nosensemazdadriver

K, last time everyone here was a great help so I thought I'd try again. I got my 79 runnin and took her for a short spin last week, drove fine with no jumper box, but did not charge the battery, from a bad terminal connection I believe. Anyway, started it up today but would die as soon as I take the jumper box off. Took the obviously problematic alternator down, had it tested and it tested good, it is pretty new. Double checked all the connections and good stuff but still no charge to run the car on. What next?

kgray

was the battery tested good? Check the grounds on the battery cable. Are you sure it isnt a fuel issue?

1badFB

iTrader: (1)

Yes, X2 on the grounds..They can be a pain to track down.

Usually if Im having an electrical problem, I always start with the ground. An easy way to test if the ground is problematic is to clean up the negative battery post / connector real good, get out a set of jumper cables and put one end on the battery. Take the other end and clamp it to whatevers causing your problem (in this case clamp it on the alt. body or the tensioning part). I sometimes like to use the other clamp as well just to the body, but its a start. If its not the ground its the hot side/ other wiring!

Rx-7Doctor

iTrader: (13)

What are you refeering to as a jumper box?

ratboy

iTrader: (1)

If you havent already I would replace all of your grounds and battery cables. I dont know if 79s have the same crappy cables that my 85 had but when I cut off some insulation they were corroded a good 18" from the terminals.

vipernicus42

iTrader: (4)

New battery cables aren't hard to make and aren't very expensive. The materials can be had from almost any local autoparts place.

Your +ve wire goes from the battery + terminal to the starter solonoid, and has a small offshoot going to the fusible link box.
Your -ve wire goes from the battery - terminal to the strut tower, then from the strut tower to a bolt on the back of the engine block.

I did the -ve wire in two lengths because it was easier that way.

If you replace the battery cables and you still have a problem, try grabbing the battery from another car. See if it gives you problems. If you haven't had your battery charged (at least overnight on a 3V float-switch slow charger is best) and tested, do that.

Once the cables and battery are ruled out, get out your multimeter and check the drain at the fusibles, see how much power your car is taking when everything electrical is off.

Electrical gremlins are the worst. I still have a slow drain on my battery that I've yet to track down. All I know is that it's probably somewhere on the main fusible, but I have no idea where.

Jon

Jason Guthrie

When you did your replacement, what did you use for part#/brand of wire (custom, generic) and with the (-) did you have all 3 mounting locations or did you just mount to the engine at the end of the wire? My (-) is attached at 3 locations, the shock tower, a bit further down, and at the back of the engine. I'm not sure I can get a direct replacement. The (+) is just as bad with its multiple connections at the Fusible Links and the Starter.

nosensemazdadriver

Its just a little rechargable box with jumper cables coming off of it to jump a car with. I appreciate all the input, but I'm getting good power off of thath box hooked to the battery, till I pull it off, doesnt that tell me everything after the battery is ok. I just cant get good charging power from the alt to the battery or rest of the car. Thanks fo r all the input.

RXnos1200

iTrader: (24)

Have the battery load tested.

j9fd3s

iTrader: (3)

this is dumb. if its a 79 the regulator is EXTERNAL, its on the fender. could that be bad? alt would test good, as would everything else....

RXnos1200

iTrader: (24)

^^^^^^ good point.

kgray

the SA's have an external voltage regulator. thinking back mine went out and needed replacement. i would look around for a newer alt. with the internal regulator plus the extra voltage they put out compared to the stock SA