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Alternator output
#0, Alternator output
Posted by moo fish on Dec-08-03 at 06:33 AM
Is there such a thing as a sticky votage regulator? Of late, when I crank up the 40A, the volt meter on the dash is at 12 volts. Give it some throttle (2000 rpms) and it kicks up to 13+ volts. Back off the throttle and it still reads 13+ volts. Seems to be SOP. Do the contacts on the VR need to be burnished? My first reactio was to hose down the VR with WD40 but, first, some feedback please.....rt on the Moo Fish
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#1, RE: Alternator output
Posted by NoSlack on Dec-08-03 at 10:04 AM
In response to message #0
LAST EDITED ON Dec-08-03 AT 10:12 AM (PST)
I think the voltage regulation is all done internally. I have to kick mine up a few RPM to bring the voltage up as well, but not as high as 2000.
Mike
EDIT: on the older style there is a wire that comes from the instrament panel that needs to be hot(+ voltage) to starts the excitation. If I make it home before 10PM, I'll look at the wiring diagram to refresh my memory.
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#2, RE: Alternator output
Posted by DOGHOUSE26 on Dec-08-03 at 10:57 PM
In response to message #1
I have the same problem on my 41P. I only need about 1000-1200 RPM to click it over or I can turn the key middle position for a split second and then turn it back on and it will kick over to 13.8 volts. If I'm on a 2 day trip generally the next morning it pops right back to 13.8 on the first start. When I had the alternator rebuilt it didn't stay below 12 volts for the first season however the following summer it started doing the same thing. I just got used to it.
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#3, RE: Alternator output
Posted by NoSlack on Dec-09-03 at 06:22 PM
In response to message #0
I took a look at the wiring diagram and found were the excitation wire comes from.
If you are still running the old style alternator(3 wires on the back)you will have a #10 or 12 red wire as your +, a #10 or 12 dark blue as your - and a smaller #14 black wire that needs to go hot to get the alternator to put out. The other end of the small black wire is landed on a 69 ohm resistor(1" square, mounted in a bracket behind the instrument panel). The other end of the resistor has a green wire on it that jumpers to all the gauges. The green wire is the key switched hot for the gauges.
Check all the connections from the green wire on the key switch through the resistor and the multi pin connector on both end of the wiring harness running between the instrament panel and the engine wiring harness.
The other thing you could do is install a 90 amp self exciting alternator like I did and tape off the small black wire at the alternator.
Mike
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#4, RE: Alternator output
Posted by moo fish on Dec-10-03 at 05:52 AM
In response to message #3
I will check this out. The back of my dash is a real mess with 20 years of splices, crimps, and shrinkwrap. Of course, didn't happen on my watch. Another observation: the VDC (measured through the Garmin GPS unit)slowly builds from 13.2 to 13.9 as the engine runs.....rt
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#5, RE: Alternator output
Posted by Capt Art on Dec-16-03 at 08:32 AM
In response to message #4
Mike,
I am interested in upgrading to the self exciting alternator you mentioned. Can you get me a part number, manufacturer, etc? I assune it justed bolted right on. Also, did you have to transfer the old pulley or did it come with the correct pulley for your diesel? Thanks for ouyr help.
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#6, RE: Alternator output
Posted by NoSlack on Dec-16-03 at 10:06 PM
In response to message #5
I suspected I had a shorted diode in my old alternator so I took it to a shop near my work for testing. Sure enough the unit was bad and they suggested I go with a high output (90 amp), self excited unit.
If you go with a high output unit you need to upgrade the wires to handle the extra current.
The positive wire daisy chains from the alternator to the glowplug relay to the start relay and then meets up with the large battery positive on the starter. You need to replace all that wire with a #6 fine strand marine grade wire. The negative was not as complicated if I remember correctly.
I believe they used the pulley off my old unit. You will also need to check the belt alignment and shim the alternator forward or aft to make the pulleys parallel. If I remember correctly the pivot point on the alternator can adjusted to bring the alignment into spec.
The name of the business is PG Auto Parts Electrical Specialists.
I will swing by there tomorrow with my invoice and get a brand name for you.
Mike
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#7, RE: Alternator output
Posted by NoSlack on Dec-17-03 at 01:27 PM
In response to message #5
Here is the low down on the alternator:
Motorola 110-603,12V 95 amp output, $187
If you need a 2 belt pulley that fits the Motorola, they are $20.
There is also a spacer you might need for the mounting bolt that is $8.
I would think you can locate one of these unit up your way at a good auto electric shop.
Mike
