So i just need some help hopefully somebody has been through the same thing before i dig into this thing.

Started my car this morning it fired up no issues, so i typically let it idle for like 15-30mins before i go anywhere it just habit plus its cold out their. i was having a conversation and i noticed it sounded as if the car was misfiring and having a hard time running. So i go back outside open the door and notice the cluster is dead but the brake light and a few others are very faintly lit. i turn the car off and try restarting it but its dead making the typical clicking noise of a dead battery. i was just working under the hood of the car this weekend making some custom relay etc getting my car ready for new parts. So i disconnect the relay, loosen and clean my battery terminals then grab some some jumper cables and try restarting the car and it fires up no problem. however while it is running i notice the battery light is on. i go to disconnect the jumper cables and everything stays lit for a while then i notice the ABS and slip light come on and the cluster starts acting as if it was to cut out again. At this point i figure the G is not going anywhere until i get this figured out, it revved but it was a little weak and shaky. i drove the car yesterday and it was not giving me any issues no lights were on outside of an blinking airbag light.

My battery is an optima yellow top it is like 1 yr old, so i doubt it is the problem, checked my alt fuse its fine. When i made my relay after i was done running the wires my airbag light started blinking but i didn't think much of it i was going to get to it this coming weekend borrow my friends code reader that can read airbag codes. I also used Cylinder 1's ignition coil for my signal to the relay. Sidenote: i learned this car does not cut ignition some times for 3 mins after you actually leave the car which is interesting. But these are all the changes that have happened over the past 3 days. I'm wonder if the airbag light blinking was the first sign of something being wrong with the charging system or is it a separate issue.....or may the force be with me?

 

Typically, if the battery "idiot light" illuminates when the engine is running the alternator is not charging the car. In this case the car is running entirely off battery. When the battery gets low there is not enough juice to run the engine.

That being said, do you have a digital multimeter? What is the voltage of the battery as it sits/everything off? Also, with the engine running (when it is running), what is the voltage at the battery? With the engine running you should be reading 13-14V. In the old days we would crank the engine and with it running disconnect the negative battery cable. If the car died the alternator was shot. Don't know if that trick would work these days, though...

I just went through a similar issue with my Optima Red 2 weeks ago. Apparently, once the voltage on Optima batteries drops below 12V, the electrical system gets "wonky." My Red Top was reading 11.6V just sitting. In my case, the negative battery cable stretched and was not keeping good contact on the post. Once I replaced the cable and charged the battery all has been well (knocks on wood!)

While not identical to your issue, with Optima batteries, the voltage must be maintained above 12-12.5V or there will be electrical "gremlins." I do not know what your relay project entails, is it possible that with the car off it is draining the battery?

 

i was looking for my multi-meter since yesterday can't find it, lol. i'll try it finding it and testing the battery seeing what voltage i get and try restarting it. The relay is for my flex fuel sensor, so i needed an ignition source and the easiest one to get to for me to use as a signal was off the ignition coil. I think the terminal trick will still work if its running purely off battery i did not try it though. oh btw, car has a new serp belt, idler pulley and tensioner, less than 6 months old. check the belt its on there and tight. I did a lot of work to this thing to keep it reliable and then seems like the alternator goes out....cars.

 

It is somewhat rare for alternators to go bad but anything is possible. I would recommend you double check all of your wiring, test your voltages and go from there. If the battery voltage is low, be sure to check your negative battery cable and the connection at the current sensor. As mentioned, I just had to replace mine.

 

Big mistake! No need to warm up a vehicle. Just drive slow for a mile or so as you are just wasting gas and causing air pollution.

You may have damaged your IPDM, ECM or both along with the air bag module?
I very much doubt if your friends code reader has the ability to diagnose the air bag?

What is it you are attempting to accomplish with a relay connected to an ignition coil?

 

I dont think letting a car idle for a few minutes is a big mistake. old fashion but nothing harmful outside of just the air pollution if you are really trying to split hairs. i was actually glad i did that because my car is still at home and not stuck on the side of the road, old fashion saved me some stress lol. His code reader can actually read airbag codes, its not the cheap autozone one, it's an autel. The only thing i was looking for under the hood was an signal for the relay to send power to the flex fuel sensor. So i was not drawing current from the ignition system just using it as a trigger. the power for the sensor was coming directly off the battery. unless i have a faulty aftermarket relay.

But that leads to a good thing to look into i did not think about the ipdm. I'll test the voltages first, then the battery/alternator if those end up not being the issue I will try and source a ipdm/airbag module, i have another ECU i was planning to switch over to it for tuning purposes. I think its an issue of the voltages get so low that the other systems cannot be powered such as vdc abs radio those things turned off after i detached those jumper cables. im hoping its just the damn alternator took a ****. At this point i know its either the alternator has failed or not getting the signal to charge.

 

I wouldnt sweat the ECM/IPDM/SRS/BCM/or any other module at this point being "shot." I am 99% confident that you have a battery/alternator issue.
- check your voltages;
- use a battery charger and make sure your Yellow Top is fully charged (≥12.5V min.);
- check all of your wiring/connections at the alternator, battery, and especially any wires you added/modified for your project;
- check-off your fuses;
- verify alternator output (≈14.5V +/-).

Go from there. Don't start throwing parts at it until your certain of the issue.

 

I agree and that is what i am thinking. It's good to know what else could possibly go wrong as well so i have some sort of direction. The only modification in the harness is when i tapped the 12V wire off the ignition coil. Everything else was just running wires through the little rubber grommet next to the battery. I did check the voltages, the battery was pulling 11.5V, when the car was off when it was on it was 10.7V when i disconnected the battery it instantly died. I also noticed a strange grinding noise when the car started it was there for like 5-8 sec then went away i hope that was the alternator destroying itself and nothing else lol. Next step is taking the alternator off and getting it tested and go from there. So i will work on it with in the next couple of days, forgive me its 35* and windy here plus i don't have a garage so i will not be working hopefully in the next couple of days it warms up or i'll just hire somebody to swap out that alternator.

 

If the car died once the battery was disconnected your alternator is toast. Period. While you are planning on getting it swapped out, put your battery on a charger/tender to build it back up.

We are probably neighbors, indirectly. It is only 33° here and the wind is howling- of course I'm at the beach so... but this is NC, it won't stay cold for long.

Good luck. Keep us updated, plz.

 

OEM battery needs distilled water in the cells, pop the cap cover and refill each port with distilled water

 

Alternator replaced and everything is working again except for that airbag light so i still have some diagnosing too do with it. Hopefully its just something small i can easily fix.

I'm just taking a wild guess that you didn't read the part how i installed an optima less than a year ago lol

 

Glad you got it sorted, so far...
Yes, Optima's are sealed batteries
Did you try resetting the airbag light? Worth a shot...
SRS Reset Procedure
I had to do it once when I did my AV swap, you have to be quick, though.

 

didnt see it on mobile browser, I'd check your other grounding straps then

 

I'll give that a shot today.

i did redo my grounds, it seems to have just been the alternator fortunately. i also have added grounds to the car. Not sure if they do anything with more modern cars but you can never have too many grounds.