ok so my car ran great for the past 5 months, last week i was driving and noticed the dash lights flicker on and off real fast, didnt think much of it so i went home. the next morning i had only 12 volts insted of like 13 or 14 on the guage, i put an alternator from an 83 in my car and it was good again until yesterday, i was on the highway and my car just died, would not start back up but would crank, checked and i had no fuel comming to my carb, i ended up wireing directly to the battery for the pump and it started up but with 12 volts again, i baught a brand new alternator today and just put it in and it still dose not go above 12 volts and when the positive terminal is pulled it dies out, i have no clue what is going on please help, btw when the 83 alternator was in it ran fine and positive terminal was taken off and it still ran and im thinking the the fuel pump runs off a 12 volt signal from the alternator so thats why it died on my yesterday while driving and worked when bypassed.....

what would make a brand new alternator not charge the system? on a gsl

 

1) battery cables must be clean and tight

2) ground point connections, especially the ones on the left shock tower and the starter, must be clean and tight

3) alternator connections must likewise be clean and tight.

4) underdash ground points (find them on the wiring diagram) must be clean and tight.

In other words, this has all the symptoms of a bad ground, or a loose connection, somewhere... especially the 'flickering lights' part. Other possibilities include a battery very low on acid, or with a shorted cell.

 

You didn't mention your battery. You can have it and your alternator checked at many local parts stores for free.

 

Probably the best thing that any 7 owner can do to prevent future headaches is to replace both battery cables. The ones Mazda used are crap, and tend to corrode internally so that no matter how clean the connections are you still have issues.

 

ok the battery cables are a possability but my car accepts a battery and cranks and runs off of the battery until it dies but my fuel pump circuit is out and not giving any power to the stock connector under the storage bin, and also my car will not run when the positive terminal is taken off, so are you talking about the wire that runs from the alternator that is labled B. ??

also what could have happened that would make my fuel pump not get any power

 

Check the fuse labeled "meter" (this runs the fuel pump).

A bad connection at the starter can result in under or over charging. If those connections are good, check the rest of your fuses then start checking wiring....

 

ok bump... i checked the fuses and the one labled engine blew. i put a new 20 amp in and it runs fine but just now i was sliding around some cones in the rain and like when it blew the first time it only dose when im pushing the car i looked down after sloleming and i had 12 volts then it ran out of fuel in the bowls, popped a new fuse in and drove home.. what could be popping the 20 amp under load conditions?

 

I would check resistance to ground at the fuel pump negative as well as near the fuse block in the cabin... Still sounds like wiring. If you're dead set against checking the wiring you can bridge the fuse at the pannel and wait for something to catch on fire.

... At least then you'll know what the problem was, but again; grounds.

On a SA, does the engine fuse circuit also control the fuel pump? (related, do not wish to aggro new thread.)