Drain? Short? Bad alternator? - SR20 powered s14

[ep3scott]

Hey folks,



I'm a long time lurker around these parts and I figured you guys would be the best people to help me fix my newly acquired s14. It's running an s14 SR20 that was fitted by the previous owner. It runs like a champ and boosts great, but since I have had it it's been having a couple of electrical issues that I'm struggling to diagnose. Bare in mind the battery is relocated to the trunk.



Firstly I noticed that when I turn the key in the ignition 2 notches the brake and battery lights come on. They turn off when the car fires up.



A few days later I noticed that the car would struggle to fire up, it would as soon as I gave it a squirt of gas but still not on a dime like before.



I took the car to autozone and they checked the battery which they determined to be bad, which I replaced with a new battery.



3 days later I jump in the car and nothing..no power at all. So I call out AAA to give me a jump and the car starts fine. I get home and it dies again when I try and start it. Luckily I've got a trickle charger to charge it up.



Weirder still I charge the battery and it shows 100%?!



I take the car to autozone again and they test the alternator and battery which both seem to be in working order with the battery 100% charged.



Since then the car has been fine, wierdly. It seems to start up fine every time as when I first got it.



Tonight I checked the battery (whilst the car is off) which is holding 12.8 volts across the terminals and 12.8 across the disconnected negative terminal and the negative cable which if I'm right is indicating that the car is drawing power even when the car is off. I checked the ohms between the negative terminal and the chassis which is reading spikes of upto 30ohms whilst the stable consistent reading is around 1.1ohm.



Basically my question here is..wtf is going on? Does this sound like a bad ground? A draw? A faulty component?



Any help would be great dudes! I need to fix this before I can start pushing for 300hp!

Some photos of the old girl:
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[frankies1390]

do you have subs and amp? dome light connected? faulty door switch? its hard to determine. is your alternator fuse (75amp) good? its always a nightmare chasing down electrical draws! have you tried disconnecting the battery over night and seeing what your numbers are?

[No 240.. No id]

Disconnect every after market parts installed and see how it is, including an alarm system if you have one. Usually these parts are not installed right and cpuld cause that problems.

[No 240.. No id]

Also, start the car, leave it running and disconnect the battery and see if it continues running.

[ep3scott]

Hey frankies, thanks for the reply!

I don't have a sub or an amp, but I do have a few gauges in the car. It seems like the last owner disconnected a bunch of stuff and left wires going here there and everywhere making diagnosis that bit harder.

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Today I went through the car with my multi meter removing fuses one by one to see which is causing the battery to drain, I must have checked 40 fuses inside and in the engine bay and none of them stopped the negative terminal to negative cable voltage showing 12.8 volts, making me think that maybe something is actually wired up without a fuse or a component may not be correctly earthed, are there any good tests for this?

I checked the grounding of the negative cable and I debrided the earthing point which was right next to the battery to ensure that the connection was strong. It seems to be pretty well hooked up.

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I was checking under the dashboard and I'm
Not sure if the previous owner has relocated the fuse box or if it's just badly designed but in the drivers side footwell you can see things are alittle messy.

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At this point I'm at a loss, the engine fires up great but in worried it's going to shit out on me again.


Sent from my iPhone using Tapatalk

[dbeiler]

Ok, you've got the right idea but some of your electrical troubleshooting is incorrect. To check a battery draw, you will not be checking for voltage. I'm not quite able to see your multimeter setting, I'm assuming you had it set to voltage. You SHOULD be getting voltage if you have a multimeter hooked up, completing the ground circuit :)

Parasitic draws are checked with the AMPS setting. Wikihow has a neat little article on the subject. Pay attention to which port your test lead is plugged into on the multimeter. Checking AMPS with the test lead plugged into the incorrect port of the multimeter can damage your meter. Refer to the users manuel or interweb for the correct port.

To check the ground cable: Multimeter set to ohms/resistance. Stick one test lead on the negative battery terminal ground cable. The other end on the chassis somewhere. The whole point of this is to measure the resistance where the ground cable bolts to the chassis. You should see a solid 1 ohm or so. If it spikes, you may not be making good contact with your test leads. Scrape and dig the lead tips into the testing surface to ensure solid contact. Still spiking? Fix your ground cable.

Disconnecting the battery while the engine is running can help diagnose some problems. Keep in mind, I have seen idling engines stall out even with a perfectly functioning charging system. For proper test execution, I suggest holding the engine at 2000 RPM.

[dbeiler]

Also, I haven't driven my S14s in forever, but aren't the brake and battery lights always supposed to light up when you turn the key? I'd imagine those bulbs should be illuminating along with the rest like the SRS and check engine light.

[ep3scott]

Thank you! This is great. I'm pretty new to car electrics and I guess ive got my.. Wires crossed?!?!..I'll redo my tests tomorrow and report back with the results!

[EnergeticPhenom]

I'm on the same boat with you with dealing with electronics issues left behind from the previous owner/s on a sr20det s14 swap. My battery was swap behind the passenger seat, for whatever reason, I don't know. I think both power and grounding cables are being ran below the chasis and into the cabin. My battery seems to get drained, and even with a jump from my other car, it doesn't want to kick on most of the time unless I get it completely charged at autozone(99%). (I don't hear the fuel pump prime in the fuel cell in the trunk). So could be some issues there.