Who the hell came up with the idea of a sideways mounted distributor stuck right into the oil gallery of a cylinder head?
To be fair, I knew this particular bit was in need of replacement. It already leaked oil onto the transmission bellhousing just below due to a worn distributor shaft, I just wasn't in any particular hurry to get a new one since I rarely drive. What I didn't expect was what the distributor/crank position sensor would do, besides getting the cap and rotor a bit wet. It started with a fuel problem that would alternately produce flooding and low pressure from the pump, killing the car either immediately or shortly after movement. This seemed like an obvious fix. A new regulator and the pump was now producing consistently low numbers on the fuel pressure gauge while refusing to prime at all on some occasions. I was suspicious, so before dropping upwards of 200$ on a new unit, I took a trip junkyard for a cheap pump I could try for confirmation . (I broke it and cannibalized the two, but that's another story.) Right about that time the power to the fuel pump stopped working altogether. This led to the obvious checks of wiring, relays, fuses and fusible links for a few hours until life interrupted and the car sat a while longer. Nothing. Looking over the wiring diagram for this car, I noticed that the fuel pump relay was actuated by the ECM, the only part I hadn't checked before. $#!@.
Out from under the seat came the control module. With the key turned to 'Run', the two LED's in the ECM remained unlit. This was a bad sign, but not fatal since there were several possibilities besides a fried EPROM/power transistor/Other-Very-Important-Part. A few more power circuits, ignition signals, fuses and fusible links later and, fearing the worst, I swapped in the old PCM from before the manual transmission swap. The same blank stare from the LED's stared back at me accusingly.
Going back to the diagram, I noticed that the ignition coil and it's accompanying power transistor were linked directly to the same power circuit as the ECM, so of course I began poking multi-meter probes into it's guts. At this point I found something shorted (not sure exactly which wires) that disappeared soon afterwards (this is going to haunt me later). I don't remember what prompted me to unplug the crank position sensor and turn the key one last time but when I did, I was greeted with the Christmas themed ECM lights blinking cheerfully at me. Maybe I should have thought of this sooner.
Now, I had known that a bad crank angle sensor could cause stalls, no start and some very rough running but it's the first time I've heard of one behaving in this peculiar way (cutting off power to the ECM in an indirect sort of way). In hindsight (now with highlighting!), it should have been more obvious.
1/19 Note: Leaving the key in the ignition and wiggling the harness/disconnecting parts until relays kick on or the ECM lights up is a good way to troubleshoot something like this.
