Popping Noise at Start Up, Now No Power at All, Won't Start.

[ThomasK]

My 1987 325is cranked up just fine yesterday morning. Then later in the afternoon I went to start it and it cranked then there was a single pop noise and it just died. All power is gone except for the little clock in the center console. No priming, no cranking, no dash lights, nada.

- The battery tested fine with my multimeter
- I've replaced most of the fuses in the car trying to rule that out
- I just ordered a white Main relay since that seems like the likely culprit.


The only thing that had changed between when it started in the morning and when it quit in the afternoon was I had pulled the driver seat and installed the floor AC ducting. The only things that were unplugged were the power window switches and the cigarette lighter. neither of those should effect the car starting, and certainly not the floor ducting. I just thought I should mention it in case there are wires on the floor board I might have bumped in to.


Is there anything I am over looking?

[jeffnhiscars]

I dont think the main relay will cut all power....but the fusible link will. You could have shorted something and blown it

[zaq123]

Bentley:

NOTE -
On 6-cylinder models with trunk-mounted batteries,
check for a faulty fusible link. If no voltage is
present at the red 1 .5 mm or the 4.0 mm wires on
the junction block, inspect the fusible link. The
50-amp l i n k is approximately 6 i nches from the
battery in the 6 mm black wire. Disconnect negative
battery terminal. Carefully slice the hamess
covering open to check the link. A faulty link m ust
be replaced with BMW Part No. 1 2 41 1 706 1 1 1 .

[Kershaw]

You can swap the o2 relay around as a quick test for the main and fuel relays.