.
     
  8. rallye

    rallye Farmall Cub

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    @winchested - Right, flame arrestor has been cleaned and has a hose going into air filter housing as shown in picture. Pcv valve is new going to throttle body port per holley instructions, never said they were the same...thanks for your time though.

    Thanks Bill, yeah I've been reading all about that for the last 15 min...Hmmm, the saga continues...
     
  9. Dana Strong

    Dana Strong Y-Block King

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    Assuming he actually meant that, it proves he doesn't know how engines work. The PCV regulates how much air (and fumes) are allowed to enter the intake. Removing the valve is akin to having five guards counting, measuring, checking and photographing everyone coming through the courthouse front door, while the back door is wide open and unguarded.
     
  10. Bill USN-1

    Bill USN-1 Moderator Staff Member Moderator

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    There is no saga.
    You test each part to see if it is in spec and operational.
    If it is , you move on.
    If the parts are good then you set all initial settings correctly.
    If it does not work correctly then you know what the problem is and your just choosing to ignore the obvious.
    You can say you checked everything and replaced everything and set up everything according to the instructions and not know what the problem is.
    What part have you not tested?
    This should take about 2 millisec for you.
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    yes, the ECM!
    This assumes you have really done all the above.
    But your welcome to keep sending Holley more money!
     
  11. rallye

    rallye Farmall Cub

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    Running like a champ!
    Must have been the fast idle solenoid. The old one must have been tired. After I replaced it, it still wasnt running great. Then I noticed the pink wire was loose on the neg side of the battery... (grounding the pink wire puts the ECU in small block mode) It must have been going back and forth. However, I know this only became loose recently when I charged the battery. After I tightened it and took another test drive - Perfect! Idle is clean and does not fluctuate. Also, it does not fall after being under load at high rpm when you come to a stop. Thanks for the tips Bill.
     
  12. Bill USN-1

    Bill USN-1 Moderator Staff Member Moderator

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    Grounds are the most important thing to electronics.
    Glad it's doing again.
     
  13. greaganing

    greaganing Farmall Cub

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    Any chance you could take a few pics of what you did to get it right so I can compare? Vacuum tubes that is?
     
  14. rallye

    rallye Farmall Cub

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    @greaganing - I had it right, I think my ecu was bad like Bill said above. I had the projection running great after this and then it would intermittenly drop idle...I have since upgraded to the Holley 4 injector Sniper EFI. It's great and was an easy upgrade since my fuel lines, pump and filters were already there and up to spec.
     

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