Jump to content
Email-only Log-Ins Coming in December ×

  • entry
    1
  • comments
    3
  • views
    3,158

Alternator Issue


Guy Mayer

1,965 views

So i have a 1978 280Z and im having an issue with my alternator. Im not actually sure what the problem is.... Ive had my alternator rebuilt and tested. Ive also had my battery replaced and tested. Both work, but the alternator is still not charging the battery. Once the car is started it will run, but as soon as I cut it off and try and restart it... the battery is dead. So it must be a wiring issue, but im just wondering if this has happened to anyone els.... if so, What is the problem???:mad::mad:

3 Comments


Recommended Comments

I like to do my own testing of equipment. So I have a battery load tester and a very good digital volt ohm meter. Sometimes those auto parts stores don't know what they're doing. If you check the voltage at the + terminal of the alt. While it's running should be above 14v at around 2000rpm. If that checks out and don't have at least 14v at the battery, then your issue is a wiring or if u have a voltage regulator between the altternator and battery.

Just for kicks, if you check the voltage at the alternator, put the meter to AC to check the ripple current. It should be less than 500mv in my experience.This makes sure the bridge rectifier is doing its job converting a sine wave to square for dc voltage.

I'm not an electrical engineer so this is just from experience not education.

  • Like 1
Link to comment

If the battery is really dead, I would recommend providing it a full charge with a battery charger. Alternators are really designed to maintain a charge, but not actually charge a dead battery.  I just went th.rough this with my son's 2001 VW Jetta

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Blog Statistics

    • Total Blogs
      167
    • Total Entries
      251
  • Blog Comments

    • I'm still waiting on a hoist to free up before I can start bolting the new brake parts on my Z, but I did make the drill jig today.  I started with a 12mm thick Mustang wheel spacer with a pilot.  I then made a drawing to layout the holes needed.  I transfered the drawing onto the spacer and I drilled three new 1/8" holes through the jig (spacer) so I'd have the correct 4x114.3mm holes.  One hole is shared from the original 5 lug rotor.  I then bolted the jig onto the Mustang rotor and simply dr
    • Local radiator repair shops used to be plentiful but getting harder to find.  Some of them just specialize in big truck-heavy equipment radiators.  I will be needing to do the same for my project.  I have heard good reports on gas tank RENU but there are none of those franchises in my area.  Good luck, John-Lugoff, SC
    • Decided to go with the 240sx conversion. Main reason is it’s strictly for the street and the parts were easy to source. What I didn’t realize was the 14” wheels won’t clear the caliper. Now looking for a set of 4 lug 15” rims and tires I can use during the build process. Can anyone recommend a temporary solution as far as make and model preferably a steel wheel that I can use until I’m ready to buy the wheel and tire combination at the end of the project? Thanks again for all the help out there.
    • There are several reasons to use the S197 rear brakes.  The rotors are larger diameter than the SVO rotors and they are vented.  The calipers have larger pistons to give them more power.  The big beef with the Maxima rears is that they don't offer as much stopping power as the stock drums.  The S197 rears allow the addition of an adjustable proportioning valve.  The Maxima rears cannot utilize an adjustable prop since the prop needs to be all the way open to get close to enough rear bias. 
    • Any particular reason to use S197 Mustang 5-lug brakes?  The Fox body SVO Mustangs had rear discs with 4-lug.  It's a popular swap to use SVO or T-bird Turbo Coupe rear brakes to retrofit discs to other Fox body Mustangs.  These parts are still pretty common (probably available as a kit).  Might be worth checking to see if they'll fit.
×
×
  • Create New...

Important Information

By using this site, you agree to our Privacy Policy and Guidelines. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.