For a diesel engine to start from cold, it needs:
- Compression - this has been mentioned before, but if the oil was too cool, and coking of the ring lands was occurring, this will drop engine compression rapidly. A squirt of oil into the cylinder may improve compression figures.
- Air - If the valves are working and the air cleaner is not totally blocked (or in your case - disconnected) your engine will suck air into the cylinders.
- Fuel - Fuel of a high enough cetane, injected at the right time, into the hot air (heat of comprression) in the cylinder (or prechamber) will burn and the engine will fire.

Possible fail to start causes:
- Cylinder air temperature too low. Caused by dead GP or low compression/ valve leaks or Cam failure
- Lack of Fuel - a Fuel restriction would need to be total, to cause this, as the idle setting delivers only a minute volume of fuel to the injector.
Air in the fuel is a strong possibility.
- Lack of Fuel - damage to the IP caused by corrosion. Water kills IPs. If your oil is not guaranteed dry and if you do not have a water removal regieme and a water trap in the fuel system, after the fuel heater, you are just waiting for an IP failure.
- Incorrect Injection timing - generally would only happen if the timing chain were incorrectly set, skipped a tooth, or broke.

Failure to fire on starting fluid points strongly to failure to create adequate compression.
A compression test is the first thing you need to do. As others have already advised you. If there is any waiting to be done, you can remove of the rocker (cam) cover to confirm that the cam is intact ad rtotating with the engine. The valve clearances should be checked to ensure that they are within specification, to assist with the diagnoisis.

If low compression is found it will be on all cylinders (no firing AT ALL on starting fluid). Put some oil into each cylinder to determine if this is due to rings (compression will restore when the oil is added)

Please keep us informed of your progress.

__________________
Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.