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Hard to start 454

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  • Hard to start 454

    I have a starting issue with my Edelbrock e-street 2. I am using the Edelbrock ingition control kit. Base timing set to 12 degrees. I have to cycle the key about 15 to 20 times before it will even try to fire. It takes several trys before it starts. Then went it does start it runs like crap. It back fires out the intake at steady cruise speeds. I can't even drive the truck it back fires repeatedly. When I first installed the system it would start right away, ran good and would occasionally back fire out the intake when under a heavy load. But the back firing got worse then it started dieing and got hard and harder to start.

    My 454 is a fresh build with 2800 miles on it. It has procomp 320 heads with a comp cams 252 hydraulic roller cam. Rpm air gap. Motor is 8:1 on the compression. Vacuum at idle is 17-18 idles great just hard to start and constantly back fires.

  • #2
    Sounds like it is running on the wrong map. Or there's not enough fuel pressure. Do to the hard starting. It looks more like a fuel problem.
    What is the fuel pressure at the throttle body?
    What is the type/parts used in the fuel system?
    <-- Do not click the BLUE boxes. They are a trap. You will be sucked into the Matrix, and never leave. The project in your garage will never be finished. You have been warned.

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    • #3
      It has map 36020V21 installed. My fuel pressure is 57 to 63 psi at idle. I used a FiTech external fuel pump kit and used a Edelbrock fuel pressure regulator to regulate the pressure to 60 psi.

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      • #4
        PSI is 58 for the E-Street. That map is ok.
        My gut says you might have a plugged injector.
        When you fist turn the key on. The injectors will spray. I would make sure thay all spray.
        Or there might be a bad connection to one.
        <-- Do not click the BLUE boxes. They are a trap. You will be sucked into the Matrix, and never leave. The project in your garage will never be finished. You have been warned.

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        • #5
          Almost forgot:
          You should see an abnormal high number in the AFC table, and the duty cycle of the injectors should be very high to......the system will try to add fuel do to a clogged/unconnected injector, and the system will try to open the injectors for a longer time ( percentage ) too.

          How could the injectors get plugged, even with use of a fuel filter?
          Some formulas of fuel have been eating fuel lines. Some people are switching to a PTF type.
          For me. I use a AN filter mounted on the engine, and bend/flare a hard line from this filter to the carburetor/fuel injectors....if you mount the filter solidly to the engine, then you can use a hard line ( metal ).
          <-- Do not click the BLUE boxes. They are a trap. You will be sucked into the Matrix, and never leave. The project in your garage will never be finished. You have been warned.

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          • #6
            What is the vacuum reading on the tablet? I have seen backfires damage the MAP sensor. It should read -0.1" Key On, Engine Off. If it is a lot different than that, it could be your issue. Have you tried adjusting Cranking Fuel?

            You are on the correct map. Try reloading the map and firmware in case something got corrupted. You should have your idle spark set to 18 degrees on the tablet.
            Last edited by Steve M; 01-11-2018, 12:29 PM.

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            • #7
              Key on vacuum 0.2 once started afr fluctuates from 14.6 to 13.1 target is 13.8 afr correction -23. injector duty is between 6 to 8. I have crank fuel maxed out at 20

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              • #8
                Something is not right here. The vacuum reading is fine. If the AFR Correction is -23, that means the ECU is reducing the amount of fuel by 23%, which is a lot. What is the AFR Correction when it is hot at idle and 1,800 RPM?

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                • #9
                  After letting it warm up to 180 it went the opposite on afr correction correcting 10 to 20% and at 1800rpm 6 to 15% correction

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                  • #10
                    MAP sensor lets the system know what kind of load is on the motor.
                    IAC will regulate the speed of the motor. If misbehaving, it will affect the MAP sensor readings.

                    I would double check that both have nice straight pins in their connectors.
                    <-- Do not click the BLUE boxes. They are a trap. You will be sucked into the Matrix, and never leave. The project in your garage will never be finished. You have been warned.

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                    • #11
                      That sounds like an exhaust leak. Normally that is what we find when the correction is around 20% at idle and goes down as the RPM goes up. I would take a hard look at the exhaust manifold gasket. Any leak upstream of the O2 sensor can cause problems. The best way to find a leak is using a smoke machine for evaporative emissions testing. Tape off one tailpipe and put the smoke in opposite side. You have to do it indoors without any wind.

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                      • #12
                        A spray bottle with soap/water and shop vacuum, and duct tape works good too. You don't even run the motor for the test.
                        <-- Do not click the BLUE boxes. They are a trap. You will be sucked into the Matrix, and never leave. The project in your garage will never be finished. You have been warned.

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                        • #13
                          After working on this thing for weeks it no longer starts. I don't have any exhaust leaks. Everything is new on this truck it only has 2800 miles since the frame off was completed. I am fixing to give up and go back to a carburetor.

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