After much testing/adjusting etc... finally dug deep into component specs and cold start valve at fault. Clicked open with twelve volts BUT the resistance way down (3 ohms, not the the 11 or so it should) I speculate old age broke down the coil wire insulation - shorting out some windings. Anyway - high current draw as a result of low resitance was - I must assume - causing the relay to shut down too soon. ie; not enough fuel upon start up. Everything else was good - temp sensor, on/off ratio right around 48 or so, etc.
Anyway - hope that helps with anyone else dealing with this problem.
Cheers.