v3.0 VR input, questions
Posted: Thu Apr 12, 2012 7:50 am
I am in the process of doing a couple of microsquirt based EFI systems, for a local engine shop. I am planning on using a distributor with a VR pickup. I have a few weeks for bench testing and harness build, but need it to be as solid as possible when the time comes to run on the dyno, and have several questions:
1) To determine VR sensor polarity with my previous MS builds, I always pull a ferrous object away from the sensor rapidly, and note voltmeter readings. I have always call polarity "correct" (meter (+) on sensor (+), meter (-) on sensor (-) when voltage goes negative with a leaving target. Is this the "correct" thing to do?
2) I see mention of placing a resistor across the VR wires so that the adaptive noise rejection functions of the new chip works properly. Troubleshooting this system on the dyno if I am wrong is not an option. If I can bench test previously, would I be most safe to install the resistor, and check that it is still possible to obtain good low speed (lower than expected cranking rpm) sync?
3) The distributor we are using also normally has a module capable of firing a coil. If I were forced to use this module for input conditioning, I would assume I would use the "Opto" method. My understand of this is 12v (+) on VR (+), Opto (-) on that modules ground, and Opto (+) on the output from the module that would trigger the coil (coil not installed). Is this a correct assumption, or with no coil do I also need a pullup from 12v (+) to Opto (+)?
1) To determine VR sensor polarity with my previous MS builds, I always pull a ferrous object away from the sensor rapidly, and note voltmeter readings. I have always call polarity "correct" (meter (+) on sensor (+), meter (-) on sensor (-) when voltage goes negative with a leaving target. Is this the "correct" thing to do?
2) I see mention of placing a resistor across the VR wires so that the adaptive noise rejection functions of the new chip works properly. Troubleshooting this system on the dyno if I am wrong is not an option. If I can bench test previously, would I be most safe to install the resistor, and check that it is still possible to obtain good low speed (lower than expected cranking rpm) sync?
3) The distributor we are using also normally has a module capable of firing a coil. If I were forced to use this module for input conditioning, I would assume I would use the "Opto" method. My understand of this is 12v (+) on VR (+), Opto (-) on that modules ground, and Opto (+) on the output from the module that would trigger the coil (coil not installed). Is this a correct assumption, or with no coil do I also need a pullup from 12v (+) to Opto (+)?