VWDiesel.net The IDI, TDI, and mTDI source.
General Information => FAQ/Tech Tips/Please Read First => Topic started by: Syncroincity on May 08, 2014, 12:47:33 am
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I have a nice fat 120 amp alternator out of a TDI attached to my AAZ install, the problem was; no W terminal to run the tach. I used a MKII "2.22" diesel tach fitted into my original Vanagon instrument cluster. I used this alternator to provide; 1. Clutched over-run pulley to take the strain off the AAZ crank nose with the serpentine setup, and 2. AMPS, baby.
Plastic cover and easily detachable brush pack... remove a few screws and you're looking at the stator windings. Check your brush condition while you're in here.
Photos are representative; not my alternator.
(http://www.myturbodiesel.com/images/b5/alt1.jpg)
(http://www.myturbodiesel.com/images/b5/alt4.jpg)
On these alts, the winding wires terminate in these little loops that mechanically crimp and lock them in. The outermost ones are what you need, one that does not connect to a diode. Red arrows in the pic below. (You can see the diodes below the other connections, round, fairly obvious.) Find one with a little space between the winding wires, or use a screwdriver blade to spread one open a bit. Clean with a wire brush to expose good bare metal, and loop a wire end into it and re-crimp the winding ends. Solder the wire. I had to use a butane torch, my soldering iron wouldn't quite heat everything up enough.
(http://images.thesamba.com/vw/gallery/pix/1204093.jpg)
In the Vanagon, connect that wire to the solid blue wire in your junction box if present.
Result: tachometer reading! I have no way to verify the RPMs, but it seems close to where it should be, a bit high maybe... shows about 900 at idle. The serpentine pulley is slightly smaller than the v-belt pulley. I'll have to go in and find the adjustment pot on the tach one of these days.
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good deal. It just picks up off one of the stator wires for the w signal then?
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I found a local shop that has new and ohc units with the W terminal
They offer powdercoated housings also for 45.00 in any color
I have a 90 and 120 amp core
GB
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There is an AAZ 120A alternator with a W terminal in the wild... I put one on my build. :-D But this is great for anyone that has a non-W alternator already!
Sent from my HTC One XL using Tapatalk
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good deal. It just picks up off one of the stator wires for the w signal then?
Exactly, and it doesn't matter which one you pick (there are six, 3 pairs), as long as you tap it before the diodes.
I'd seen a few how-to threads about this but all were kind of vague about wire placement, and most concerned the older style alternators.
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They offer powdercoated housings also for 45.00 in any color
This would be nice... All my AL components look like absolute crap.
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(http://[URL=http://s1134.photobucket.com/user/rodderboost/media/20140922_194315_zpsa32d5edc.jpg.html][IMG]http://i1134.photobucket.com/albums/m618/rodderboost/20140922_194315_zpsa32d5edc.jpg)[/URL][/img]
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(http://i1134.photobucket.com/albums/m618/rodderboost/20140922_194315_zpsa32d5edc.jpg) (http://s1134.photobucket.com/user/rodderboost/media/20140922_194315_zpsa32d5edc.jpg.html)
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I added this picture as I have an older 1Z/AHU alternator with the back plastic off and I removed brushes as I will likely replace them. I cannot tell with this one if a set (these stand upright towards the camera) is connecting to the diode. Is there a trick to telling what does and what does not?
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Are the center ones part of the diodes? Can a person use a ohm meter to test connectivity to them?
I saw on another site (4 x4 of some kind) had a picture quite similar and connected a wire to one of the six and his worked. I'm assuming like the one above it matters which of the six. do I need to take it apart further to see which are which?
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If you go from the top clockwise I tried the 4th one. No dice, did not have the signal or check with mutimeter. This post has a different alternator to start with, but I see the end posts both are useable. I'm going to try one of the end ones next. Pulled the alternator apart, nothing inside helps to determine which post will work.
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There are quite a lot of usable alternators that do have the 'W' terminal for what it's worth. I have a 120A serpentine one. For some reason a lot of the ABA motors have an alternator that came with a 'W' terminal, so there are loads of them available.
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vanbcguy, I have a ABA unit (that's what the car originally had in it) serp. I haven't even looked at it thinking it would not be worth even trying it assuming the mounting would be different and no W. Let me have a look at it later today as it is from an Can ABA motor. If it doesn't have a W I will certainly buy the one you have - maybe pm me price just in case.
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Hey sorry, I meant I have one on my car, not that I have one for sale...
Part number is AL0184X - I bought mine from FCP Euro
http://www.fcpeuro.com/products/volkswagen-alternator-cabrio-corrado-eurovan-golf-jetta-passat-transporter-al0184x
The 'W' terminal is on the 2-pin connector on the end of the alternator.
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Same one I used on my White alternator
GB
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Yeah, I have an alternator that has the W and installed it last night - was from the 2.0 ABA. Works fine. I have a new VDO tach, just have to set the pots later today and also has a potentiometer so if it's off a bit I can adjust it. I bought a cheap china electronic hand held tach, Just add a piece of it's reflective sticker to the crank and it tells speed - seems like it works well enough. Will adjust the VDO to match it - cause I hate not having a tach.
Thanks for the help!
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I now have a working tach - current idle is about 786, by my cheap china hand held, so I set it to just below the 800 mark.
W alternator is so much easier than finding a winding before the doide on this type of alternator - in my opinion. I'm have virtually no electronics experience ...
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I'm also getting ready for a mTDI (AHU) conversion in my Westy as well and was looking for an alternator that would mount to the block that would accept the W terminal.
Reading this post the AL0184X would be a good way to obtain the W terminal.
I have the following questions:
Does this alternator have the same/similar RPM setups for the diesels?
What is required for getting the proper Tach RPM's setup for an mk2 (CE1 diesel tachometer?) configured properly for RPMs? Should an m-TDI AHU idle around 750?
Thanks! Really hoping to get a tachometer solution figured out for my conversion.
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I have the AL0184X on mine... Works fine.
The tach you have should just plug in and work if it's for a diesel. No magic... Not sure if there is an adjustment on those older ones, I don't think there is. The tach will be approximately right though.
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There is an adjustment pot in the circuit of each of the tachs back to mk1.
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Thanks Libby, sounds like a better option for a mTDI setup would be using the AL0184X with the W terminal. That way there's no prying off the plastic back and soldering a wire to a stock TDI alternator.
There is an adjustment pot in the circuit of each of the tachs back to mk1.
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Swapping a 1.6 TD JX for a 1.9 mTDI AFN in a '91 Syncro Doka.
The bright shiny new Bosch Alternator Model No. AL0723X that came with the AFN does not have an explicitly W signal, rather B+, D+ and finally DF. I have seen pics above of the AL0184X where the W connection is exactly where the 0723X places the DF in a two pin connector. When looking at AHU wiring schematics it appears the DF signal is effectively equivalent to the W but that's a simplified schematic and is without looking at the alternator internals or the mfr's internal schematic. Does anyone know if the connecting the JX's W wire to the alternator's DF terminal will accomplish the tach signal objective? I don't want to void the warranty on the new alternator by making the above mods.
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The AHU alternators I have used have had the W terminal as a marked connection. I have not used an AFN alt.
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Check your brushes and if not, see maybe where the cable does not connect at the alternator, how it connects