I have a massive power drain in my system. The car has been megasquirted. Since then the battery has been losing charge little by little. At first it was maxing out at 13.8v, then 13.6, just the other night it dropped to a little over 10v...needless to say the car was barely able to run and the injectors started shutting off. The alternator has been changed and the car has a new battery and the problem persists.

Setup:

Turbo

- Hahn S16G, Hahn manifold, FMIC, Greddy type-s BOV, stl piping, internal wastegate, Hallman Pro boost controller, custom 3" downpipe

Fuel

- Walbro 255lph pump, aeromotive 1:1 fpr, Megasquirt (v3 board), 450cc injectors

Ignition

- Crane Fireball ignition box, MSD coil pack, MSD wires, NGK BKR7E plugs

Engine

- Wiseco 8.8:1 pistons, Eagle rods, minor head-work, greddy 2.75" catback exhaust

Do you use a laptop to monitor your megasquirt?

not usually.

turn off everything
alarm, clock radio, everything that draws power with the engine off that you know of.

then unhook the negative batter cable
then hook a test light or a voltmeter between the negative battery post and the negative battery cable
if you get current then yes you have a drain
start pulling fuses until the light goes out
that is the circuit where the drain is

Alright just did this. Really did not have anything to unhook that pulled power while the car was off. With the car off and the negative cable disconnected from the neg. terminal, used a voltmeter and got around 12.18V. Went through every fuse except for the Alternator fuse and the one just above that because they have to be unscrewed and removed. The only time the current dropped was when I pulled the ignition fuse and then it was dropping only very slowly.

It started happening right after you installed MS right? Take a voltmeter and check where you connected your power sources for MS. Chances are you connected it to a fuse that is on all the time.

Well it only loses power when the car is running. When the car is off the battery doesn't seem to loser power.

Oh yea, another piece of info to throw in - yesterday I was working to adjust the wastegate because I played with it earlier when I was getting boost spike and was just trying to get it back in the right position. Too far one way causes it to overboost and too far the other way makes it very difficult to start boosting at all.

Anyway, I started the car and was letting it warm up- it was sitting steady around 12.06v to 12.20v according to the turbotimer. Suddenly it jumps to 13.70v to 13.90v and stays there. I get out on the road and give her WOT and back off b/c I'm overboosting again. Get to the end of the road and my voltage is back down to 12.20. Turn around and drive back to my house, just as I am pulling into the driveway the voltage jumps back up to 13.80v. I shut the car off and let it cool so I can adjust the wastegate actuator again, when I start it back up it is at 12.20v, now it's dropping again- last I saw it was around 11.90v which theoretically isn't even enough for the MS to work.

Do our cars have any kind of electronic load detection to tell the alternator to turn off and on?

the ecu

Thanks for the input guys, I found the problem. Turned out to be that the nut holding on the wires to the back of the alternator fell off, lol.