Greetings! Having some issues with my car that i cant seem to figure out (or maybe I have not sure). Vehicle is a 2007 C6 Corvette Convertible Base. Manual Transmission 6.0 Liter LS2 V8, 46k miles. Been having an issue recently with the alternator cutting out at around 4000 rpms. Will drop from 14.6v down to the 9-11 range. As soon as Rpms return to normal cruise range, voltage returns to normal 14+ zone. Took it to the shop, put a new alternator in, same problem. Rebuilt the old alternator, same problem. Changed the belts and put on new belt tensioner, and new battery. Same problem. Went through every single connector, ground, and wire from the alternator to battery to bcm to ecm. All clean no corrosion and good connection. And you guessed it, same problem. Cant seem to figure this out. Only thing i noticed this morning while driving was my power steering was whining. Checked the fluid levels and they were bone empty. Filled it up and good to go on that. So my question is, can a power steering leak cause an alternator problem as mentioned? Only at high Rpms? I dont think its belt slippage because the belts look good and dont look wet or damp. Mind you, power steering reservoir is situated next to the alternator. There was some fluid on or near the alternator when i took it to the shop. They couldnt figure out problem either. Anyone else experience odd alternator behavior such as this assuming its not a fluid leak from the power steering. Or am i getting close by thinking its power steering fluid causing this fluctuation in voltage? Does the pressure in the power steering unit increase in relation to Rpms? Sorry for the long post. But i feel like some background info was necessary. Any advice tips, tricks, or guidance on this is would be greatly appreciated.
And i forgot to mention. No codes are being thrown during this phenomenon, just the dash message to service charge system with no associated code.
alternator cutting out at around 4000 rpms
That could be self regulation. A good OBD tool might tell you what voltage or charge mode is being commanded by the PCM.
Will drop from 14.6v down to the 9-11 range.
That is very strange. It should not drop that low. Even if the alternator quit completely, a healthy battery should have 12.7V. Where did you measure this?
Maybe the alternator is causing a short, or...
Did you check continuity on the alternator fusible link?
Yes definitel very strange. I checked the voltage measurements at the battery, the alternator, as well as the ecm and bcm.
Everything checks out good. All wiring is in tip top shape. Though i havent ran a really good scan on it as i dont have a scanner to do it myself. Which leads to me wondering that at high rpms, the power steering leak is spewing fluid on the alternator causing it to short . Which begs the question does the power steering pump increase its pressure at high rpms and only at high rpms. Reason i ask is, at normal cruise rpms i dont get the voltage fluctuation and perhaps its because whatever pressure in the lines isnt enough to make the leak spray all over the place. Can fluid cause such a short in the alternator? Im at a loss of ideas.
So when it cut out, you measured 9V on the alternator AND battery... Well that's either a dud battery or an electrical short.
Oil is normally an insulator, but maybe you should just fix your power steering and then see what happens.