S13 Electrical Issues

Lewbags

Lewbags

Member
Hi all,

So, to set the scene, I have an RPS13 180sx. The car is a 96 model and has an SR20DET Blacktop engine. The car is running an aftermarket FMIC, new uprated coil packs, an aftermarket air filter, a t28 turbo, braided turbo lines, a smaller battery (to accomodate larger intercooler piping), a boost controller, after market alarm system and is totally stripped throughout the back of the car.

It recently had the knock sensor go on the engine which I replaced myself. It did require a lot of messing around including the removal of half the engine to get to it.

Where the car had been sitting the smaller battery was dying and I was jumping the car to use it. Eventually the battery started spewing acid so I removed it.

This weekend I undertook the task of relocating a battery to the boot with a friend who is an electrician. I followed various guides online and everything we did was textbook. Bigger battery, bigger cabling, fuse next to the new battery and power junction at the front to fit the new power cable and any of the old wires, excluding the earth which has moved to the rear.

The car started immediately after we fitted it all up (chuffed). After turning it off and back on again the car didn't start. And started hissing and smoking from the passenger side of the engine bay... away from all the battery and wiring.

After more inspection we realised that one of the braided oil lines from the turbo to the engine was arching with the firewall.

We did some further tests and noticed that the started motor wasnt working properly and that an earth/ground cable from the alternator was loose and sparking.

I fixed up the earth yesterday but was still smoking upon starting the car from the braided oil line on the turbo.

Another odd thing happened as well. After I engaged ignition, you could remove the key and all the lights would stay on to the point where you could still indicate.

The wiring under the dash is a mess from people that have bodge fitted stuff in the past so I went in and tied everything up a bit neeter cleaner some wires and made it look more acceptable.

Any ideas? I am being told by friends to call someone as fucking around with this stuff can just cause more problems. Im based in essex so if anyone has a recommendation of someone to look at it, please let me know.
 
turbo line shouldn't arc to the firewall at all , i suspect somehow the engine earth is 12v positive
 
First up, disconnect the ECU before you fry it.

Agree it is getting 12V to the physical engine somehow. Grab a multimeter and throw the negative on the chassis and the positive on a patch of bare metal on the engine (engine hoist hook / mount is the best).

Disconnect feeds from the power junction until you find which is doing it. If none of them are check the power feed to the back for splits

Actually, has the power junction been properly insulated from the body? Chances are you're sending 12V through the body and onto the engine via an earth strap
 
Thanks for your help guys. I spent a day away from the car today thinking about the problem and have managed to fix the car myself.

For anyone that sees this in the future, i had cut the ground wire which ran from the negative on the original battery to the ground on the bottom of the battery tray and hadn't taped it up. The ground wire from the intake manifold is also connected to the same crimp as the negative on the battery. Infact they are the same wire so because we hadnt crimped it off or covered the end of the wire it was arking with the chassis which had caused the whole engine to become live. In turn making the braided lines ark with the fire wall and all the lights staying on when we removed the key from the ignition.

So there we go. A small bit of tape, 10 minutes and the car is working.
 
Errrm, you might want to check the conditions of the lines where/if they were arcing. A friend of mine had that issue, which put a small hjole in the hose, which fired oil over his manifold, which set fire to the car. Except all that was in the space of about 30 seconds.

So many issues you have mentioned so i would definitely give the whole thing a good going over to be safe, rather than assume that now it starts it will be fine ;)
 
MaccyD said:
Errrm, you might want to check the conditions of the lines where/if they were arcing. A friend of mine had that issue, which put a small hjole in the hose, which fired oil over his manifold, which set fire to the car. Except all that was in the space of about 30 seconds.

So many issues you have mentioned so i would definitely give the whole thing a good going over to be safe, rather than assume that now it starts it will be fine ;)
Click to expand...

Yeah, should've included that. I checked the braided line and luckily its okay. Didnt want any fires :cool:
 
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