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Unread 06-09-2010, 06:48 AM   #16
Web Wheeler
1989 YJ Wrangler 
Join Date: Apr 2008
Location: Detroit, Michigan
Posts: 19,986
Yes, anything with the ECU SBEC1 will have the engine controller in the engine compartment and will have the ECU controlling charge. The answer to the second statement about the guage is a litle more involved. You primary vehicle supply for the power when the vehicle is running is the alternator, not the battery. The reason the alternators went to extewrnally regulated is because the control circuits changes and became digital. The output to control the power is actually a modulated signal that varies with load. The reason the circuit was put in the controller was because the controller had inputs for fuel and timing. This gave the controller the ability to decrease and increase the fuel and timing with the load requirements and give better milage and faster response to demand. As for the voltage reading question. Where you measure from as far as a point in the system is not really as important as long as the voltage drop for the wiring is compensated for in the guages reading. There is an adjustment writeup someone posted. As for the controller and the 5 and 8Vdc power supplies. They are regulated by 2 internal voltage regulators. The voltage regualtors are spec'd not to vary the output voltages down to 9Vdc and the controller itself is suppose to function as a system down to 6Vdc. I wouldnt recommend doing it for a extended length of time but that is design standard. I hope I answered your questions.

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Unread 06-09-2010, 10:02 PM   #17
Registered User
1990 YJ Wrangler 
Join Date: Jan 2009
Location: NA
Posts: 1,584
Originally Posted by sentinal02 View Post
check out the diagram attached. pin 20 on the PCM drives the field of the alt. the alt still rectifies the output as usual of course, but the regulator has been moved to the computer. what really sucks is when the regulator goes, the whole computer needs replacing. like you said, it's a round about way of doing things and it does make you wonder what the advantage is.
Amazing. Thanks.
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