Need help! - Cold Start Issue

I have a 1987 635csi that has developed a cold start problem. When the engine is cold, the motor cranks continuously but never fires. I am only able to start it by spraying ether into the air intake. Once the motor starts and warms up its fine.



I think I've exhausted all my troubleshooting steps, her is what I have done.



- Replaced the fuel with fresh gas.

- Ignition Tune-up (Cap, rotor, plugs)

- Replaced the cold start valve

- Replaced the ECU



Can anyone shed light on what else this could be?



Thanks!

Need help! - Cold Start Issue