'84 Z28 : Replaced the Alternator and still won't start.

First of all an alternator has nothing to do with starting your car. You need to understand this. What the alternator does is it replaces the power used out of your battery for starting purposes and for other electrical needs of the car. First of all your car needs to be running for the alternator to work and to also test it on your own. You are relying to much on your gauges to tell you something about your battery and the only thing that amp gauges is really going to tell you is if your alternator is putting a charge back into your battery and that is only going to happen with the car running. Now as I have suggested to anyone who wants to work on their own car. First of all you must own your own battery charger. Go out and get yourself at least a 10 amp charger. This way you have a means at your home to put a charge back into your battery especially when running it down if your car doesn't want to start. This is very important in freezing weather because if your battery runs down to much your electrolyte (Battery Acid) in the battery will turn to water, thus freezing and cracking the inner lead plates of the battery making for a junk battery. Makes no difference whether your battery is new or old. If it freezes because of lack of charge you will never be able to charge it. At that point it will not accept a charge. The other tool one needs especially in your case is a Milton #1260 type of battery testor. A testor of this type has a load feature, a 10 second test done on your battery putting an electrical load to it. In this test you will know if your battery is good or bad and if the battery will start a car. Both these tools are worth their weight in gold and with them you will not fall into the same trap most people do of buying a new battery for no reason. Being in the auto parts business 29 years I have seen people throw away good batteries for no reason. Actually there was a reason, these people played the guessing game only to go home and find they still had the same problem with the new battery going dead on them.

Now in your case you must start out with a good fully charged battery first of all to try starting your car. If the battery does the trick and the car starts and continues to run and idle at that point I would hook the 2 cables from the Milton style tester to read if the battery is charging. The Milton testor makes it easy. Its gauge scale is color coded. At this point if the needle is in the green charging area you would know your alternator was in good shape.

On another scenario if your car doesn't want to start with the fully charged battery. I would first check for spark. They make another little tool that looks like a short spark plug with sparkplug wire combined. The tool is cheap. I keep one in almost all my vehicles. With this tool you disconnect a spark plug wire and put this tool in between the spark plug and the wire you just disconnected. You then turn the car over and see if the tools light comes on. It will light up if you have spark going to the engine. If you don't have spark I would next suspect the ignition control module in the distributor of your car. These modules do go bad. Sometimes these modules will still work at some point to get your car running only to fail on you once on the road. This could also be the problem you are having since your car stalled on the side of the road but without seeing the car for myself to put my hands on it is just a guess here. There are also fuel problems to consider here. If you have good spark it could be you need a new fuel filter.
Question: How long has it been since the ignition cap and rotor were changed? I have seen where some of these cars had a bad rotor or cap. They should be changed at no more then 20,000 miles. Hope this info helps you. Let us know.

Fred