Dodge/Jeep Alternator control

[Fringeless]

I am trying to figure out how to control the alternator in my 92 Cherokee (voltage regulator is in stock ECU) with my 3.57/ms3x. I have searched and searched to no avail. I need to know what output/s are suitable, tunerstudio settings, and if I need to make any provisions on board, eg. resistors, jumpers and so on.
Enlighten me please.

[Matt Cramer]

Check the resistance between the two Field terminals and let me know what you measure.

[Fringeless]

I checked it cold @ 70deg. Mr. Fluke says 2.6 ohms.

[Fringeless]

I made an error. I have an ms3 v3.0 with ms3x.

[Matt Cramer]

OK, so this might be drawing as much as 6 amps if the voltage spikes. You could control this with a main board injector driver.

[Fringeless]

That is great, I will use the inj bank 1 output.

[Fringeless]

Well, I tested it with the Chrysler settings. The voltage output of alt would slowly oscillate from 13v to 16 or so. Well before I could do any more ahem, "testing" I tryed to change the freq. and it shot up to 17v and popped the cherry of the Inj bank 1.. gotta check Q9 and ancillaries. Not a prob for me. Just need to figure out settings on TS.

[jsmcortina]

"High Speed Field Switching" is the setting you want.

James

[Fringeless]

Will try once I get inj B 1 circuit repaired.

[jsmcortina]

When bench testing with a Jeep alternator I used a 1N4004 diode across the field coil. Banded end to 12V.

James

[Fringeless]

James, can you explain more. Are you saying that you used a diode on the switching leg (in my case earth/gnd voltage) or on the positive side (from vehicle relay +12v) to field? I must make a note here. I plugged my stock ecu back in (I build a weatherproof breakout box/ patch-interface from a circa 1940's US steel first-aid kit using stock ECU circuit board header and wiring harness wiring is pinned to board mounted terminal blocks). This allows me to unplug MS and return to stock ecu- for purpose of redundancy. Well, on to my note. When I plugged the stock ecu back in, I had the same problem. The alternator shot up to 20 volts. The surge took out the stock voltage regulator (external) in the Jeep ECU. I back probed the field circuit and it was grounded, thereby allowing the field to go "wide open". I thought that I had a short-to-ground in the wiring. However, Upon further inspection, I isolated the short to the Alt. One of the slip rings had shorted to ground by an accumulation of brush dust. I blew it out with air and painted the case and metal portion of the shaft near the slip ring to isolate ground. The alt was a reman unit less than 6 mo. old and the slip rings were rough as all hell, eating the brushes down to the springs. I tossed it in the lathe and tossed in a new brush holder.

Just had to share, had never seen anything like it.