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There are lots of possibilities for a no-start condition.
Please take a cruise through the 700/900 FAQ (upper right pull down menu) for possibilities and testing procedures. I'll try to list a few of the more common ones in order of testing ease/likelihood. BTW a 1990 740GLE will have a 16-valve B234F with LH 2.4 ECU and EZ-116K ignition.
The first thing to do, and without getting dirty or dragging the tool kit out, is to check the ECU (both fuel and ignition side) for stored diagnostic trouble codes. Refer to the 700/900 FAQ section on OBD Diagnostic Codes for procedures. Print that section out and take it with you. Read out all the codes on socket pins 2 and 6. One distinct no-start possibility I can think of is a 1-4-3 code on port 6 (ignition) or a 1-3-1 code on port 2 (fuel ECU) indicating the crank position (rpm) sensor signal is missing. See notes below.
Normally I'd say to remove the oil filler cap and do a quick check to ensure the timing belt is okay by cranking the engine to see if the cam rockers move, but a) it's just been replaced and b) the B234F is an interference engine so cranking would cause the valves to hit the pistons.
Do an initial check of the fuel pump. You should be able to hear the main fuel pump briefly buzz for a moment to pressurize the fuel rail when the key is turned into the on (KPII) position. If not: possible bad fuel pump relay, bad ECU or (less likely) fuel pump.
Check for spark. Remove a plug (or pull a wire and put in a good used plug). Gripping the plug boot with a wrapped rag so you don't get zapped, hold the electrode (base) of the plug against the head/block while cranking the engine. No spark indicates it's on the ignition side. A strong, crisp spark means it's on the fuel side. A weak spark could mean the distributor cap/rotor or coil. Refer to the FAQ for details.
Check for fuel. After cranking, remove a spark plug to see if fuel is getting into the cylinder. Is it wet with or smell of fuel? That would mean the fuel side is working. If it's dry then you work your way up the fuel side. Ideally you would do a fuel pressure test at the fuel rail, but you can carefully open a line and point it into a jar to check for fuel flow during brief cranking. As noted above, no fuel likely means a bad FPR (relay) or ECU. Relays are easy to replace and relatively cheap (esp. used ones). ECU's, not so much. Unfortunately, LH 2.4 ECU's of that vintage (as used in the 1989-1990 B234F's) are known for blowing their fuel pump control circuitry. Further details are in the Engine FI and Ignition Computers section of the FAQ. You can access the relay tray (with effort it unclips and pulls out) and carefully jumper the relay pins to temporarily bypass the ECU and the relay itself. It's in the FAQ section referred to above.
As mentioned, for a no-start be very suspicious of the crank position (rpm) sensor. It's not at all uncommon. The engine won't start if there is a missing or weak signal. Often this begins as an intermittent hot no re-start. This is typically caused by a damaged cable exposing the internal braided shield to allow electrical noise, metal contact or moisture. Not infrequently you'll find the cable cracked at the base where it goes into the sensor. As I recall, the sensor can still be faulty without raising a diagnostic code if the sensor is producing a weak signal. Once you've eliminated other simple possibilities it would be worth removing the sensor for inspection (the cable starts on the firewall going down behind the block to the sensor mounted on the top of the bell housing). For a regular B230F/FT the sensor is relatively easy to remove. Stand over the exhaust side and drop a 1/4" drive 10mm socket on a couple of long extensions behind the valve cover. You can then reach under the intake manifold to lift off the bolt and carefully twist the sensor up and out. Something in my memory says it wasn't as easy with a B234F, but I may have attacked it from the wrong side. On re-installation be sure to put it back in the standoff clips (or wrap it in a slit piece of rubber hose) to keep the cable from chafing against the water pump return pipe.
Hopefully between the FAQ and the above suggestions you'll find the problem quickly.
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Dave -940's, prev 740/240/140/120 You'd think I'd have learned by now
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