deputy865

iTrader: (5)

So my car has been down for awhile due to what I believe was my ECU going bad (check my build thread). Got the ECU all recapped and ready to go, did a bunch of maintenance to the car while it was down etc etc.. Put the new ECU in, had to jump my car.. Kind of figured the battery would of been dead anyway for sitting so long. Got the car going, it drove perfectly fine. No issues anymore. Smiles all around.

While driving, I tried to give my train horns a little honk. They didn't work, so I figured no big deal, I must of kicked the ground loose as the ground for my remote switch is right near my feet under the carpet. So about an hour +/- after driving the car and parking it, I decide to go fix my train horns.. Only to find that my battery was dead. So I was thinking that either the battery was shot and didn't take a charge the entire time I was out driving, or I have a massive battery drain.

Went and exchanged my battery for a new one (thank god for warranties). Threw the battery in and we're good to go. I head back outside today to put my interior back together and clean the car up. Dead battery.......

So how in the hell do I track down a leak in my system? The last electrical changes I made to my car was doing the 12v mod to my fuel pump ECU and I left the plug for my fuel pump ECU unplugged.... Pretty sure I didn't do anything wrong here..?

Lost.

Shane

1JZPWRD

iTrader: (59)

Shane, I still think the battery drain is the main ECU. There have been many members who have complained about this symptom only to find out it was the ecu the whole time. I would recheck the ecu again or try another to rule that out. I dont think the fuel ecu mod is doing this. I say this because all of the other members who has done this with good luck, myself included. To rule that out. Disconnect the lines now and put back factory. Then trickle charge your battery overnight. Then report back symptoms to us. Whike you are at it, check the grounds to the frame from battery. Look for rusted bolts or bad connection in the cables itself. For a piece of mind, change them anyway. I hooe this clears up some issues with your car. Again I dont think it is the ecu mod due to when it is triggered on, etc.

deputy865

iTrader: (5)

I will do that, sir. Thanks for the input.

Only reason I wanted to half blame the ECU mod is because I didn't plug the plug back in to the fuel pump ECU itself, even though in the instructions it shows that it was plugged back in.

I thought I might of ruled the ECU out. I had it recapped and all the components that were bad on it replaced.

Shane

HiPSI

iTrader: (2)

Hey Shane,

Do you have a voltimeter? Are you sure your alternator is charging fine? If the alternator has died this would obviously explain the issues you are having.

The fuel pump mod could be causing the draw, but I doubt it. The fuel pump ecu only gets voltage when the keys are in the ignition, and then shuts off when you power the car off. Unless your fuel pump is running non stop without the car on, I doubt this is your issue.

Also to check for a parasistic battery drain there are multiple how to's on it. You will need a voltimeter to check and then just start pulling plugs on electrical components (& fuses) till the drain stops, that's how you pinpoint what is causing it. You will want to make sure all the doors are shut, and the car has been sitting for alittle while.

deputy865

iTrader: (5)

In my mind, I ruled the alternator out because the battery died in the car while it wasn't even running. I threw the brand new battery in, didn't start the car, let it sit for 20-24 hours, went to check on it annnnnd dead. Would a bad alternator still do that to me?

HiPSI

iTrader: (2)

The only way to truly know is to check with a voltmeter what kind of draw you are seeing, then the fun starts with process of elimination finding what's causing it.

Sounds like if you set a new battery in and it died without running the car then you must have something killing it. If you can take the car to advance auto they can put a diagnosis tool on the battery to check the charging system.

deputy865

iTrader: (5)

Ok. Got a multimeter hooked up to it.

The battery was dead, obviously, so I jumped the car and let it run for a good 20 minutes or so at idle, revving it up a few times. So the battery probably wasn't fulled charged, but it was good enough for the test.

I set the multimeter at the following settings:

Red wire hooked to the 10A port
Black wire hooked to COM port
Dial set to "200m"

I then unhooked the negative terminal and touched the positive lead to the ground cable itself and the negative lead to the battery post. The results would show that I was (assuming I had everything hooked up right) 02.5 but then it would drop and settle down around an average of 00.7. Sometimes it would spike up to 00.8, but for the most part, stayed right around 00.7. The drop from 02.5 to 00.7 was basically instant.

From my understanding, I shouldn't be seeing anything? Thoughts?

deputy865

iTrader: (5)

Checked it this morning. Meter dropped to 0.03 which is equal to 30 miliamps, but that is within range of normal. Unplugged the big clip on the back of my alternator and got no changes on the meter.

So lost.

HiPSI

iTrader: (2)

What's your voltage at idle? Is the alternator charging properly?

deputy865

iTrader: (5)

Funny you mention that, because I was JUST about to post/edit and list my findings on voltage at idle.

Unless I was high on paint fumes from painting my little boat motor , I swear I saw voltage in the neighborhood of 18v~.. Which is obviously no bueno.

So that would mean bad voltage reg..

Which means alternator issues.

If I rip my alternator out and have it rebuilt, would they (the rebuilders) be able to repair a bad voltage reg?

Shane