anonomousdrift

I'm kinda new here and have used the search function to help me through my problem but now im stuck and am hoping for some insight.

Arrite so I picked up a 93 coupe about a month and a half ago. car ran well (other than the brake light on the dash being lit at all times) up to about two weeks ago when the battery died on me. so I called the previous owner and he said the battery had been replaced in september of this year so I thought I had maybe left something on in the car so I jump started the car and the battery stayed charged for only a few hours before it died again. I noticed the battery light was dimly lit so after seaching on here I thought it was the alternator so I jumped it again and took it to kragen to get tested and both the alternator and battery came up good. so I started checking the fuses and three were popped in the fuse box under the hood, the 10A eng cont and the 10A horn fuses, and the FL25A mtr ret fuseable link. I replaced all three and the lights on my dash go off. I thought everything was fine but I guess it wasnt because the battery still drained if the car sat for more than a few hours. I went out and got a DMM and decided to check the voltage of the battery. I jumped the car again and the battery, when the car was running, was around 14V and when I turned the car off after running for about 15 minutes was around 12.6V so everything seemed fine with the charging system. So I started testing for parasitic drain and there was a .5A current being drawn with everything off in the car. start pulling fuses to check for which circuit was draining the battery and it turns out the FL25A eng cont fuseable link dropped the current down to .03A, which I looked up and seems to be okay. I checked the link but it wasnt popped. I replaced it anyway but the link is still drawing the .5A current. I searched and found out the FL25A eng cont fuseable link goes to the ecu so I guess thats whats drawing the current? Does that mean there is a short in the harness somewhere or that something is wrong with something else that the ecu controls? I've been searching for the solution and have finally narrowed it down but I just dont know what else to check in relation to the ecu.

Cliffnotes:
-car died, battery dead (battery about 2 months old)
-jumpstart and dies after sitting for few hours
-take to kragen
-alternator and battery good
-replace popped fuses
-battery still dies
-check for parasitic drain
-FL25A eng cont fuseable link drawing current but not popped
-replace link but still draws current
-ecu or something connected to it still drawing current?

If anyone can help I'd really appreciate it. If there is any information I forgot to include just let me know.

anonomousdrift

so no one has any ideas? im tired of pulling the fuse every time the car sits so the battery doesnt die.

anonomousdrift

so i finally got some time to work on the car. i disconnected the ecu and the battery drain stopped. im guessing this means that there is a short somewhere in the ecu itself? im trying to find a replacement ecu or just someone who can let me check if mine is bad. if youre in the irvine area and can help just pm me or post in here i guess.

Pacman

Look at the circuit which uses the fuse/fuselink. Start unplugging the items that are on the circuit and look for the drop. If the computer is the only thing on the circuit (unlikely) then replace computer, but make sure its not something else before you just start replacing things. Also look for resistance in the wiring, could be causing the computer to use more power for is memory.

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anonomousdrift

First I just wanna say thanks for responding Pacman. I appreciate any insight.

I took your advice and printed out the wiring diagram and traced out what is connected to the fusible link. it looks like its the ECCS relay, the injectors, MAF sensor, and crankshaft position sensor. I pulled the relay and checked which part of the relay was drawing current. it was the part connected to the MAF sensor and crankshaft position sensor. I disconnected the MAF sensor and it dropped the current down some but not enough to eliminate the drain. So Im going to check the crankshaft position sensor tomorrow and see what happens.

anonomousdrift

I disconnected the crankshaft position sensor and the current being drawn wasnt effected. i disconnected each injector as well and that didnt make a difference either. so all ive figured out is the maf is drawing some current. i checked the ecu circuit diagram again and found out that the distributor, ignition coil, knock sensor, throttle position sensor, o2 sensor, and power steering oil pressure switch are on the circuit as well so im gonna check those as well once i get a chance.

anonomousdrift

okay well I disconnected the 02 sensor, distributor, ignition coil and throttle position sensor with no change to the current drain. I wasnt able to reach the power steering oil pressure switch or knock sensor so i dont know if those are having any effect yet.

another thing that happened the other day was that while I was driving the electrical fan that is installed came loose and partially disconnected and ended up being drug under the car for about a block. I pulled over and saw thats what it was so I turned off the car so I could reposition it and drive home. when I started the car up again the check engine light was on. I parked and checked under the hood for anything damaged other than the fan and everything seemed intact. I left the car to sit overnight and when I went to check on it the next day the check engine light doesnt come on at start up and the car wont start. so now Im really leaning towards it being a faulty ecu thats causing the battery drain.

so again, if anyone is in the socal area and can help me out with an ecu, ecu check or just help me diagnose the problem in person, id appreciate it.

anonomousdrift

well i guess the check engine light thing was just because i didnt put the relay back in tight enough so the connection wasnt being made so that was a false alarm.

today i had some time to kill and decided to pull out the busted electric fan. while i was disconnecting all the wires that had been ran to the switch (not my wiring, previous owners), i noticed some cut wires next to the fuse box. heres a picture of the wires and connector:



i havent gotten around to checking what it connects to but im guessing its to the original fan system? im not sure.

also, i went ahead and picked up a replacement ecu and, like you said pacman, didnt change the problem with the battery drain. however, i did find another wire that was cut. it was next to the ecu going into the door. heres a pic of that:



im not sure what this goes to since i dont recognize this kind of wire at all and it just goes into the door. im going to check the FSM for what both wires are connected to after work but if anyone knows what they are let me know.

PhopsonNY

Very systematic,

Did you ever figure this out?

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Above!!!

anonomousdrift

yeah i actually did. i think it ended up being the 75 amp fusible link that went to the alternator. visually it didnt look like anything was wrong with it but i guess it was blown. went to the junk yard and pulled some and fixed the problem.

extra20

The grey connector your holding with the glove appears to to the iat sensor connector

PhopsonNY

Glad you figured out why your car wasn't starting...

I wanted to know if you figured out what was causing the battery drain.

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Above!!!

Jtultra

This right?

fliprayzin240sx

Couldnt you just read what he said was the solution a couple post up or PMing him instead of bumping a 1 yr old thread?

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jrifta_status

sell the beeyatch

jrifta_status

do it... do it now!!!