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68-72 chevelle elcamino pf4 install

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  • 68-72 chevelle elcamino pf4 install

    7-13-20

    This thing really is a great system even with the progressive linkage.

    however,


    Since the PF4 install. It has had a slight stumble just off idle weather you are "driveway" tuning or road tuning that just wouldn't go away. I figured it was due to not having enough road time and the fact that the ECU has to see greater than 50% TPS to add the pump shot from what i understand.

    Well come to find out the fuel pressure when being viewed on the smart device was reading 44 PSI but the gauge I installed on the adjustable regulator was only saying 34ish PSI at idle with vacuum disconnected and hose plugged. SO after resetting the fuel pressure to 44PSI using the gauge it runs and seems to have lost the stumble. throttle response seems crisper as well. Its also worth noting that I did NOT clear the self learn like I probably should have to quicken the learn time.

    That said,
    it was taking out about 12-15% short term fuel for a while but is back to 0-5%.

    Next step,

    Next project will be to install the Lokar throttle cable and fab a "pan" for the air filter assembly to the CI hood.

    The current GM q-jet cable works and seems to function fine but visually looks like it is binding. The stop is all the way back and it looks and feels like its working but it will never get back to 0% TPS consistently. It stays at 1-2% after start up and the first pedal movement. Ill wager its because of a possible binding issue of the OEM cable internally that cant be seen.

    Isnt it a true statement that its critical that the ECU have a full 10-12 sec delay between "key on" cycles to reset the TPS to 0% or it monkies with things and starting can be problematic. It was in my case anyway and that with EFI you must have near perfect TPS or it can wreak havoc between the various "modes" of operation. Like from idle to cruise, cruise to WO mode, etc

    this is the cable Im using. Im not sure the clevis retention system will work at/with the OEM pedal without looking goofy but we will see.

    https://www.speedwaymotors.com/Lokar...ble,97761.html

  • #2
    Good info thanks for sharing. Guess i need to check fuel pressure.

    Comment


    • #3
      Remove the clevis from the cable and slide the cable through the OEM plastic retainer on your pedal , the "ball" that is crimped on the cable will hold it. You might need a small #6 washer on the cable if the
      "ball" is too small .

      Comment


      • #4
        With key on TPS sets to 0.
        Key off IAC parks.
        At 43,861 MPH Elon Musk now owns the fastest car in this Galaxy

        Comment


        • #5
          Originally posted by BITE_ME View Post
          With key on TPS sets to 0.
          Key off IAC parks.
          why is it then after the first pedal movement of any kind it will never return to zero. It always stays at 2% and occasionally will drop to 1% if I "blip" the throttle.

          Comment


          • #6
            Originally posted by nonracer View Post
            Remove the clevis from the cable and slide the cable through the OEM plastic retainer on your pedal , the "ball" that is crimped on the cable will hold it. You might need a small #6 washer on the cable if the
            "ball" is too small .
            yep i discovered that yesterday when it arrived via UPS. Seems like it is a no brainer install.

            Comment


            • #7
              Originally posted by marc s View Post

              why is it then after the first pedal movement of any kind it will never return to zero. It always stays at 2% and occasionally will drop to 1% if I "blip" the throttle.
              If there is no binding issues. Then the TPS should be replaced.

              Originally posted by 2700 Cast View Post
              • Standard Products # TH42
              At 43,861 MPH Elon Musk now owns the fastest car in this Galaxy

              Comment


              • #8
                Originally posted by BITE_ME View Post

                If there is no binding issues. Then the TPS should be replaced.

                Ill start with the cable and then see where we land on TPS signal.

                Comment


                • #9
                  Make sure you test the tps first by ignition on, engine off, work the throttle with your foot and see if it comes back to zero. Even with a new tps, mine still comes down to 1% at times, don't know what the issue is. Not causing any drivability issues, I just ignore it.

                  Comment

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