r25 alternator wiring

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farmerdave

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I'm having a few problems with the alternator wiring on my r25 v6. The unit is the original Paris-rhone 105amp, and has been converted to a bosch external regulator.
The alternator and regulator have been checked out by an auto electrician and are OK, his opinion of the P-R unit was quite good (when the regulator is changed to an external unit)
The problem seems to be that when the plug with the grey and white wires is plugged in to the back of the alternator, the grey wire heats up very quickly. One of the yellow wires to the ignition switch also becomes hot :dead: . This only occurs when the ignition is turned on. Auto electrician doesn't know what is causing this problem.
Yesterday evening I accidentally plugged the wiring into the back of the alternator with the ignition on, and the fuel pump ran and the starter motor tried to turn over. Argh!.

Any ideas on what may be causing this??. Trying to find the fault is driving me nuts :mallet: :mallet:

Farmerdave
 
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I looked into converting to an external reg, but decided against it, as it was going to cost as much as a new internal, but was going to involve a bit of mucking about modifying the alternator. I reckon you may have issues with this and will need to pull the lot out and start from scratch in working out whats wrong. May be easier to put it all back to standard.
PR regs are expensive, but not super expensive ( ~$90) and do last for a long time if things are kept clean (alternators dont like getting greasy and gruby - it holds moisture in them)

without knowing exactly how the unit was modified, I doubt we can help ;)
 
Not sure if this will help,

But I looked up an alternator service manual which covers Paris Rhone 12 volt type A13M3, A13R52, A13M, A13R, In the A13M3 description it mentions there is provision for diodes in the system to prevent return of current from the battery. (Isolating diodes) (also silicon rectifiers that perform a similar function in some models)

"In the case of the A13M3 Alternator only one diode blocks the return passage between battery and the winding whilst on the A13M model with isolator Diode and any of the three phase alternators, there are always two diodes in series, thus providing double protection. For the A13M3 a fuse link is connected in series with each diode, and its main function is to melt should the respecive diode be short-circuited. CAUTION: Any reverse of polarity between battery and alternator will damage the diode beyond repair."

Without knowing if any of these models of alternator is the one fitted, I don't think that there is any point in giving more detailed information from the manual.

If your alternator is one of those models listed above, I could forward you the technical information for that specific alternator, there is also information as to the external regulators (AYA 21) (AYA 213) fitted to some alternators also in the manual - unfortunately it does not list the cars or models these were fitted too.

Ken.
 
Of course. Diodes are one of the things that had to be modified when converting to an external regulator. Odds on that this is your problem, which will relativly easy for an auto elec to fix once it is removed.
 
Ok, some good ideas here. Back to basics.
The alternator fitted is the Paris Rhone A14N 76. I pulled the cover off the back tonight and had another good look at what had been done in the conversion. It seems that while the regulator and internal wiring had been modified, the original connection plug on the wiring loom was retained and when plugged into the alternator made incorrect (shortcircuit) connections. Not at all logical, but maddeningly (is that a word?) simple to fix.
It works now, no smoke or other bad omens. And the charge light works as intended!. Thanks for all the help. :adrink: :cheers:
BTW, does anyone else have a stainless steel heatsheild on the back of their PR alternator?- odd looking thing, maybe an afterthought?

Regards,
Farmerdave
 
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