As some of you know, I've been fighting electrical/charging problems with my car for the past year. Basically, I'm having a battery drain issue so my car can't be parked for more than 5-6 hours or the battery will drain. We had located it to the Alt S fuse which is basically the signal wire for the alternator to turn on. But we were totally unable to fix it, we've switched wires, checked relays, checked alternator, etc. All check out.

Well today, my car decided to take it up a step. I took it to my friend's shop to retune it at 9psi. It's been driving fine for a while now other than the charging issue which does not affect drivability. It drove there fine, we made about 30 dyno pulls, I ended up making 300whp and 314 ft/lbs with a clean A/F. I'm happy since the car is making power earlier than before and the curves are a lot flatter although peak power is the same. After leaving, I got on the highway, and made went full throttle. Car pulled really well, then BAM! At redline, during the shift, car lost all power. It basically cut out, then immediately restarted at 105mph. It happened so quickly that my friend and I both had to make sure we saw it. Then the car drove fine again, but about 3 miles down the road, I realize that the car is overheating. It's wisping smoke from my overflow catch can. We pull over and check it, and it turns out that the fans are no longer working even though we verified they were working on the dyno. We turn the heat on to open the heater core and find out that my blower fan is no longer working, nor are the power windows. That's when we realize we're having a problem.

After investigation, we found that I've blown the main 140amp battery fuse. None of the other fuses are blown, just the main one. We tested it and there's a huge short somewhere. Unfortunately, this short also drained the battery, and I had to call a tow truck. So now I'm stuck trying to find what would cause a massive short that would blow a 140 amp fuse. I checked the battery relocation wiring, and tomorrow I'll pull the fusebox and start tracing everything.

Does anyone have any ideas on where to start? I'm curious as to what would happen to cause a short while driving. We didn't hit anything, none of the exposed wires appear to be damaged, and the car drove fine until now. This has never happened before. And before I disassemble the car to find the problem, I'd like to see if anyone knows where to start.

On the bright side, at least the car is finally tuned and fast.

 

Something tells me you have a faulty alty.

 

I've suspected that, my problems seemed to get worse after I installed the 225 amp Can Am alternator only 8 months ago. But even before then, my car had charging problems and the alternator died, hence the Can Am replacement.

I guess I'll go pick up a stock alternator and find out. If it is the Can Am, I'm going to be upset. $400 for an alternator that barely even fit, and crappy customer service to boot. I called them a couple of times to voice my concern about perhaps their voltage regulator was bad, each time they told me that it couldn't be bad if the alternator was still working. I guess we'll see.

Is there anything I can do to check other than just swapping the alternator out?

 

i've heard bad rap about can am altys

 

Do you have underglows or any electronics that are not hooked up to a switch? I had a draining problem when a shop did not wire my underglows to a switch and wired the + to the radio harness for power. Needless to say, I had drain that I could not figure out until I took out the underglow.

 

I have no idea on your driving short. On your mystery battery drain check the trunk light switch, ditto the switch for the console and glove box lights. I had this problem on a Cutlass several years ago where the light inside the center console wouldn't turn off. This would consistantly kill the battery overnight. Took me FOREVER to chase that down....

 

get a meter, put it on current flow setting, disconnect ground wire from the battery and attach (+) probe to the cable and (-) to the battery. check for parasitic current. IIRC, it should be no more then 100 milliamps.. if it is.. i guess start unplugging fuses 'til ya hit the problem.

 

Nope, no underglows or lighting of any kind other than stock. No stereo whatsoever other than a head unit installed, no speakers, nothing.

I had already traced the current drain to the Alt S fuse which was taking almost 4 amps when the car was off. The only other drain was the BCC module which showed about .5 amps, but that is normal due to the alarm.

So now, we're going to swap alternators and see if everything was caused by the aftermarket unit. And if it wasn't, at least I'll have easier access to all the wiring so I can inspect/replace.

 

We had already done that a few months back, that's how I found the Alt S fuse.

Now I'm thinking I have a different problem, but I'm hoping it is related to the same issue so when I fix it, at least it will be totally fixed.

 

bump and best of luck. I had my share of electrical problems in the past and they pissed me off to the 3rd power.

 

100% it's the alternator.
this happened to my ford.

 

And you are all winners! Sure enough, it was the alternator. Basically, it's larger than the stock case, so it sits closer to the engine. And there is a nub on the alternator case that is next to the post, so when we put the new motor in last May, it looks like we accidentally got the wires between the nub and the motor, and it slowly ground away the insulation and grounded out.

Here is a new question though. I understand that on the stock alternator, there are two signal wires, a constant 12V and a keyed ignition turn on. With the Can Am, I only have one wire as the other one is run back into the voltage regulator (it came that way). Any ideas on how it's supposed to be run, because it appears that this has been the cause of my voltage drain, the voltage regulator is always open.

 

Ask Deezo, his CamAm is still running.