idle reads 1500 and i think clocks runs 2x am i missing something i got replace alt last year Cummins John Deere Alternator 3604480RX, 3675270NW, RE509106 wrong alt ?? it charges good .
Does the tach read off the alternator? Mine wouldn't read anything until I replaced the regulator. Unless the new alt is 24v on a 12v system, I don't see how your tach and clock can be off. Are you talking hour meter and/or time of day clock?
hour meter no clock would there be a 4.6.8 cyl swicth in back off tach maybe? would a 24 vt alt kill battery ? no big deal but hours gonna be off if i ever sell
Not sure, is this a new instal? Some could be a wire to cut. Kill it dead! Boil the crap out of it! Not to mention it could fry the electronics, lights etc. Do you have access to a volt meter?
That part number is a 12V alternator, fits 580K with 4-390 engine, 1986-1994. Different alternators put out different pulses, and pulley size matters also of course, so if the tach runs off the alternator signal, I don't think there's a lot you can do unless you want to buy a programmable tach and set it to match. Check the back of the tach and see if there's a rotary switch, line of DIP switches, rubber plug that pops out with switches under it, you may have a programmable. 4/6/8 switches are only for gas engines usually.
The pin on the left of your picture, the one all alone thats marked with a "W" is usually for the tach.