Relative compression testing

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  • BRIAN617
    Senior Member
    • Dec 2016
    • 153

    Relative compression testing

    Couple years ago I bought an amp clamp for relative compression testing with my Snap On Modis. After a several failed attempts I've either bought the wrong clamp or just don't know how to set up my Modis properly.

    The clamp I bought is an OTC 3500-01a 600amp ac/dc current clamp. Wrong clamp or just dummy at the wheel?

    If wrong clamp, recommended clamp for relative comp, injector/coil pack, parasitic draw testing?
  • greasybob
    Senior Member
    • May 2008
    • 1590

    #2
    Any clamp should work as long as can get it to fit around the battery cable and has it's own power supply. You'll have to figure out what the conversion rate is, amps to voltage, so it will display on the scope. Around a 2 second time sweep. Start at about 100 mV setting maybe switch to AC couple.

    Comment

    • Witsend
      Banned
      • Nov 2012
      • 2942

      #3
      Seems like with DIS waste spark ignition systems, My Counselor 2 often fails and gives me error message attempting cranking amp tests. Think it just gropes with the task of differentiating true from waste spark at erratic rpm on the #1 one wire trigger pickup. Wish it just had a modern low amp probe pickup that could get into a tighter area and it put around #1 fuel injector control wire or #1 coil wire of COP wire.

      Comment

      • BRIAN617
        Senior Member
        • Dec 2016
        • 153

        #4
        Thanks Bob, next chance I get to fool with it I'll report back.

        Comment

        • Wheel
          Senior Member
          • Jul 2007
          • 719

          #5
          Originally posted by Witsend
          Seems like with DIS waste spark ignition systems, My Counselor 2 often fails and gives me error message attempting cranking amp tests. Think it just gropes with the task of differentiating true from waste spark at erratic rpm on the #1 one wire trigger pickup. Wish it just had a modern low amp probe pickup that could get into a tighter area and it put around #1 fuel injector control wire or #1 coil wire of COP wire.
          Actually if I am not mistaken, your #1 pickup should be sensitive enough to pick up from an injector or primary ignition wire to trigger from it. Be aware that #1 plug and #1 injector can fire at very different times. Try it!
          You can expect the reputation of your business to be no better than the cheapest item or service you are willing to sell. - Wheel

          Comment

          • jm43130
            Senior Member
            • Apr 2008
            • 182

            #6
            This is for Witsend. I still have my Counselor 2 and I have a rpm sensor that goes with it. looks like a amp probe, but has the wheel that you run on the fan belts. That works okay. using #1 as a trigger, just hold the wheel on "running " belt. It is a MT3000-420, power balance probe.

            Comment

            • Witsend
              Banned
              • Nov 2012
              • 2942

              #7
              Actually if I am not mistaken, your #1 pickup should be sensitive enough to pick up from an injector or primary ignition wire to trigger from it. Be aware that #1 plug and #1 injector can fire at very different times. Try it!
              I believe it works too , but the #1 pickup is just too bulky to get into tight areas to be of any use . I figure if i picked up a low cost generic low amp probe and made some sort of go between coupler with a 9 hole barrel connector and correct terminals , I could possibly make another trigger adapter. I would also like to get a 16 hole barrel connector and try to make a pressure transducer to use with it , but it would be nice to know the pin out of the cable terminals of what each terminal is for.

              Tips, tricks, questions and suggestions... Discuss Instrumentation and information for testing vehicles at the component level.

              Comment

              • BRIAN617
                Senior Member
                • Dec 2016
                • 153

                #8
                Anyone interested in a Counselor 2? We have one here in the office just collecting dust.

                Comment

                • Witsend
                  Banned
                  • Nov 2012
                  • 2942

                  #9
                  This is for Witsend. I still have my Counselor 2 and I have a rpm sensor that goes with it. looks like a amp probe, but has the wheel that you run on the fan belts. That works okay. using #1 as a trigger, just hold the wheel on "running " belt. It is a MT3000-420, power balance probe.
                  I don't have the rpm sensor . How would that thing work? Put a white grease pen mark across the belt and that is sensed? Do you generally need the rpm sensor when performing cranking amps test on a car with a waste spark ignition system? What would be your trigger then to determine which cylinder on the cranking amp bar graph is #1?

                  Anyone interested in a Counselor 2? We have one here in the office just collecting dust.
                  I have a clear plastic dust cover that goes over the scribe printer and Counselor 2 but sides are becoming unstitched and I need to sew the sides together because the dust is still finding a way in .
                  Think I would use mine more if I figure out how to make a custom pressure transducer, and a maybe a tight quarters#1 Trigger out of cheap Hantech Low amp probe. Any old Engineering information available about what pin is what on the barrel connectors of each cable

                  Comment

                  • jm43130
                    Senior Member
                    • Apr 2008
                    • 182

                    #10
                    No , Rpm sensor looks just like a cranking amps pattern, since it is synced by #1 cylinder clamp. As a cylinder fires, rpm speeds up, you can see top of pattern as lower on a cylinder that doesn't fire as good, or has lower compression.
                    Witsend, I also have pinout diagrams for those 9 and 16 barrel pins you are interested in. They are contained in the big thick manual that came with the Counselor 2. If you need, message me, I can fax or email to you. Maybe you can make something work for you. There also originally was a vacuum probe for Counselor, I have that also. It has same type of pattern as cranking amps. It just graphs vacuum surges.

