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  • #16
    - is taking OUT X% from the base Calibration map.
    Nothing or + in front of X%, is it's adding to the base Calibration map.

    If the VEHICLE is running inconsistently. Then something is wrong with the motor, the EFI system, fuel, or electrical.

    If "I" didn't build the motor then "I" go through a list first:

    1. Timing chain and gears...If part number for camshaft is displayed. Then write it down.
    2. Valve seals.
    3. Intake manifold mounting angle.
    4. Test run motor with carburetor, and 6 PSI fuel regulator...I'm writing down cranking, and idle vacuum, Cylinder pressure ( dry, and wet ). Also. Checking for exhaust leaks.
    5. Replace carburetor with TBI, and remove 6 PSI regulator.
    6. Install O2. Distributor, and other sensors.
    7. Drain, and install fresh gas if vehicle is not daily driven.
    8. Install new spark plugs.
    9. Run, and tune motor.

    I don't trust any ones work but my own, and I don't like doing things over because I was not 100% sure of something.
    At 43,861 MPH Elon Musk now owns the fastest car in this Galaxy

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    • #17
      Engine is under warranty , I cant take it apart to "look" at it . No exhaust leaks , no vacuum leaks .I'm not buying a carb and regulator just to try it , if the intake angle was wrong I would have found a leak when I did the smoke test . I only removed 1 valve spring to inspect , it has the type of seals that are pressed onto the guide . Truck has a completely brand new fuel system from tank to TB with new fuel . 3rd set of new plugs . Tried new MAP,IAC,and O2 . The biggest improvement came after finding the terminal out of the connector on the O2 but the same basic problem still exists .

      I'll say this one more time it didn't have this problem until I tried to "fix" the AFRC , it ran fine with the exception of poor gas mileage no surging , no idle problems etc . I posted my issues here and all this erratic idle , surging and inability to drive didn't start until I made changes suggested here .

      It may sound like I'm blaming you guys for the suggestions but I'm NOT I am simply saying that it did run before without these problems , I've been thinking the same thing about something being wrong with the engine , It is an ATK engine which are known for having issues ( this is the second one ) . There is nothing left to try with the E Street so it looks like the owner will need to make a decision about tearing into the engine .
      Thanks

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      • #18
        ATK is convinced that its an EFI issue . I got a carb and rigged up an external fuel pump fed from a gas can , engine idles fine in park and in gear no surging or variation but it only makes 9" of vacuum . Initial timing is 16* ( they told me to set it at 10* ) I cant drive it due to the fuel system . The carb could have an effect on vacuum as it has holes in the primary throttle blades its more of a "race" carb than a street version

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        • #19
          What kind of spark plugs are you using?
          At 43,861 MPH Elon Musk now owns the fastest car in this Galaxy

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          • #20
            1st and 3rd set were AC Delco R45TS
            2nd set were Autolite 25 I believe . These are the recommendations by Dart

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            • #21
              I’m not sure why the idle quality is so much better with the carb ( it’s off now and it doesn’t have the holes in the throttle plates like I thought ) and I can’t explain the lack of vacuum .

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              • #22
                What will an exhaust leak cause the EFI to do ? I'm going to remove the headers and inspect for leaks to rule that out . I can't find any obvious leaks in the system .

                Pulled headers and inspected ............no leaks
                Last edited by nonracer; 07-20-2020, 05:05 PM.

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                • #23
                  Inspected distributor, coil, advance weights etc ,rockers, re torqued intake , put headers back on , did a compression test since plugs were out ( all pretty consistent ) . Started engine warmed up idle quality is good in park and in gear but AFRC starts out 0 then + single digits , then AFR goes rich and proceeds to -15 to -20

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                  • #24
                    really sounds like you have an exhaust leak . any small leak will cause all the issues your describing .

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                    • #25
                      Confirmed there are no exhaust leaks , confirmed there are no external or internal vacuum leaks . ATK tech is convinced that there is a problem with the FI unit , he thinks there is a leaky injector causing the rich condition . He also thinks the poor vacuum could be caused by a carbon buildup on the valves since its run so rich and fouled 3 sets of plugs already , compression tests indicates 3 cylinders 15lbs lower than the rest . The cause of this might be that cylinders where washed with fuel due to the rich condition ( leaking injectors ) .

                      How do I test for leaky injectors ?

                      Hopefully I can a response soon

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                      • #26
                        Raise the throttle body off the intake manifold ( do this after the motor has ran, and is up to operating temperature ). Then give power to the fuel pump only.
                        If their leaking you will see it.
                        At 43,861 MPH Elon Musk now owns the fastest car in this Galaxy

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                        • #27
                          Raise the throttle body off the intake manifold ( do this after the motor has ran, and is up to operating temperature ). Then give power to the fuel pump only.
                          If their leaking you will see it.

                          Do you mean bypass the ignition and just power up the fuel pump relay ?

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                          • #28
                            Yes. Don't turn on the ignition......you can remove the power wire from the ignition coil to be safer. All you need is the fuel pump to be on, so the injectors are under pressure.

                            When injectors are generally tested ( like at the factory ) their at room temperature. It's best to put some heat into them, so it stimulates real world conditions.
                            At 43,861 MPH Elon Musk now owns the fastest car in this Galaxy

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                            • #29
                              Originally posted by BITE_ME View Post
                              Yes. Don't turn on the ignition......you can remove the power wire from the ignition coil to be safer. All you need is the fuel pump to be on, so the injectors are under pressure.

                              When injectors are generally tested ( like at the factory ) their at room temperature. It's best to put some heat into them, so it stimulates real world conditions.
                              Got it , Thanks

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                              • #30
                                No leaking injectors
                                Thanks for all the help , looks like the engine is coming out and apart .

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