Voltage Regular for Paris-Rhone Alternator, 1-Wire? 2-Wire?
 

Hi guys,

I've had a problem with my car where the charge light is coming on as the revs increase. I figured it was a faulty voltage regulator (did one brief test and the battery was being charged at like 16V at high revs, ****!) so I bought one from the states a few weeks ago (paid a fair bit in freight) and just realised it's a slightly different part number. It's a TRANSPO 92991 (http://www.ebay.com/itm/310713254382?item=310713254382&viewitem=&sspagenam e=ADME:X:RTQ:MOTORS:1123&vxp=mtr listed to suit a '75 911S), and I have in the car a TRANSPO IP1903 in the car that I only installed less than 2yrs ago!? I barely drive the thing, too.

They look identical, but the new 92991 has two wires, the one in the car only has one.

Does anyone know if this will work? What is the second wire for? There is no terminal on the RHS like there is on the LHS.

http://forums.pelicanparts.com/uploa...1420618128.jpg

Appreciate your input. I can't find anyone selling these things locally and taking into account the postage, this was moderately pricey.

The car is a '75 911S Targa with an '81 3.0L SC motor swap, the alternator is PARIS-RHONE and this regulator is obviously internal.

The new VR looks to be for the larger Carrera alternator.
Bruce

Physically it's the same, but yeah it has that second wire.

How many darn alternators did these cars come with?

Well I managed to source the correct Voltage Regulator - the Transpo IP1903 with only one wire (please contact me if anyone wants to buy the IP2700 cheaply; my loss is your gain haha).

I fitted this new voltage regulator up and the problem remains unchanged.

Rev it up above idle, the red light on the dash comes on brighter and brighter. 3500rpm reads about 16V across the battery terminals - no good!!!

What on earth should I be checking? Some kind of signal/reference wire going to part of the alternator?

Look forward to your input :)

Diodes in the alternator may have failed. Have it tested at a rebuild shop.

should he be able to see some AC ripple on the 12v if this is the case ?

if so OP put your VM on AC and tell us what you see ?

Thanks guys, so put the meter across the battery on AC Volts, and if there's a reading, that is indicative of the diodes not doing their job?

pull the diode blocks off the alternator and test each one. You should have a diode function on your testor that will allow you to forward and reverse bias them. if they pass current in each direction or are open then they are bad.

Thanks wolds. I went to diagnose this the other day with my friend and the problem went away after about 20sec of running. I then drove it on about three 30 min trips and it was fine until half way through the third trip, the problem recurred.

Does that still sound like I should be pulling the alternator to check the diodes?

Regards.