Here's the latest everyone...
I hooked up an auxillary power source - 12v dc - directly to the suspect fuel pump. Actually I didn't 'hook it up'... I just touched powered electrodes to the proper electrical contacts on the fuel pump.
What happened was that the suspect fuel pump 'hummed' but did NOT make the pumping sound I expected. The hum was akin to any electrical 'motor' that wanted to 'turn' but was frozen up.
Next, I tried the same experiment on one of my properly operating E30s. This time the known-good fuel pump made proper fuel pump noises - significantly different then the suspect fuel pump.
From this experiment I have to believe that the suspect fuel pump 'motor' is 'frozen'. Indeed, early in my investigations, I had found fuse #10 blown. That's one of the fuel system related fuses, I believe. That data point lines up for me - frozen motor tries hard to turn and blows a fuse when it cannot. That seem right to you guys?
I'm gonna repeat my test lamp experiment to see if power is getting to the fuel pump. I did this yesterday with a no-power result but I've improved my primitive test lamp apparatus since then and I'm gonna repeat the experiment.
I'd like to think that I've got only a single problem - that of a frozen fuel pump - but an electrical gremlin cannot yet be ruled out.
Woo Hoo! Some progress. I'm not terribly intimidated about replacing a fuel pump if that proves to be the culprit.
Please make ANY comments. You guys are great.
- George