I have a 1989 760 Turbo with 205,000 miles. It will not start from cold. It has no spark. I can’t figure it out but here’s what I’ve tested this far. Also, I got a junkyard dist because I thought it might be the hall sensor. No change.

1. Coil Spark Test. Took my spark plug look-alike spark tester. Hooked to plug wire and hooked plug wire to coil – grounded.

Fail. No spark.

2. Coil test. I have a coil tester. When hooked up – it sparked.

Pass. Coil is good.

3. Switched the two black under hood relays.

No change. Car did not start - no spark. Both relays COULD be bad but not probable.

4. Cleaned all grounds and terminals.

No Change.

5. Checking Power supply i.e. fuses, wiring etc. : Tool = Test Light. Check coil term #15 (+) and #1 (-) with key on II Pass equals test light bright. Light dim #1 (-) is check for powerstage. Light off is a fail. Items for failure power stage, all wiring and their terminals, ignition switch.

Fail.

6. Checking for Coil Grounding Impluses (The computer grounds the coil to energize the secondary spark). : Tool = Test Light. Check coil terminal #1 (-) crank engine. Pass equals a flashing test light. Fail is no flash. Items for failure are Hall sensor in distributor, all wiring and terminals, and the ignition computer.

Fail.

7. Checking Computer impulses at Powerstage: Set meter for 2.0v scale, no buffer. Roll back the rubber boot at the powers stage connector. Probe with meter positive test lead to #5 gray wire, crank engine, voltage should oscillate between 0.8v to 1.8v. No oscillation is hall sensor fail.

Pass. V reading was not .8 but rather .008 to 1.8/9. The hall censor was oscillating. No surprise, I didn’t think I had two bad hall sensors.

8. Test #1 terminal with a dim light, for powerstage test: Key off, disconnect powerstage, Key on, check coil #1 (-) Bright test light equals dead powerstage. If the light is off or dim the wiring or a terminal is grounding the circuit.

Pass. No light at all.

6. Fuses: Check fuses 1, 21, 30, 31 and the wiring connections in the fuse panel.

This was the final test. Everything passed except for when I tested #21. 21, on the panel, says Glow Plug Time (I don’t have a diesel, though), Relay and engine control. If I grounded my tester to the door, it would light up but it would not light if I made a complete circuit to the fuse panel. It would not light at all. What does a ground problem like this mean or is it just a symptom of another problem?

Any help would help.

Thanks,
Doug