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Engine Specific Info and Questions => IDI Engine => Topic started by: 92EcoDiesel Jetta on November 28, 2012, 03:44:01 pm
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I snapped this pic of the alternator p/n 175 903 023P on my 81 Caddy before it got dark and didn't have time to investigate further. There is a plug with 3 wires going to the alternator, there are no screw terminals or spade lugs like the alternator on my 92 Eco. Having 3 wires suggests it is a W terminal alternator: One wire to the battery for charging, one wire for the excitation. I am hoping the 3rd wire is the W terminal and I hope it runs all the way up to the correct pin in the cluster connector. I just modded a gasser tach to diesel per regcheesman's writeup and looking forward to installing it and see if the tach works.
(http://i1183.photobucket.com/albums/x480/Ecodiesel92/IMG_20121128_144127.jpg)
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Don't you own a flashlight? lol
I have a very similar alternator with only a few digits different in the numbers. Mine has a W terminal and the photo below shows where it is (right side of the back of the alternator when sitting in its mounted position).
(http://onespeedfast.com/rabbit-forums/motorola-2.jpg)
And here is the tag on mine:
(http://onespeedfast.com/rabbit-forums/motorola-1.jpg)
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The three wires in that plug are B+, B+, and D+. The two fat red ones go to the battery (sometimes by way of the starter motor) and the other one, usually blue goes to the charging light.
My alternator has a terminal that looks like the W on the second one posted, but isn't a W signal.
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The three wires in that plug are B+, B+, and D+. The two fat red ones go to the battery (sometimes by way of the starter motor) and the other one, usually blue goes to the charging light.
My alternator has a terminal that looks like the W on the second one posted, but isn't a W signal.
Thanks for the info! Looks like I'm gonna have to pull the alternator, solder a wire onto a diode and make it a W terminal unit. At least it looks easy compared to my 92 Eco with AC, one belt and it's off!
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Autozone alternators have w terminals and cost about 60 bucks
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Autozone alternators have w terminals and cost about 60 bucks
Good to know! What year and model should I ask for? Note that mine makes the connection to the alternator via one 3 prong molded rubber plug (with 3 female spade terminals in it). No AC.
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My car is an 81 Rabbit pa with ac
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My car is an 81 Rabbit pa with ac
Does "Autozone alternators have w terminals and cost about 60 bucks " still apply to my Caddy?
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My car is an 81 Rabbit pa with ac
Does "Autozone alternators have w terminals and cost about 60 bucks " still apply to my Caddy?
yes, the only difference is the ac. just go order one, if it shows up with out the w terminal tell them you don't want it, it doesn't cost you anything. i ordered 4 alternators through napa, the first one i just hope it was right, then the second one they actually called the warehouse and told them specifically not to send it unless it had the w terminal, they did that 3 more times, then i just went to autozone. i work for napa and get an employee discount so i was trying to go there first.
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My car is an 81 Rabbit pa with ac
Does "Autozone alternators have w terminals and cost about 60 bucks " still apply to my Caddy?
yes, the only difference is the ac. just go order one, if it shows up with out the w terminal tell them you don't want it, it doesn't cost you anything. i ordered 4 alternators through napa, the first one i just hope it was right, then the second one they actually called the warehouse and told them specifically not to send it unless it had the w terminal, they did that 3 more times, then i just went to autozone. i work for napa and get an employee discount so i was trying to go there first.
Autozone only has the AC alt ($59). The non AC alt is $79 but not available from their supplier so I', SOL. I already have my alternator out and will take the cover off to get to the diodes and bring the W terminal out. This Motorola alternator has the regulator in a separate module from the brushes, unlike the Bosch which is in one assembly. Did 81 Caddy w/o AC come with Motorola alternators exclusively or did it also come with Bosch?
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The truck my cousin has sitting in his yard has the the motorola alternator, so I am goin out on a limb and saying yes.
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The truck my cousin has sitting in his yard has the the motorola alternator, so I am goin out on a limb and saying yes.
Motorola alts were junk.. i just scrapped a big pile of them.
i always replace them with bosch units. ive found that the early-ish rabbits had the moto..
but the motorolas were interchangable with the bosch unit, and cheaper, so people often times bought the moto as a replacement for the bosch.
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The truck my cousin has sitting in his yard has the the motorola alternator, so I am goin out on a limb and saying yes.
