Hi I have an 86 Z28. I have replaced the alternator, batt, and cables. The car will start and run fine with a jump but as soon as your take the cables off the car looses about 0.2 volts a second and eventually dies after about 5 mins. I am at wits end and have no clue why this car is doing this. The car is completely stock. Please help me out.

 

I forgot to add... Is it possible that when installing the alternator I created a bad ground somehow and thats why the car isn't holding a charge?

 

your gonna need to look at some voltages. your battery should hold around 12 volts, does it discharge in a similar fashion with ignition off and car just sitting there?? if you do have a ground thats causing this kind of discharge you should be poppin a fuse or fusible link. a good battery should hold enough juice to let a car run for many hours if the alternater has failed. once the car is running rev it up to 1500 rpm or so, do we have 14 volts or so?? if not then the alt. is not doing its job( fusible links by starter, bad alternator, wiring, hookup) have you had the battery tested?? ive seen lots of the cheaper versions bad right from the store( exide brands, shucks, eveready) personally interstate batteries are the way to go, check the things ive mentioned and get back to me kurt

 

kURT THANK YOU I have had this post on many different forums and you gave me the best answer. When I rev the engine the alt does nothing.. So I figured I got a bad one because it was from advance auto parts. So last night I went to the store and they gave me the wrong one! They gave me an alt with 78amps when I needed one with 98!! Lesson learned they didn't have it in stock so Im getting it monday and hopefully it works.

 

kyle dont count on this fixing your problem UNLESS the first alternator was bad. all alternators that are designed to fit specific models or brands of cars will work regardless of rated output, in other words it should have been producing 14 volts or so but may not have kept up on the amps if you had all the lights, fan, ac, stereo etc. on. even if the alt was bad it still doesnt sound like your battery has the reserve capacity it should so id make sure its fully charged and or get it tested by someone other than the auto parts store that sold it to you. auto parts chain stores are not known for thier quality on most of the parts they sell and this includes batteries and alternators, and likewise for the people who work there and thier ability to test that which they sell so id leave the testing to a more reputable local shop. now is a good time to establish a good relationship with a smaller reputable local shop as these people will often do this kind of testing for free in hopes of getting your return business

dont forget to check your fusible links by the starter or maybe firewall as these should be for the charging system on your model (if i remember right) follow the large red wire coming off the alternator to find these. if these are blown you will get no charging. keep me informed kurt

 

Kurt my batt is fine because I even put the batt from my 94 firebird in it and the same power loss happened. I checked the fusible links by the starter and they were good. As for the fusible links coming off the alt Im not sure what you mean. There are three wires of my alt. One goes from the back to the pos side of the batt. The other two I believe powers the internal voltage reg. Do you know where these two wires end up?

 

[8D] you should have 3 wires coming from your alt. the largest should be red coming off the terminal on the back of the alt and going to the battery( this is usually via the starter solenoid and a fusible link not a direct wire to the battery) the other two wires should be connected at a plug and the small one goes to the charge light on the dash and the larger of the two is a keyed power source so check to see that your charge light or gauge works and that the larger of the two wires has power when you turn the key on. have you checked all your fuses?? is there anything else on the car that doesnt work??

 

The choke light is on, Ive been doing some research and I think my choke relay might be bad. The rear defroster doesnt work because the metal strip that was glued to the window is gone. I thought maybe this was the reason why power was draining so I disconnected all wires to it but still have a problem.

 

[&:] in some cases they have run a choke wire off the alternator and this could certainly cause a battery drain. id have to see schematics to be sure in your situation. id start looking in this area to eliminate it as a possibility. is the wiring all butchered in the engine compartment or does it stock?? no butt connectors, splices, backyard looking stuff??

 

I checked them they look fine. However there is some gray wires that goe 3 to 1 soldiered connection. Does this fusible link look bad?