current ramping injectors with the vantage pro

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  • racingdave
    Member
    • Jul 2009
    • 50

    current ramping injectors with the vantage pro

    Just bought a vp and was checking out injector current ramp test on a 92 plymouth voyager van 3.3. VP told me that i could see 135 or 246 so i chose the front three cylinders i could ony see one injector at a time i need to see them all.I messed around with the screen adjustments and was able to mess with my pattern and make it larger and smaller and i actually got a pattern of three only by raising the idle to about 1500.I unpluged an injector and saw no differance in the pattern so i must have the settings wrong how do i adjust the screen to see all the injectors?If iam doing a test on 4 6 or 8 cylinder engine should not i see all the injectors?
  • Crusty
    Senior Member
    • Dec 2007
    • 2450

    #2
    Originally posted by racingdave
    Just bought a vp and was checking out injector current ramp test on a 92 plymouth voyager van 3.3. VP told me that i could see 135 or 246 so i chose the front three cylinders i could ony see one injector at a time i need to see them all.I messed around with the screen adjustments and was able to mess with my pattern and make it larger and smaller and i actually got a pattern of three only by raising the idle to about 1500.I unpluged an injector and saw no differance in the pattern so i must have the settings wrong how do i adjust the screen to see all the injectors?If iam doing a test on 4 6 or 8 cylinder engine should not i see all the injectors?
    Most injectors are controlled by the ECM/PCM turning on the ground side of the injector. In order to see the current for any batch of injectors you have to hook the pickup around a common wire, which would be the Ign-+ voltage wire that feeds the injectors.
    On this Dodge, the VP is telling us that 3 injectors have a common B+ wire and by adjusting the time base you can either see all 3 on that common feed or just one.
    With a common B+ feed for 1,3 & 5, you can only see those three. With a different feed for 2, 4 & 6, you can only see those three.
    My GM product has one ignition fed B+ feed to all six injectors and so I can see all 6 current ramps.
    It depends on the wiring circuit layout of the vehicle and where you place your pickup.
    HTH

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    • racingdave
      Member
      • Jul 2009
      • 50

      #3
      current ramping

      Good info that is how i expected to see the injector pattern, so it sounds like i need to relocate my amps probe to the B+ wire feeding the three front injectors and adjust my time base.What do you mean by adjusting the time base and what are some basic starting points?Doesn't the VP auto adjust my scales?

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      • Crusty
        Senior Member
        • Dec 2007
        • 2450

        #4
        Originally posted by racingdave
        Good info that is how i expected to see the injector pattern, so it sounds like i need to relocate my amps probe to the B+ wire feeding the three front injectors and adjust my time base.What do you mean by adjusting the time base and what are some basic starting points?Doesn't the VP auto adjust my scales?
        I hook up my low amp probe to channel 1, then over in the bottom right, use channel 2 for the "sync" trigger which I'll hook up to the first injector in the sequence, let the channel 2 voltage start the trace.
        Injectors are usually only "on" for 2 to 6 ms so if the VP is at 20-ms, you'll probably only see the first injector.
        Remember to set the Ch-1 to about 5-Amps and the Ch-2 to 20-Volts.
        Yes the VP can "auto-detect" for you but play with the amplitudes and times. The longer the time and the higher the amplitude = less resolution but you can see more activities. To look closely at one item bring your amplitude down as low as will display and shorten the time = more resolution.
        When you have several waveforms on the screen, pop the throttle and you'll see the waveforms kinda pull themselves together briefly.
        Play with 20-ms for a starting point and take several "captures" of either screen shots &/or movies and play them back, both on the VP itself and in SSC-ShopStream-Connect.
        Last edited by Crusty; 11-20-2010, 12:25 PM. Reason: spelling

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        • racingdave
          Member
          • Jul 2009
          • 50

          #5
          current ramping

          Thanks Crusty for your help iam not at work today and didnot bring my VP home,iam looking forward to monday morning to try moving the low amps probe to the B+ feed to the front three injectors and do some adjusting to take a peek at the front three injectors.You say bottom right of VP for channel 2 sync trigger you say you are hooking up to first injector in the sequence are you hooking up the low amps probe or another adapter such as an rpm pickup and low amps probe?Too bad i dont have my VP now i would like to see what you are talking about.When you say i will probably only see the first injector do you mean thats all iam supposed to see at that time is only one, and i take it you want me to play with the amplitudes and times to see all of them?Ya know like kv voltage 4 clinders 4 spikes 6 cylinder 6 spikes an so on.And yes i would also assume i can do the same for ciol current ramping also.8 coils 8 ramps is that true?

          Comment

          • Crusty
            Senior Member
            • Dec 2007
            • 2450

            #6
            Hi RacingDave

            Top left corner, select full screen and digital. Now across the top will be boxes with min/max values along with the actual readings, same as a DMM. The rest of the screen is the "scope" which is displaying graphically an amplitude (vertical) and a time (horizontal).

            Bottom left, channel 1 is "displayed". Select channel 2 and select "display"
            Now you have both "active".
            Select your amperage scale for Ch-1. Then select your voltage scale for ch-2.

            Now in the bottom right is the "select trigger". Select Ch-2, either on the rising slope or the falling slope. Now the little "cross" on the screen can be moved to the left side of the scope display screen and this is where the "trace" will start.

            Wrap the Low amps probe around the feed wire for the front 3 injectors, and hook up the CH-2 green lead (I plug in the yellow wire to the green port so it gets grounded), and hook up the Ch-2 lead to the negative side of the first injector in the sequence.

            Now the first injector in the sequence is alive on ch-2 and also the trigger for the 3 amperage readings on Ch-1 which will then be in sequence so you can tell which injector of the 3 is which.

            With the time set to 20-ms, youll only see one injector pattern along with the voltage signal for that one injector. If you increase the time base to 100-ms or 200-ms or 500-ms, you'll then see two more current ramp readings but no voltage trigger, then if the time is long enough, you'll see the first injector along with the trigger, and then two more amperages for the next two injectors, and so on.

            You've got the idea.....
            Play with the time and the amplitude. Make sure your scales are in the appropriate values (Amperage vs Voltage)
            HTH

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