Alternator problems

[Canadian dave 4]

I'm having alternator troubles with my mi16 swapped 1991 205 GTI.

Initial problems was with it not charging well as I was driving down the road. Upon first start up I would get around 14 volts, once I was out and driving this would drop down to a pretty constant 12.6 volts. Let it idle for a while and it would come back up to 13.5volts.

I figure the alternator has a problem so I take it to a reputable alternator/ starter repair shop. (Not to many off the shelf options here in canada). On there test bench they say they are getting zero output from the alternator. So they rebuild it with new slip rings, voltage regulator and rectifier.

I put it back in the car and start it. Now the battery light is on constantly, no charging at idle. At 2000rpm I have around 14 volts. At 3000rpm I have 15.5 volts.

Any thoughts? I have rewired alot of the car as it is a hill climb and track car, but I have checked the isolator switch and the grounds to the battery. The battery is a sealed odyssey battery located under the passenger seat. I will be calling the repair shop, but they dont open for another couple of hours. Surpose to be racing at a hill climb this weekend, so time is of the essence.

Thanks dave.

 

 

[DamirGTI 342]

Overcharging is usually voltage regulator problem .. it's either bad regulator as new/replacement item . or something went wrong during the rebuild .

 

Fix it as asap as overcharging is no good for battery life nor electrical system .

Can try to order another voltage regulator and fit it by yourself , it's literary 5min. job . And see what happens ....

 

Quite a few other alternators will fit as well (though , some need minor tweak in order to fit) .. from other newer/bigger XU petrol and XU diesel powered PSA cars (Peugeot/Citroen) .

 

D

[SRDT 175]

This is not the right alternator for a XU9J4, it should be a 1200W 80A Mitsubishi unit.

Quote

FOR XU9J4 , AT THE TIME OF ALTERNATOR
 REPLACEMENT , PUT ON IMPERATIVELY 1200W
 5705 A0 

Other manufacturers can have aftermarket parts that fit but your 70A Valeo unit looks suspicious.

[Canadian dave 4]

Got it sorted. One of insulators the repair shop used failed and caused an internal short. All now working.

Thanks for the suggestions guys.