Dead short? chime in lol

[F34R]

So the issue started a few weeks ago with my Parents e30('87 325e)

Here is what happens: Car will just die at random for no reason. All power will kill out and the battery will be dead. But here is the thing, I changed the alternator and installed a brand new battery. Checked running volts off alternator and came back with a bit over 13v. So that is good, all relays are spot on but the damn thing will just die while driving it.

Here is where is gets fucked up, so my brother came home with it and said it died on him. But then started later that night after work So I go out this morning and sure enough there is only .05v in the battery...... then I remove the power cable and test the battery and it comes back with 12.04-09 more than enough to start it. But when I hook it back up and turn the key to the on spot and all lights work 100%. Headlights are bright with the dash etc. Then you go to crank it and you just get the click and everything goes out.

I am at my wits end on electrical trouble shooting list. I have went though the WHOLE motor and every ground is hooked up and tight, there is no green cables or split rubbing wires etc. I swapped the motor a year ago and have had no issues till now.

Good things that I have replaced:
ICV
TPS
AMF
Relays
Starter
FPump
Alternator
Checked ALL fuses

It is getting fuel and spark, it I hook up a jumper to it there is no issues...

Honestly I never post about trouble shooting because I have always sorted it out. But being this is my folks car and need it for work I need a fix fast. I am currently lending them one of my BMWs to drive till I can sort this out. uggg


ECU has not been tested yet, I do have three spares. So that is my next thing to test/change.

[ryans09sstc]

So I go out this morning and sure enough there is only .05v in the battery...... then I remove the power cable and test the battery and it comes back with 12.04-09 more than enough to start it. But when I hook it back up and turn the key to the on spot and all lights work 100%. Headlights are bright with the dash etc. Then you go to crank it and you just get the click and everything goes out.

So when you voltage test the battery with the cables attached, it reads 0.05 V?
And when you disconnect the cables it reads 12.04V ? Or am I not reading it right?

[F34R]

So when you voltage test the battery with the cables attached, it reads 0.05 V?
And when you disconnect the cables it reads 12.04V ? Or am I not reading it right?

You're reading that correct fluke maybe? It was fucking cold out when I did the test.

Here is an update:

So I swapped the battery from the truck to the e30 and it started up no issues. Then I disconnected the power side of the battery. Car died right on que, FYI not supposed to happen. I tested the alternator before I pulled the battery cable and it was functioning perfect. So that leads me to believe that there is some wire in the harness someplace that is broken or loose that is not allowing the alternator to charge the battery/run the car. FYI The alternator will run the car without a battery hooked up.

So I am now tracing the power wires to make sure everything is connected.

One thing at a time, oh how I LOVE cars...just fixed my e24, the terminal connector & power lead to the starter were bad. Good old green infected cables sigh*

[scrowner]

On the passenger side of the car in the engine bay on the fire wall there is a distribution point for the battery. I would inspect this. Your problem sounds a bit similar to a fellow E30 racer where this distribution point was cracked and doing some bad things.

[F34R]

On the passenger side of the car in the engine bay on the fire wall there is a distribution point for the battery. I would inspect this. Your problem sounds a bit similar to a fellow E30 racer where this distribution point was cracked and doing some bad things.

Thanks, that was at the end of my list...should have been at the top xD

[F34R]

Took a video, let me know if I missed anything...

[E30_fiend]

Here is something to check. On the back of your key switch, there is the harness that plugs into the key switch and it clips to the steering column. Its supposed to clip in place. My guess is one of those clips is either NOT clipped or broken off. If that harness loses connection, it would be like shutting the motor off. It also explains why when you go to start it sometimes, everything will shut off. When you turn the key switch, its supposed to turn the assembly inside the harness to make contact with the hot wire and start the car. If the clips are broken or not clipped in, just the motion of turning the key could pivot the harness off of the key switch, killing al power to the accessories and the motor.

I hope that makes sense.


Taylor

[E30_fiend]

this is the harness Im talking about

[E30_fiend]

sorry about the big picture

[E30_fiend]

another thing to check is your main fuse on the positive cable about 12" from you battery.

[F34R]

I will check all of that thanks for replying. But right now my parents took it out for a few hours and I tested the battery when they got in. Still holding charge, that would mean it is fixed or so it seems. I will know better in a few days. Time will tell

[E30_fiend]

Good luck dood

[scrowner]

What was the fix? If you video explained the fix - sorry did not listen, only viewed.