car overheating and high battery voltage

[dsm22443]

first off im sorry if im putting this in the wrong area im running low on ideas and need a solution fast.
i recently had custom turbo conversion done. tubular manifold, downpipe, atmospheric o2 dump, high flow cat, full exhaust, wastgate, blow off valve, fmic, sfmu wally 255hp. the whole shebang. only thing left is to finish my build on a motor i have sitting around.
my problem now lies with my battery voltage is spikeing from 13.5-13.8 at idel to around 16.6. when it does this my charging light comes on and my car runs hot quick. but it is intemittent. i drove 52 miles earlier today fine, pulled into my parents driveway to check their mail box and when i got back in the car the temps were 3/4 or higher on the temp gauge. my battery is maybe a year old and its a optima red top. i upgraded my radiator from its original 1 core to a two core. i have limited space to work with due to the header.
what i need is help fast, this is my dd and im handy with tools. im already plannig on rechecking the volts on the battery when off and on, and checking volts at the alternator. but in the mean time any suggestions and any help is greatly appriciated.

 

[turbodude]

Sounds like a voltage regulator problem.

Here's a link to a thread of someone with a simmilar problem:

http://www.dsmtuners.com/forums/420a-bolt-tech/414191-battery-light-overheating.html

 

[bullettdsm]

Yup, first thing to do is stop driving it. You may have already burnt up some things, but if you keep driving you definitely will. A couple of years ago I bought a car that the previous owner couldn't fix. The problem was the regulator went and burnt up a bunch of stuff.

Our regulators are in the ECU. So in order to fix it, you will either have to get a new ECU or set up an external regulator.

Don't worry about the overheat right now, you gotta fix the spike first and then see if its just gauges or actual over heat.

MB

 

[NeMiZiS]

Change your alternator, I just went through the same thing.
I spend 300 on a new ECU, put it in last Friday.
Still had the same problem.
I ended up swapping in a used alternator and it is now back at 14.00.
The alternator I took out was only 3 months old, it must been overcharging right out of the box.
I recommend pulling of the lower alternator bracket and dropping it out through the bottom.
It is the easiest way I've found to remove the alternator.

From what I've researched your car probably isn't over heating, mine wasn't.
The high voltage freaks out the ECU.

 

[dsm22443]

like i said its sparatic. iv driven the last few days since the posting and no problems with spikes or overheating. seems normal till today my speedo freaks out and now wont move off zero when im doing around 60. im gunna drive it as is. in a few months im putting in a built motor and having a standalone made and tuned so i will put a new alterntor on then.