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  • Chevy HT383 , more cold start problems, engine dies

    Edelbrock kit #357800
    Chevy HT383 Vortec crate engine, brand new
    Duration-196-206 Lift .450" , 21" Vacuum at idle when engine is warmed up
    340 advertised HP
    ACDelco R44LTS Spark Plugs .040" Gap , Pertronics Flame Thrower #40111 Coil Chevrolet Performance spiral core plug wires
    18* Idle timing, 32* total @ 3000 RPM , advance starts at 1200 RPM
    IAC% is at around 12when warmed up to operating temperature
    43-44 PSI fuel pressure, Edelbrock fuel sump, PWM turned on, 29Lb injectors
    MAP # 5017
    Video https://youtu.be/Boofzq9ER1k
    I finally got this thing to cold start somewhat tolerable. But by the time I back out of my driveway and shift from reverse into drive the engine dies. When I start it cold and shift immediately into gear it doesn't die. After 30 seconds the closed loop light comes on and the computer starts leaning it out, then it dies when shifted. When the engine reaches 165* and goes into closed loop self learning mode it shifts and runs perfect. If I add fuel to the cold start modifier it does not help. What really bothers me about this system is I can not wrap my head around how the cold start section of the map works. What is the point of having modifiers if the closed loop is just going to remove the fuel you added? Please watch the whole video before you start sending comments. Yes I did try adding more idle timing and it did not help. If you notice in the video the spark advance jumps to 41, the IAC goes to 78, the inject goes to 12.4 the instant I shift it into gear. I have searched the forum and still have not been able to find an explanation of how the cold start section of the map works that matches the experience I have had with it. Thanks in advance for help!

  • #2
    have you called the techline?

    I wonder if you should try a leaner map like 5006. You're AFR is super rich when the 02 sensor comes online and your Short Fuel trim maxes out at -30. It's trying to remove fuel but then on top of that then you keep ADDING more fuel with the cold enrichment. Somethings not right.

    Comment


    • #3
      Originally posted by CMerchant View Post
      have you called the techline?

      I wonder if you should try a leaner map like 5006. You're AFR is super rich when the 02 sensor comes online and your Short Fuel trim maxes out at -30. It's trying to remove fuel but then on top of that then you keep ADDING more fuel with the cold enrichment. Somethings not right.
      If you notice, I shift it into gear before the closed loop light comes on and it does not die . In fact it pulls so hard that I have to really clamp down on the brakes to keep the truck from moving . If it is too rich before it goes into closed loop and removes fuel, why does it run perfect when put in gear and not even try to die. It only dies after going into closed loop.

      Comment


      • #4
        How miles have you driven with the PF4 kit installed?
        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


        • #5
          Originally posted by 2700 Cast View Post
          How miles have you driven with the PF4 kit installed?
          About 1000 miles. Startup has been terrible, but when it is 165* and in closed loop self learn it runs extremely nice, and working with Tommy in the tech department I have been able to get the startup much better , but it still misses a lot on startup and has the problem shown in the video.

          Comment


          • #6
            Watching the video & it dies, is it doing this when in Park ?

            or only when shifting out of Park into rev/drive ?
            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


            • #7
              Originally posted by 2700 Cast View Post
              Watching the video & it dies, is it doing this when in Park ?

              or only when shifting out of Park into rev/drive ?
              I am shifting from park to reverse in the video when it dies .

              Comment


              • #8
                Cold start fuel adds/subtracts fuel to the Calibration map, only when cold.....it doesn't care what the AF ratio is......it just adds/subtracts fuel.

                Minimum learn RPM is 1200 I believe......its adjustable.

                It's basically pointless for a EFI system to Learn a idle setting.....only altitude changes, and that's covered by a vacuum referenced fuel regulator.

                Yes there are 2 different "Normal" idle's.....ingear, and out of gear.......tune these first.

                The Cold Start Idle is always tuned last.



                Jackrabbiting a cold motor is not a wise thing to do.

                The system will naturally raise the idle speed to warm it up faster.....it can't do this if your moving the gas pedal around, and putting a load on the motor.....you just lost all the cold start fuel settings. So now it's going to rely on what the AFR setpoint is.

                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


                • #9
                  Originally posted by BITE_ME View Post
                  Cold start fuel adds/subtracts fuel to the Calibration map, only when cold.....it doesn't care what the AF ratio is......it just adds/subtracts fuel.

                  Minimum learn RPM is 1200 I believe......its adjustable.

                  It's basically pointless for a EFI system to Learn a idle setting.....only altitude changes, and that's covered by a vacuum referenced fuel regulator.

                  Yes there are 2 different "Normal" idle's.....ingear, and out of gear.......tune these first.

                  The Cold Start Idle is always tuned last.



                  Jackrabbiting a cold motor is not a wise thing to do.

                  The system will naturally raise the idle speed to warm it up faster.....it can't do this if your moving the gas pedal around, and putting a load on the motor.....you just lost all the cold start fuel settings. So now it's going to rely on what the AFR setpoint is.
                  And how do I tune these 2 idles in cold start?

                  Comment


                  • #10
                    Originally posted by wims58ej View Post

                    And how do I tune these 2 idles in cold start?
                    IN GEAR:
                    The motor is cold, and has a load on it ( automatic in gear= foot on brake pedal. Manual in gear= Dyno { poor man's dyno is blocked front wheels on pavement, rear wheels on constantly water sprayed surface }.
                    In the App:
                    Home Screen.
                    Advanced Tuning.
                    On/Off Options.
                    Make "Idle Control" turn RED..........if motor runs better when it's GREEN. Then change it back.

                    If the above doesn't work better.

                    Let the motor cool down for 1/2 hour.

