Alternator or vehicle fault?

[jwh]

My Saab 93 has developed a weird fault. Recently the Alternator died so i replaced it . All has been fine for a couple of months. Two days ago the display came up telling me the battery was not being charged. Checking under the bonnet all connections tight and belt intact. I turned off the engine and re-started. The warning display had gone and the car behaved itself untill the next day when the same thing happened. My question is. Is this the Alternator once more or is there a known fault for this model.I can't see that it would be the Alternator as in my experience they either work or they don't and the act of turning the engine off and re-starting again seemed to cure the fault be it for a short time. any suggestions would be welcome

 

[ronniecalcutta]

If there was a problem with the alternator, you would have faced problems with cranking, lights..possibly the Volt meter connection or coil has gone wrong or the ECU(in case of ECU reading the voltage) is producing faulty trouble codes which is giving you the signal.

 

[obi_waynne]

It could be a faulty battery or a loose connection. I've known some powerful ICE or spot light setups to cause the charge light to come on as they suck more power from the alternator than it can supply. In these cases you really need a power cap or more beefy alternator.

Did this happen with your air conditioning on?

 

[jwh]

The car has no extra's in regard to electrical power. The only upgrade is the Hirshe chip to increase the BHP.
The air con is running constantly as the vehicle has climate control.
In light of one of the comments made i intend to carry a multimeter so if and when the display shows no charge i can check the output of the alternator. one thing i did notice when fitting the replacement alternator is that it has a one way clutch and the vehicle produces a whine on occasions. I am now wondering if this could be part of the problem with the pulley driving the alternator intermitently. I will keep you posted as to what i find.
Thanks for the replies so far.

 

[jwh]

Finaly figured out what the problem is. The replacement alternator is only throwing out 12-12.5 volts at tickover when it should be producing 13-13.5. Once the battery voltage drops below a certain level it will trigger the no charge warning. The voltage does not rise when the engine speed is raised. You would expect a replacement to operate correctly but this one is obviously faulty. :embarrest:

 

[jarrus]

`Are you taking that one back?

it should still have a warranty on it, have you checked your battery though just in case it is that as well

 

[lutonmatt]

was it a new one or 2nd hand one

if i was you i would get a new one i have had 2 saab's in and both had 2nd hand alternators that i fitted and both went within a few weeks

and not being the best of things to do i will only go new now on saabs

 

[jwh]

It was a new one so it will be going back at the weekend. Already checked the battery.No problem there.
It's not a bad job to change. Although the haynes book of lies says you have to remove the o/s drive shaft and drop the alternator out that way you can in fact remove it from the top by moving some of the wiring looms to one side. When i fitted this one it took about 45 minutes. My pals at my local garage still refuse to beleive it can be done that way so this time i am going to take pictures to prove it can be done.

 

[obi_waynne]

Post the pics in here as well, I'm sure others would appreciate your "short cut method".

 

[deltamal]

Was having problems with mine, running the cooling fan and bottle heater was too much for the standard 36 amp alternator, died on the fire up lane at Shakey!:embarrest: fitted an 80 amp one, problem solved.....