Alternator the key issue/problem?

[PRINCESS LEAH]

850 GLT 1993. THIS CAR!!! ( a bit of a story here, sorry)

Okay. Since we bought this car used in November the engine light (orange with green triangle in the middle) was on, but it ran fine. Even the manual says the car may run fine with the engine light on. We took it to mechanics before we bought it and they only site confirmed the oil leak as a "minor" problem, and the rest of the car looked fine. We've had an oil leak, a minor one said the vendor (which turned out to be false). I also let the oil get pretty low in the winter (i've never had a car with an oil leak and underestimated the flow) but it didn't cease or stall or anything. The leak turned out to be from the head gasket. Before that work was done (and after I topped up the oil) the car stalled a couple of times. I had the fuel filter replaced, oil changed and it ran well for a couple of weeks until the parts came in for the head gasket.

Once that major work was done it ran beautifully for about 3 months and the leak was and still is totally gone. However, there was a bit of a whine to the motor. Mechanic said it was the power steering pump and we planned to get that replaced. It did stall a couple of times closer to the end of the three months.

Now it is virtually undriveable. The car stalls when coming to a stop. It revs in pulses from 300 to 1000rpm when it idles. It doesn't have acceleration once the engine warms up. It takes 10-15 seconds for the engine to respond to the gas pedal and has stalled while trying to accelerate.

So the mechanic (a different one because the first one just can't figure out whats really wrong) says its the alternator, which is has a diode out, and it needs replacing. Do these need replacing? Can't you just replace the diode?

He says that in order to get proper diagnostic readings from the onboard computer, the alternator has to be running consistent voltage.

Should I buck up and get this alternator replaced? Is that going to fix the car or is that just going to unvail another series of repairs? Is there another way to find out what the other series of repairs might be WITHOUT replacing the alternator?

I am on the verge of walking away from this vehicle because of the repair bills it looks like we're faced with. Can anyone please enlighten me on whether I need to spend 600CDN + on a new alternator just to find out what the rest of the problems are?

thanks much

[TheMan5952]

See if there is a Junk yard wher you can get a used alternator from for cheap. If you don't want to do that, start the car and put a voltage meter (multimeter) on the battery posts while it's running. it should read 14.7 volts while the engine is running, if it's much lower than that (say 13.7 or lower) then get a new one.

Do you have dimming lights or anything when it's running? You can start the car and take off the battery cable and if ti keeps running the alternator is good also.

You said you had your fuel filter changed and it ran good, but the problem came up again, have you had your injectors cleaned or the fuel pump replaced, this could be a cause of the problem also if the alternatorr checks good.

[PRINCESS LEAH]

Thanks for the reply.

We ended up taking the car to the Volvo Dealership because we just didn't trust that it was the alternator.
Turns out the insulation on some wiring running through the intake manifold had become very brittle and was cracked in some places. This was apparently what was causing all of the codes to come up on the onboard computer for the other mechanics. The shop replaced as much of the insulation on the wiring as they could without taking the intake manifold off. The car has been running just fine for a week now. No check engine lights on the dash. No stalls. Lots of power.

I will use your advice for the voltmeter though. Just out of curiosity more than anything.

[PRINCESS LEAH]

BTW, any idea what the whiney noise is? Is it the power steering pump? It increases in pitch with the speed of the car and is more noticeable at slow speeds like driving around a parking lot.