Motorola alts were junk.. i just scrapped a big pile of them.
i always replace them with bosch units. ive found that the early-ish rabbits had the moto..
but the motorolas were interchangable with the bosch unit, and cheaper, so people often times bought the moto as a replacement for the bosch.
Why are Motorola alt junk and what fails in them? Do you have a good Bosch non AC alt with a W terminal you want to sell?
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I've soldered a wire to the diodes to bring out the W terminal (shiny solder spot at 10 o'clock in the pic). Next reinstall then test and see if the tach works.
(http://i1183.photobucket.com/albums/x480/Ecodiesel92/IMG_20121130_125323.jpg)
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i hope you have put it in the right spot, other wise you could potentially be supply the tachs w terminal with un regulated voltage, to create a w terminal i believe you want to tap into just one of the three black wires.
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I ran Motorolas for hundreds of thousands of miles and rarely ever had bearings or brushes wear out. I found them to be much more reliable than the Bosch, hands down, on either diesel or gasoline. I owned Bosch the whole time and kept one under the seat just in case I needed it.......rarely did. And, my 82 Jetta had 435,000 miles on it. I have no idea what this other guy is taking about.
I continue to run a Motorola on one of my gas cars....never a problem.
I also have a Motorola on the last tractor I own......2510 John Deere.....and that alt. has only needed attention twice in 9800 hours.
There, how is that for reliability?
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I ran Motorolas for hundreds of thousands of miles and rarely ever had bearings or brushes wear out. I found them to be much more reliable than the Bosch, hands down, on either diesel or gasoline. I owned Bosch the whole time and kept one under the seat just in case I needed it.......rarely did. And, my 82 Jetta had 435,000 miles on it. I have no idea what this other guy is taking about.
I continue to run a Motorola on one of my gas cars....never a problem.
I also have a Motorola on the last tractor I own......2510 John Deere.....and that alt. has only needed attention twice in 9800 hours.
There, how is that for reliability?
OK I feel better now. The bearings on mine still feels fine, the brushes are on the short side but serviceable. I like to get an extra set of Motorola brushes and a regulator to keep in the Caddy as spares. Anyone have what I'm looking for?
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i hope you have put it in the right spot, other wise you could potentially be supply the tachs w terminal with un regulated voltage, to create a w terminal i believe you want to tap into just one of the three black wires.
I am 99.9% sure I put it in the right spot, having ohmed out the diodes to D+, B+ and gnd. Those 3 black wires terminates to the diode pack, one of which goes to the spot where I soldered to. I did not want to cut into the black wires nor remove the diode pack for fear of damaging the wires since they are old and stiff, so soldering at that spot seems to be least intrusive.
Shouldn't the W terminal be un-regulated AC, coming off one of the 3 phase windings before they are full wave rectified? ???
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U got it
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Installed modded W terminal alternator into the Caddy and checked it out with a DVM on both AC and DC scales. Alternator is charging fine @ 14 VDC. The W terminal measured 7.5 V AC which as I recall, is the same as the OE W terminal alternator on my 92 Eco so the W terminal mod I made is working. Have not hooked up the modded W terminal gasser tach yet but that'll be next.
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Installed the cluster with the W terminal modded tach board hanging out so I can adjust it. I calibrated it with a phototach at 1000, 2000, and 3000 RPM and it appears to be accurate enough. This tach board is actually from a CE1 gasser tach. The Westmoreland tach that I started with didn't work for some reason after modification. I will go back to it and try again ( I think I screwed up by leaving a capacitor out).
CLICK TO PLAY!
(http://i1183.photobucket.com/albums/x480/Ecodiesel92/th_VID_20121205_141301.jpg) (http://i1183.photobucket.com/albums/x480/Ecodiesel92/VID_20121205_141301.mp4)
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That's nice. ;D
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I ran Motorolas for hundreds of thousands of miles and rarely ever had bearings or brushes wear out. I found them to be much more reliable than the Bosch, hands down, on either diesel or gasoline. I owned Bosch the whole time and kept one under the seat just in case I needed it.......rarely did. And, my 82 Jetta had 435,000 miles on it. I have no idea what this other guy is taking about.
I continue to run a Motorola on one of my gas cars....never a problem.
I also have a Motorola on the last tractor I own......2510 John Deere.....and that alt. has only needed attention twice in 9800 hours.
There, how is that for reliability?
my results were 100% backwards of yours...