Have an 84' w/new battery, but have to jump to start, but when removing the jumper cables the car stalls immediately. I assume it's an alternator issue? Need to get it running to take to my mechanic (dont want to have to tow it). I am a novice so any advice is appreciated.

 

Charge/replace the battery.

 

I agree. Battery may be new, but it may be discharged or defective. You may also have an alternator issue, since the car should run with even a pretty weak battery, once started. Basically, you need either a good battery or a good alternator for the car to run, once jumpstarted.
Good luck,
Dave

 

With a new battery the car should start regardless of the condition of the alternator. Check the voltage of the battery, it should be above 12.4v (that is 80% charged).

Your battery ground strap is probably corroded. What is the voltage reading from the jump post under the hood? If there is a difference in readings between the battery and jump post you need a new ground strap or at least try cleaning the rear connection behind the tool kit. There is also an engine to chassis ground strap to check.

 

That makes a lot of sense, Alex. When you jump start a 928, you probably use the jump post and a chassis ground in the engine compartment. That would bypass a bad ground strap back at the battery. OTOH, once started the alternator should really keep the car running, even without a battery (not good for alternator).
Good luck,
Dave

 

You may also want to look at the power wire between the alternator and the jump post. this wire carries both the battery and alternator power to the Central Electric Panel. If this wire is bad you would be running off the jumping battery during start and run, then when the exterior battery is disconnected you would lose power to the fuse/relay panel and car would die.

how do the electric act aside from the start and run issue? without the car being jumped do the lights work? power seats, windows, sunroof... move?