Well, this is the third time my car has done this in 3 months.. it's getting aggrevating (sp?) I never leave anything on in the car, my E-fan stay's on for about 15 seconds after i shut the car down, but that can't (over time) kill the battery can it? I've been thru 2 Altenators, and 3 battery's since i've owned the car. It's getting rediculous! I dont think she is going to start tomorrow morning. i can feel it.

Something (ECU, COMPUTER, SOMETHING) is staying on after the car is off, and it's killing my battery. Once it's started all lights are normal, no flickering nothing. but shut her down, and she starts, real slow, like it has a dead battery. and over night, it will barly turn over. any help would be great
thanks
-Markus

 

You have any aftermarket audio. alarms, etc?

 

check for a short somewhere..

what does the car charge at? im actually thinking the batteries are fine, but your new alternators are putting out a **** charge or something..

FCs are known for electrical problems.. a bad electrical signal / short would NOT surprise me at all..

 

if there's a short somewhere in the system, it will discharge the system over night? i never knew that. the only aftermarket electrial thing i have is an E-fan. my radio is a cheap walmart radio.. nothing special.

like i said before the E-fan stay's on for about 15 seconds after i shut the car off.. shouldnt harm it right? anyways, how would i go about checking each circuit? how would i know which one is bad, and what exactly can a do about a short somewhere?

I guess i could bandaid the problem by running a batt. kill switch correct?

it woulnt fix it, but if i kill the switch than the batt definatly isnt getting drawn.. only problem, my radio will be unset all the time, and wont that screw up the cpu/ecu somehow?

thanks for the insight guys.

-Markus

 

dont make a kill switch, just remove the ground terminal off the battery..


Icemark (in another thread) posted an excellent way to find a short.. i cant remember what he said.. try a search for that post - its a good one..

 

It might affect the ECU memory, which can affect performance and fuel economy, but otherwise that would be it for the problems with the kill switch.

 

im not so sure about that..

i disconnect mine all too often to do work (anything electrical = disconnect battery) and i never have any problems..

 

i had the sam eproblem...has to be a short....i changed th elaternator also but check for a short cuz i had my right front fender smacked and my headlight wouldnt go up up down and the light motor shorted out the switch and whenever i had the rtractor fuse in it kept illing battery until i figured it out....so u have short...period...i went thru two batteries in week...5 in a year

 

Look for the short. Either use a multimeter or pull one fuse or relay each night. Eventually the car will start normally and since you know which fuse/relay was pulled, work from there.

Use a quality battery. Cheapo dept/auto store specials don't last long.

Improve charging by directly connecting alternator to battery. Check all grounds. Run some jumpers.

Bump your idle. IMO, the 750rpm idle is too low for a 12+ year old car. I set my idle at 900rpm and everything is better. I also didn't notice a reduction in MPG which noone with a rotary worries about anyway.

Check/replace battery/starter cables.

Efan for 15 seconds shouldn't cause an issue.

 

also another thing which i was doing until i figured it out was to unplug the bettery everytime i had it parked over night as to nit kill it....but then uhave to be careful when u drive it might come loose which happenned to me a few times and car died right there

 

Or pull each fuse and put a DMM into the circuit so you can measure the current through each fuse. With everything switched off you'll be able to see which circuit is drawing current when it shouldn't be. The current is probably quite small, so a DMM that can measure 10A should work OK. Start with the engine bays fuses and narrow it down from there. Not a bad idea, I might do that myself. Everything goes a little dim at 750rpm...

 

Well, i took the Altenator off to have it tested... again!. and it tests fine.. than we put it back on the car and did a load test. no charge. So get this, than i say Fu*k it and purchase a new altenator. The machine at discount is faulty.. it was telling me i have a good Alt, when i didnt. After 140$ reman altenator she's running perfect. strange thing is, i didnt change anything other than install the new alt, and the idle bumped it self up to about 900-1000. Is it normal? i know the regular idle is 750. but should i even bother lowering it back down?

So it was my alt after all. but damn. the last one was only about a year old with under 20k on it. oh well. all is good nice 13.8 with everything on (lights, wipers, radio, fan) with all off alittle over 14...

-Markus

 

Take the negative cable off your battery, connect a test light to the chassis and the other end to the negative terminal on the battery. With the car off, if the light is on, you have a voltage drop. As mentioned, start pulling fuses until it goes away.

 

good luck mine has a gremlin tooo i think i'll have to re wire the whole car be fore it goes away.. but it only happens if i leave the car for more than a week other wise i never hav the pob....

 

a simple current draw test on the car (with the engine not running) would tell you if there is a draw problem (and it won't be the ECU, the ECU uses less than 5 mA draw to hold memory, and that is not enough to drain the battery in a month.