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  • Squealing during Acceleration

    Anyone else get a squealing on moderate/hard acceleration with the PF4 system? happened instantaneously with my PF4 installation (IE wasnt there with the carb) and I even replaced my serpentine belt with only 1K miles on it to test. No change.

  • #2
    Rear tires?

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    • #3
      Originally posted by CorkyE View Post
      Rear tires?
      haha i wish - definitely coming from the engine bay

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      • #4
        Remove ( for testing only ) drive belts & see if noise goes away----
        Don't get too caught up in the numbers.
        Just give the Engine what it wants &
        Let the numbers be what they are.

        Jim McFarland....

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        • #5
          You generally only get 4 noises from a EFI system:

          1. Fuel pump noise.
          2. Not using a air silencer device on the throttle body.....need to use factory type air cleaner housing.
          3. Injector clatter......from putting the fuel regulator to far away from them....it acts like a damper.
          4. IAC whistling, or air rushing sound......a piece of carbon flake is in it's chamber, or it's not set-up right.

          ​​​​​
          In my neighborhood, if you open your hood to check your oil, and the vehicle still runs after you close it.......Then your labeled the Neighborhood Mechanic.
          https://forums.edelbrock.com/filedat...?photoid=42773

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          • #6
            Originally posted by 2700 Cast View Post
            Remove ( for testing only ) drive belts & see if noise goes away----
            sorry if this sounds dumb but you're saying remove the serpentine belt and go for a drive?

            Comment


            • #7
              Originally posted by BITE_ME View Post
              You generally only get 4 noises from a EFI system:

              1. Fuel pump noise.
              2. Not using a air silencer device on the throttle body.....need to use factory type air cleaner housing.
              3. Injector clatter......from putting the fuel regulator to far away from them....it acts like a damper.
              4. IAC whistling, or air rushing sound......a piece of carbon flake is in it's chamber, or it's not set-up right.

              ​​​​​
              -Fuel pump is in-tank at rear of truck. doubt thats it.

              -silencer device? I'm running the K&N air filter with the filter element top/lid.

              -fuel regulator is the edelbrock 58 psi unit on the end of the rail. doesnt sound like "clatter" more screaching/squealing

              -was wondering if it was IAC but would it come on/open under acceleration way above idle? My IAC *may* not be set up perfect as I have a dying when put in gear issue that only happens below 105* that cold enrichment cant seem to solve. When hot my IAC is 0% at idle and my idle is set for 825 rpm in the tablet. Not sure if any of this is related to the sound im hearing.

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              • #8
                Originally posted by CMerchant View Post

                sorry if this sounds dumb but you're saying remove the serpentine belt and go for a drive?
                Try to duplicate noise by performing a Stall test ( aka Torque-Brake ) in the driveway before engine gets too hot -since water pump is not turning. Testing Purposes Only---Take Precautions/at your own -risk/where it is safe & clear..
                Note: if not comfortable have a Certified Technician assist & perform.
                Don't get too caught up in the numbers.
                Just give the Engine what it wants &
                Let the numbers be what they are.

                Jim McFarland....

                Comment


                • #9
                  Originally posted by CMerchant View Post
                  When hot my IAC is 0% at idle and my idle is set for 825 rpm in the tablet. Not sure if any of this is related to the sound im hearing.
                  IAC should never be at Zero at idle speed.....hence why you have some issues.
                  In my neighborhood, if you open your hood to check your oil, and the vehicle still runs after you close it.......Then your labeled the Neighborhood Mechanic.
                  https://forums.edelbrock.com/filedat...?photoid=42773

                  Comment


                  • #10
                    Originally posted by 2700 Cast View Post

                    Try to duplicate noise by performing a Stall test ( aka Torque-Brake ) in the driveway before engine gets too hot -since water pump is not turning. Testing Purposes Only---Take Precautions/at your own -risk/where it is safe & clear..
                    Note: if not comfortable have a Certified Technician assist & perform.
                    I performed the test w/o the serp. belt on and I still have the squeal sound. It seems to come in around the same throttle point/rpm point consistently.

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                    • #11
                      Could be a vacuum leak. I had an intake gasket go bad on an older engine, made a small whistling sound.

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                      • #12
                        Originally posted by CMerchant View Post

                        I performed the test w/o the serp. belt on and I still have the squeal sound. It seems to come in around the same throttle point/rpm point consistently.
                        You need a bigger stereo system........or the opposite....earplugs.


                        Put the belts back on.
                        Take the air cleaner off.
                        If the sound is louder. Then it's the IAC.
                        In my neighborhood, if you open your hood to check your oil, and the vehicle still runs after you close it.......Then your labeled the Neighborhood Mechanic.
                        https://forums.edelbrock.com/filedat...?photoid=42773

                        Comment


                        • #13
                          Originally posted by BITE_ME View Post

                          You need a bigger stereo system........or the opposite....earplugs.


                          Put the belts back on.
                          Take the air cleaner off.
                          If the sound is louder. Then it's the IAC.
                          Why would the IAC be opening above 1500 RPM while on the throttle/accelerating?

                          Doing some googling of "EFI screeching during acceleration" there's a bunch of Holley guys with the same issue and they put a small 1/4-1/2" 4 hole spacer under their throttle bodies and the sound went away. While I understand theyre talking about a different product it's the same issue: https://forums.holley.com/showthread.php?20273-Sniper-loud-whistle-hiss-normal

                          Also - I'll note that i've seen the instructions several times on here to set the idle in the tablet at say 700 then set the idle to 750 with the throttle screw and that results in a 0% IAC during idle. in any event I will try to reduce the throttle opening in order to achieve the 5-15% IAC number per the instructions and see if that helps.

                          Otherwise is there any issue in trying a throttle body spacer?
                          Last edited by CMerchant; 06-10-2021, 06:36 PM.

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                          • #14
                            Originally posted by CMerchant View Post
                            Otherwise is there any issue in trying a throttle body spacer?
                            I have never seen any one with a "Complete" Edelbrock EFI System needing to band-aid their system.............1 or 2 E-Street folks felt their Throttle Body EFI System worked better with some type of spacer......one was actually made to heat up the incoming air.

                            Holley's system that mimics Edelbrocks Pro-Flo would be a better comparison ( I believe Holley's cost over 4 grand now, and you have to pull all the parts out of small boxes, and assemble it your self...IKEA EFI ), then their Throttle Body System installed on a random Intake manifold.

                            In my neighborhood, if you open your hood to check your oil, and the vehicle still runs after you close it.......Then your labeled the Neighborhood Mechanic.
                            https://forums.edelbrock.com/filedat...?photoid=42773

                            Comment


                            • #15
                              2700Cast - anything to add? is my IAC just not set properly and that's it?

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