Oneof6· Premium Member
So said:John, I am glad that your ordeal with you parasitic discharge (that sounds nasty don it?). I commend you on your tenacity and thank you for keeping us up to date on the solution process. I certainly came away learning more about this avenue of system diagnostics.
However, I am not convinced that on all 7.3 PDS vehicles that the alternator does not contribute until the glow plugs cycle off. That hypothesis is in opposition to my own test data that provided and my interpretation of the charging schematic.
I will provide that test data, again, attached. In the first DCV vs Time plot one can easily see that immediatly after the identified start with starter drain, GP's still on, voltage is being contributed as the GP's finish their time cycle and see the exact moment that the GP's time out and the full contribution of the alternator pushes the charging voltage up to the regulated limit.
I am open to believing that there may be differences in my 135 Amp alternator and your significantly larger capacity alternator effecting this curiosity.
If someone can provide data, alternate schematic or printed data from Ford I would appreciate seeing it.
John, if you you are data curious, like me, and would like to DM me your address and contact info I can mail you my data logger, the device support software is OEM free online. You could run your own DCV vs Time strart test or tests and send the data logger back when you are finished.
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