eltrical problems please help

[pauly_adams]

hey all i have a eletrical problem more or less its like a short but im starting to think its the alternator is stuffed. i was driving home tonight and it started backfiring missing etc and then finaly after i lossed all my lights and other eletrics it just died and the batery had no juice what so ever can any one confirm this problem or know what it is from experience

 

cheers pauly

[Zeddophile]

Could definitely be alternator, I've had a similar thing happen to me with a dead alternator on a carby car.  EFI cars are more likely to just stop dead, but the only electricity required to run a carby car is the power to the coil, so when you have lights etc draining the battery and the alternator isn't charging, the voltage at the coil drops causing the coil not to charge fully between sparks, causing the misfires.

 

Dead battery and lights dropping out before complete stoppage would back it up, so charge the battery up off a charger, then start the car and see what the alternator is putting out - should be absolute dead minimum of 13 volts at slow idle, and preferably in the 13.5 to 14 range, although some cars won't output that until the revs are brought up a bit.

[mayhem]

where do you live .... im an auto elec have been for 7 years got my own shop in hallam

[pauly_adams]

I live in albury ill be pulling the alternator out of my other z to see if it fixes it if not ill be quite anoyed but anyway and I'm running a carby not efi

[warrenz]

What was the ammeter showing before everything died?

If the alternator was not charging you should have been able to see the needle to the left of 0 (-) ie draining power. Normally after you start the engine the ammeter will go right of 0 (+) for a while showing a charge going into the battery after the power used in the initial start. This is usually a good guide as to whether the alternator is doing its job.

 

Warren

[pauly_adams]

the needle was all over the place it would go to nothing then right to 16v then would mellow out and seem to be charging fine but i would say it is stuffed because the exact same thing happerned to my brothers 300zx thats y i realy do think its the alternator anyway tomorw will tell all as im going to be removing the 1 from my other z and if works a new i will get another for my second z

 

cheers pauly

[Zeddophile]

the needle was all over the place it would go to nothing then right to 16v then would mellow out and seem to be charging fine

 

That would probably indicate the voltage regulator has packed up and gone on holiday... can't remember if thats separate on a Z alternator or not?

[gilltech]

Sounds like the alternator - I had a sudden failure on mine - halfway into a 30km night drive returning home; engine started mis-firing slightly over a few hundred metres (I suspected fuel problems so played with the choke lever which helped initially), then it cut out totally, & all lights went dead. I was in the RH lane but luckily had enough momentum on in neutral to swerve across the other lanes (& avoid other cars) & run the old girl up on the LH embankment to safety. The RH lane of the motorway at night would not be a good place to be stopped with no emergency verge to pull over into, & no lighting at all as had no power left & the motorway itself is poorly lit. Next car along & I'd be in serious trouble, just bound to get hit up the arse. Sudden & scary, happened quickly. Problem? Alternator had failed totally, so car had been running on the battery until that ran down. Nothing visible externally, only warning was the mis-firing. So after a tow-truck got me home I traded the alternator in on a replacement & went for a slightly higher output model while I was at it. I'll never forget that close call. Or forgive motorway designers who neglect to provide emergency stopping lanes on both sides. So have your alternator tested for peace of mind, if nothing else; they're getting old.

[HELLFIRE!]

One other thing might be to check the wiring coming from the alternator to the battery. This may not be the initial cause of your problem but it wouldn't help if you are loosing charge between your alt and battery. Also the wiring is cheaper than the alt to fix/repair.

[pauly_adams]

was the alternator changed it and i ran great no misses or anything i also cheaked the wiring andit had a crack in it but i fixed it prior to the problem wif my alternator, as for the regulator mine was external and it took me a while to figure out why my new alternator was'nt charging, it was due to it having a built in regulator so having two was a real problem so thats one thing to check if your changing you alternator after that was done the z lives

 

thanks for all you help cheers pauly