                    Comment

                    • Wheel
                      Senior Member
                      • Jul 2007
                      • 719

                      #11
                      Originally posted by Witsend
                      I don't have the rpm sensor . How would that thing work? Put a white grease pen mark across the belt and that is sensed? Do you generally need the rpm sensor when performing cranking amps test on a car with a waste spark ignition system? What would be your trigger then to determine which cylinder on the cranking amp bar graph is #1?



                      I have a clear plastic dust cover that goes over the scribe printer and Counselor 2 but sides are becoming unstitched and I need to sew the sides together because the dust is still finding a way in .
                      Think I would use mine more if I figure out how to make a custom pressure transducer, and a maybe a tight quarters#1 Trigger out of cheap Hantech Low amp probe. Any old Engineering information available about what pin is what on the barrel connectors of each cable
                      There were 2 styles of #1 trigger pickup on these: an earlier (more cumbersome) red one, and the later gray one, which is more like the one the Verus now uses, which is close to the size of most low amp probes. Which is yours?
                      You can expect the reputation of your business to be no better than the cheapest item or service you are willing to sell. - Wheel

                      Comment

                      • Wheel
                        Senior Member
                        • Jul 2007
                        • 719

                        #12
                        Originally posted by Witsend
                        Seems like with DIS waste spark ignition systems, My Counselor 2 often fails and gives me error message attempting cranking amp tests. Think it just gropes with the task of differentiating true from waste spark at erratic rpm on the #1 one wire trigger pickup. Wish it just had a modern low amp probe pickup that could get into a tighter area and it put around #1 fuel injector control wire or #1 coil wire of COP wire.
                        They actually had a special low amp probe for it that works really well. Trouble is you couldn't use it and the high amp probe at the same time. It didn't take me long to replace the little alligator clips on the white and red auxiliary leads with banana plug ends to allow more flexibility to use other equipment and probes
                        with it. You can get various adapters at AESwave to help also once you make this conversion. Their software also allows you to save your Counselor screenshots to a computer if you need to save them. You might also find something to help with your transducer needs there.
                        You can expect the reputation of your business to be no better than the cheapest item or service you are willing to sell. - Wheel

                        Comment

                        • Wheel
                          Senior Member
                          • Jul 2007
                          • 719

                          #13
                          Originally posted by Witsend
                          I believe it works too , but the #1 pickup is just too bulky to get into tight areas to be of any use . I figure if i picked up a low cost generic low amp probe and made some sort of go between coupler with a 9 hole barrel connector and correct terminals , I could possibly make another trigger adapter. I would also like to get a 16 hole barrel connector and try to make a pressure transducer to use with it , but it would be nice to know the pin out of the cable terminals of what each terminal is for.

                          http://productforum.autorepairdata.c...ad.php?t=11515
                          The input & output voltages feeding the transducer would also have to be compatible. You can buy transducer kits or accessories for voltmeters or scopes
                          that have the little boxes that run on batteries and power up the transducers and output a given voltage per psi to your scope. I believe the sun scopes of the era actually used the Snap On transducers currently available. Might be interesting if one could find some of those leads from one.
                          You can expect the reputation of your business to be no better than the cheapest item or service you are willing to sell. - Wheel

                          Comment

                          • Witsend
                            Banned
                            • Nov 2012
                            • 2942

                            #14
                            I actually found My #1 pickup on my Counselor2 was getting an open circuit There are 4 pins on the #1 pickup 9 hole J5 barrel connector and no pins on the pickup side had any continuity across any of each other. The rubber strain relief at the pickup end was broke so I took the pickup apart and found only 2 wires of the 4 wires actually do make a connection to the pickup and the splice of the white wire to the yellow inside the pickup was cracked causing an open. The red wire appears to be intentionally folded back away from connecting to the green wire I see coming out of the pickup and no shrink tube was laying inside The white wire (clear?) goes to pin 4 and the black wire to pin 3 of the connector. The other red wire that goes to pin 5 I suspect is not used and a bare silver shield wire inside just serves as a shield against errant sparking.
                            I hate how damn bulky the #1 pickup of this Counselor2 is to get around a fuel injector pigtail or COP pigtail and the less bulky pickup ohmed out about 1 ohm or the same , so I spliced the less bulky pickup on. Unfortunately it did not pick up rpm signal from the fuel injector pigtail , and when hooked to one of the DIS cables on 6 cylinder explorer showed an error message and less than 300 rpm.
                            Is there a less bulky alternative #1 pickup that can be used on a Counselor 2 that is also sensitive enough to work as a rpm trigger off a COP primary pigtail or a pigtail off a fuel injector?
                            Attached Files
                            Last edited by Witsend; 02-02-2017, 06:06 PM.

                            Comment

                            • Witsend
                              Banned
                              • Nov 2012
                              • 2942

                              #15
                              Oops

                              Now this is better. Had the #1 pickup plugged into the secondary J4 barrel connector instead of the correct #1 J5 barrel connector. So I guess it does works off ignition secondary wire but off a fuel injector pigtail close to the coil pack it was reading like 8 thousand rpm , so I will experiment and try to shield the wire to the pickup better. Still makes me aggravated that I have to put a oring around cheap POS to hold the thing closed better to maintain a rpm signal from pickup

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