                    Change the Idle Air Fuel Ratio to be richer ( this will help replace the extra needed fuel the O2 sensor takes out, when it comes on line ) in 0.20 steps, till you have a usable, smoothest idle.

                    ​​​​​​

                    OUT OF GEAR:
                    Do the above first ( In Gear ).
                    If idle is not smooth. Then adjust timing.....you will most likely need to drop it down 2 numbers.


                    You can try the above to see what works best.
                    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


                    • #11
                      A month later and still I have made no progress with this system. It still runs extremely rough on cold start and stalls when shifted into gear when cold no matter where I set the cold start and crank fuel. Runs perfect after warm up in every way. These are the things I have done so far. Tried map 5006 and 5017, no difference on initial cold start mis-fire no matter where I set the crank and cold start fuel modifiers. Edelbrock tech told me to use map 5017, route the wiring further away from the ignition wires, so I rerouted all wiring as far away from ignition as possible and even wrapped the wiring in aluminum foil and tape over that. Grounded the aluminum foil on both ends. Confirmed TDC mark on harmonic balancer a with a piston stop [this is a brand new GM crate engine]. Checked the short tooth, and #1 terminal alignment in distributor at least 4 times so far. Checked timing too many times to count. Borrowed a timing light to confirm mine is reading correctly. Re-checked valve lash. Did compression test. Compression is between 155 and 168 PSI. Very good for a new engine. I removed the IAC and checked for obstructions in the passages. Everything looked perfect. I have installed 3 new sets of spark plugs, because they turn very black from the cold start misfiring. I have tried a new oxygen sensor. No help. I even bought a new computer because I'm so sick of working on this piece of crap. That was $550. It made no difference. I set up a camera to record the timing on cold start. I transferred the timing marks to the bottom of the harmonic balancer with a temporary pointer to make it easy to film, and to point the timing light at the balancer. I uploaded the video to youtube. I know the shutter of the camera sometimes kinda screws up the image of the timing light flash, but it worked. https://www.youtube.com/watch?v=4Byx3I8NICo When I watch the video frame by frame on my computer from the original SD card, the first time I can see the #1 plug fire it is at almost 50* BTDC, 2nd, 3rd, 4th, 5th sparks 47*, 6th, 7th sparks 35*, 8th-11th spark 32*, around the 12th spark it stabilizes around 26* to 28* BTDC. I know that the #1 fires once every other revolution, so I am missing a lot of information. The tablet is showing 23* when the timing light is showing 26* on the harmonic balancer, but 3*seems close enough to ignore that. Why is it starting so advanced? This can't be good. Or is this what it's supposed to do? Does this mean the IAC is not opening up on startup and the timing advance is trying to keep the engine running? IAC is set at 12% when engine is at operating temp. Also, the engine begins to smooth out after about 25 seconds after cold start. But it misfires, blows black smoke out tailpipe, and sounds terrible on cold start. The second half of the video I opened up the throttle blades 1 full extra turn in. Let the engine cool back down and cold started it again. The second video is a little clearer. Watching frame by frame is see 12*, 23*, 42*, 32*, 27*, 25*, 23*, stabilizes at 23*. Still sounds like it is missing a bit for a couple of seconds, but not as bad. The other 2 videos I uploaded about this issue are still on my youtube channel, and show the extreme mis-firing. https://www.youtube.com/watch?v=D5rci9tYfAQ&t=1s At 0:28 minutes, notice the timing on the tablet. This is an initial cold start.
                      ANOTHER NEW DEVELOPMENT YESTERDAY. I did not realize that I could turn on the ignition, open the edelbrock app and connect to computer, lock the ignition at 12* [set base timing]. Then when I start the engine it will start with the timing locked at 12* BTDC. When I did this with the engine cold, It fired off instantly and ran perfect. The IAC was loud because it needed more air with the timing locked, but I started and idled like a brand new Toyota or whatever. Smooth as silk. It shifts into gear without dying, and just sounds perfect. Then I unlocked the timing and changed nothing else. Waited till it cooled off and restarted. It went right back to misfiring, black smoke and black water shooting out of the tailpipe. I also bought a new IAC this weekend and tried it. It made no difference. As before after a few minutes warm up, without the timing locked, the engine smoothes out and runs perfect. Why is this thing forcing the timing to extreme advance on cold startup? I believe it is advancing the timing so far it is jumping to the next cylinders distributor terminal which causes it to start loping and misfiring. It is not the computer, because I tried a new one and no change.

                      Comment


                      • #12
                        WIMS58ej Send me an email with your Contact phone number. [email protected]

                        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


                        • #13
                          I will throw something out there and you can do with it what you will. I believe that you do not have the vacuum line hooked up to the sump regulator based on the fuel pressure shown on your video. The fuel maps are set up based on fuel pressure being adjusted for high vacuum conditions (lowers fuel outlet pressure) and in doing so the amount of fuel the injector puts into a cylinder for a given map point. Looking at your video, the O2 sensor shows 10.0 prior to the system going into closed loop, however when it does go into closed loop it is pulling a very large amount of fuel. I saw -30 for short term fuel trim. You may find that when you vacuum reference your fuel sump that the reduced fuel injected before closed loop is not as excessive and may ease the problem that you are experiencing. I would do that with fuel modifiers at 0 and then adjust from there. Just my 2 cents.

                          Comment


                          • #14
                            I agree with ddsmith.
                            The video was edited kind of fast for my taste ( the last one ).
                            But I kept a eye on the "Inj Duty"...the part of the video where you put it in gear;; Looks like the Calibration map is to rich ( fuel pump pressure to high ), then you removed fuel ( inj duty whent down ), then when you put it in gear ( injector duty jumped way up ).

                            You should hookup the regulator to the throttle body to bring the fuel pressure down.
                            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

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