I still have a short in my 1987 Iroc z 305 TPI which I have been trying to find since i bought the car so far I have replaced the Starter, Altenator, Battery, turn signal swithces, trunk pull down motor, and have tried several times to use the fuse trick. Still haven't found anything I have also checked all of the relays that i can find and I have checked the ignition module. I need some help where do i look next?

 

Have you checked your grounds and terminals?

 

What is the short causing your vehicle to do? What type of things are happing?

 

I have checked my grounds and terminals and they are good the short is causing my battery to go dead when it sits for about a month and i don't like it. lol

 

I don't think you have a short. You have something in your electronics that is drawing power from the battery. hook up a meter with 10amp scale connected inline with the positive battery cable. Then start pulling and replacing fuses until the amp reading drops. An acceptable reading will probably be about 0.5 amps (that's what they said at school, so I could be wrong). Whatever fuse you pull is the circuit that is draining your battery. Once that is found, start diconnecting components and you will eventually find which one is the bad part. Good luck with it.

 

well if something is drawing power when its not on couldn't that be considered a short. because something is drawing power on my car when it shouldnt so i assumed something was shorted and grounding and drawing power. if everything still works right but its drawing power does that mean its a component problem?

 

It's called a parasitic drain. It's when something is still working when it should not be. All components can work normal, but one of them is somehow being left on without you wanting it to be. It can be a component and most likely is. This is how you would find the right one without replacing many components that have nothing to do with what is going on. Believe me, this will save you money if you do it this way. Also make sure you check the wiring as well around the component you may find bad.

 

is it possible that the parasitic drain could be caused by the pcm since its sitting for a month?

 

Clocks, stereo memory, ECM all could be contributers to the draw.
I personally wouldn't be too concerned if it takes a month of no start to kill the battery. I would be more concerned if it want dead after a couple days. I have an 06 Monte SS that goes dead after 2 weeks sitting, because of all the computers that draw power with the key off, perfectly normal it is NOT an issue on my car. I would almost bet that you will be chasing a ghost trying to fix your concern and maybe spending a lot of time and money on something you might never find.

I would suggest if you know the car will sit and not be started for a long period of time either use a battery tender of disconnect it or just start it and let it run for a while occasionally.

 

Our cars shouldn't drain the battery even after a month. I was away for 5 weeks this winter, came back and the car started right away.

If you suspect the ECM, unplug it. As with any other suspected component. As already mentioned here, try the radio, clocks, alarm, ipods, extra gauges, simply all the add-ons. Make sure the underhood light turns off etc.

Every device on the car HAS TO be powered though a fuse (or the major circuits use fusible links, but those are not of concern). Make sure you pull ALL fuses in your car, including any underhood and add-on fuses.

Chasing down a parasitic drain isn't always fun but if done in an organized manner, it is doable.

Hope this helps.
Lou