I have a 2004, and I recently changed the plug, etc. When ever I get over 3500 rpms my alternator light comes on, I changed it and it still happens any idea what it may be? It also has a new battery.

 

Can someone please help me... My husband won't take it to a dealer.. I love my RX8, and he wants to sell it. He says that it has too many issues. PLEASE HELP!!!

 

do you mean you changed the alternator? why did you change the alternator?

 

It went out, so we had to put in a new one.

 

So first suggestion would be to take the car to Autozone and have them check to see if any fault codes are being registered on your 8's computer. If so, copy the codes down and report them back here.

Second is to check and make sure you have good battery contacts on both the positive and negative posts of the battery - may not have been seated/tightened properly when installed.

Third is to do a search here https://www.rx8club.com/forumdisplay.php?f=95 by using the "Search this forum" drop down in the upper right corner of the screen and enter something like "test alternator". You will find a number of threads discussing how other folks have investigated charging system problems on their vehicles. Check to see that your holding a solid 14v or better when you rev the engine above 3500 rpm line that your seeing issues at. Try this with also with extra electrical load on the charging system by turning on headlights, radio, etc.

Write back and let us know what additional info you gather.

 

well it sounds to me like you have another bad alternator or a bad battery. if its the alternator and you just had it changed you have either gotten a lemon or there is another problem like a over tightened belt.

the over tightened belt will normally just wear it self out before hurting the alt but.....

can you tell us what led you to replace the other alternator- what do you mean by "it went out" ? details please.

 

Make sure the belt is properly tensioned. What is the charging system voltage when the light comes on?

 

Took my 8 to a mazda guy and he checked everything out. I had a broken vacuum hose. My alt. checked out and my battery is good. She drove great on the way home!!! Thanks for the help. You guys are great!!! There's just not many people out there that knows about rotary's and no one even wants to try and help. This website is GREAT!!!!! Thank you...