Mega Battery Drainage

[av3n1r]

Ok, I've had this problem for a little while now and finally decided I want to figure it out. Something is draining my battery and i have no idea what it is. I've searched on here, google, etc. and i've found alot of helpful info but nothing specific to my situation.

With the battery in the car (S13 w/ S13 SR) and connected with the car and everything in it off (suposedly) and doors shut there is a massive drain on the battery. I can stand there and watch the voltage drop on the multimeter (.01v about every 15 sec).

I hooked the multimeter up many different ways in many configurations using resistance, amperage, and voltage settings while pulling fuses to see what I could find. I started by using the method found in post # 11 here (http://zilvia.net/f/tech-talk/261296-battery-drain-voltage-drop-car-dies-while-running.html) but I couldnt find anything (maybe I was doing something wrong). Secondly I connected the leads on the meter to the battery while it was installed in the car (in volt mode so i could watch it drop) and started pulling fuses one by one until it stopped dropping. Every single fuse on the car I pulled did nothing until I got under the hood. I pulled the 25a "ENG CONT" fuse and the reading on the meter immediately started going up (7.62v, 7.63, 7.64, 7.65, etc.). Next I used the method found in post #7 here (http://zilvia.net/f/engine-tech/330806-power-drain.html) to determine that with the car sitting in a normal state of "parked for the night" there is a .4a (400ma) drain on the battery. With the 25a ENG CONT fuse pulled the drain goes from .4a down to .08a (80ma).

I guess my real problem is what the hell does the 25a ENG CONT fuse do?? I assumed 'Engine Control' but all I could find was very vague threads/info about how it "controls the engine" and how everyone apparently pops these fuses quite frequently, but being that popping this particular fuse is not my issue I'm looking for more info on what it does, what else is on that same circuit, or anything. I have no idea what the fuse is for and no idea where to start looking or what to start looking at in order to isolate the drain.

Any help/input/ideas/thoughts/concerns are greatly appreciated, and I will try to answer any questions as quick as possible to help anyone help me figure this out. TIA Zilvia.

[RebornS14.HTC]

what kind of battery is it? test the battery by taking the positive lead off the battery. however long it takes to drain your battery on a normal basis, leave it off for that long. put it back on and see if the battery is still able to start your car.

if that works then its probably something aftermarket. disconnect all the constant wires that's not factory. boost gauges, radio, amps, all that stuff. don't worry about the alarm if you have cause they barely take any power as long as the sirens not going off.

that's just my 2cents. i dont care if you have a new battery. the battery is always a suspect. i've had 2 odyssey die on me like that. too small for a car with amplified stereos, gauges and all. i have a braille now but even that struggles when i have the music on. planning on relocating a full size optima to the trunk soon. before the end of the month =)

[av3n1r]

what kind of battery is it? test the battery by taking the positive lead off the battery. however long it takes to drain your battery on a normal basis, leave it off for that long. put it back on and see if the battery is still able to start your car.

if that works then its probably something aftermarket. disconnect all the constant wires that's not factory. boost gauges, radio, amps, all that stuff. don't worry about the alarm if you have cause they barely take any power as long as the sirens not going off.

that's just my 2cents. i dont care if you have a new battery. the battery is always a suspect. i've had 2 odyssey die on me like that. too small for a car with amplified stereos, gauges and all. i have a braille now but even that struggles when i have the music on. planning on relocating a full size optima to the trunk soon. before the end of the month =)

I have a full size optima redtop (04/2009) in the trunk, 150a inline fuse about a foot away and a dist. block under the hood. I havent tried what you mentioned yet but if the battery is out of the car and I put the meter on it, the voltage goes up so I assumed the battery was ok. And if I let the battery sit completely disconnected it holds a charge just fine and I can hook it back up and start the car no problem.


One other thing I didnt mention was that while the 25a ENG CONT fuse was pulled I turned the key to see what would happen, of course it didnt start and the only thing that came on inside the car was my turbo timer (which didnt work right anyway) so thinking that was the drain problem I ripped the timer out and disconnected the timer's harness from the ignition harness. At this point I reconnected the ignition harness and put the fuse back in.... still draining. Then while the ignition harness was disconnected and the 25a fuse was in place there was no drain on the battery. As soon as I reconnected the ignition harness the drain returned.

[RebornS14.HTC]

ok but the fuse is a fuse. it's not gonna drain your battery. your looking for something attatched to that fuse and that can be anywhere. gotta start with your aftermarket electronics. one by one.

[av3n1r]

I realize that the fuse itself is not going to cause the drain, that's why I asked what it was for and what else was on that circuit. I was just pointing out that because that's the fuse that changed something, that's the circuit with the problem. I actually am outside messing with the car right now. The only aftermarket electronics are 2 gauges, a pioneer avic n3 headunit and a boost controller. I have ruled out the gauges and boost controller. I'm getting ready to disconnect the radio and try again.

[av3n1r]

I think maybe I figured it out. It wasnt the radio either however it did hit me that the constant 12v wires for the boost controller & gauges were connected to one of the wires on the ignition harness (red/white, dont know what its purpose is). From unplugging the ignition harness previously and finding out that the drain stopped while the harness was unplugged It hit me that maybe I should take those coinstant 12v wires off the ignition harness and move them elsewhere. So I put them on the same fused constant 12v wire that the radio is on, checked to make sure everything worked properly, and for the past 10-15 minutes the battery has been holding at 12.05v.

[av3n1r]

Pretty sure the problem is solved. Checked the battery when I parked the car earlier today and it was at 12.01v. Just checked it a few minutes ago, after the car sat for roughly 8-9 hours and it was at 11.93v. Just need to give the battery a good full charge now.

It was indeed my boost controller and gauges, much thanks for your insight Reborn.

[PhopsonNY]

So were you right?