[Grandad#3]

Well I was going to suggest the ignition switch module forward of the key. Mine went bad on me and I like to never found the reason for no start. It was like the car had a mind of its own. It would seem to start when it felt like it and not at other times.

Let start a NO START checklist

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Let's see what we need to start our cars. I am trying this off the top of my head so please correct or chime in with your experiences so it may help someone else.

Air/fuel/spark/compression
start by making sure we have a battery that is in spec.
all fluids topped off
no obvious broken wires and all vaccum hoses intact on visual inspection.
OK we have 12v at the battery with adequated cranking voltage we get in and turn the key.
12v from battery to ignition switch
12v from pin 50 on switch to pin 4 on dme plug (start signal)
12v on pins 1 (ignition pulse to ign. coil) and 18 (to G5 dme relay power supply)
12v pin 30 at dme relay (fuel pump power supply)
12v to pin 86 at dme relay in the run position (primary coil voltage)
12v to coil + black wire to ground 12v to - (green wire) to ground
12v to one side of the injectors
All ground contacts are clean
Fuel pump will run if dme relay is jumpered 30/87/87b
Fuel pressure at the rail is 29psig +/- 3 (jumpered 36 psig)
20 minute leakdown not under 14.5 psig
Fuel flow rate is 28oz after 30 seconds
Ignition coil primary resistance across + and - is between .4 and .6 ohms
Secondary resistance is between 5000 and 7200 ohms
Ignition wires are good no cracks or splits including coil wire and seated
Plugs are properly gapped
Ignition rotor is seated correctly with the set screw
Timing belt is installed correctly
Firing order is correct
Reference sensors are gapped correctly with .8mm clearance off the flywheel
Reference and speed sensors resistance checks in spec pins 8 and 27 speed 600-1600 ohms and pins 8 and 23 >1m ohm
Reference and speed sensors voltage checks 2.5 and 2v on oscilliscope (good luck)
Reference and speed sensor wiring is not broken at connector to sensor or to dme
Ok Im tired anyone else want to add or be more specific?

John_AZ
Do a compresion test.
Reference sensor tach bounce when attempting to start the engine. The tach bounce is very slight-1/16 of an inch. Clean connections as mentioned above.
Injector "noid" light. Very basic tool but will tell you if the DME is sending a signal to the injector. An oscilloscope is the best.
Clean connections at major parts like AFM, ISV, throttle body.
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Cheers,
Larry