My firebird wont start up when its hot outside sometimes , i have to hook my jumper cables on the battery and put the positive cable on this purple wire just to start up and its off and on! Anyone know whats causing this?????????

 

If you know how to use a multimeter or are willing to learn, the best thing to do would be to get a GM factory service manual set for your year/model vehicle.

As vehicles get more and more complex electrically, a lot of testing is involved to find the exact problem.

The factory service manual set will give detailed testing procedures for each problem, tell you what the test results should be, then say what to check/do next based on the results.

You can order a factory service manual set at a GM dealer or here...
http://www.helminc.com

Other than the above, you can check the battery to be sure it has 12 something volts with the ignition on. This would indicate it has a good charge.

Then it should read around 13/14 volts after starting and the alternator is charging it.

Then check the battery cable connections to be sure they are clean and snug.

Check the main electrical cables at the other ends to be sure the connections are clean and snug. This includes a main ground wire to the body and engine block.

Here is information on testing the starter...
http://www.google.com/search?hl=en&s...h&aq=f&oq=&aqi=

 

thanks