Voltage reading on 930 Turbo
 

What is the correct Voltage reading on 930 Turbo?? I tested mine last week and it was only reading 12.5V at idle, 11.7V when headlight is on so i went ahead and replace the alternator but the voltage reading is still around 12.9V and 12.5V when the headlight is on. Can anyone tell me if this is normal? Correct me if i am wrong, i thought the voltage reading should exceed 13V, My 993 Turbo reads 13.8 at idle.

Thanks
Albert

What are you using to read the voltage?

still too low. clean all the main ground points, and be sure the battery clamps are clean and tight. 13.8 to 14.2 is normal.

I used a voltmeter

Does it matter if its a BOSCH or Valeo Alternator? because i can only source a Valeo Alternator for now and it is brand new, is there any reference for factory ground points? because i just bought the car 3 weeks ago.

Thanks
Albert

No. Brand doesn't change the fact that it's too LOW.

I installed a Valeo V reg on an 89 930 three weeks ago. The voltage read 13.93 plus or minus about one-hundreth of a volt.

+1 on alt brand not mattering.

Sounds like you need a v reg and not an alternator. $60

clean the ground where the negative battery cable attaches to the body. the other important ground is a strap between the end of the trans and the body. sand the contact areas clean and use new fasteners and washers. dielectric grease helps to keep corrosion from reforming.
then recheck. check it at 2500 RPM. idle may not show as much.

Thanks alot guys, i will check the ground first thing in the morning, do i still need a new V regulator? I thought it comes with it when buying a new Alternator. one more question is do we have 3 connection or 4 connection on the alternator because i only see 3 connection on my car.

Thanks

John,
Does it matter if i am using MSD 6AL?

Shouldn't.....check all the grounds as suggested.

12.5 at rest, 13 at idle and 13.5-14.5 at 2500 rpms. If not it's the alternator or the regulator about to go south....or both.

The problem is i just replaced a brand new Valeo Alternator.

They've been known to fail out of the box......check the grounds.

a diode may be kaput. Why not have store or electric shop test it. It's usually free.

What year is your turbo? Porsche switched to attached v regs in 82 or 83. They are external before that.