1988 3VZE won't start

[mechatater]

Driving on the highway recently, the engine momentarily cut out and came back up with a jolt. Happened a few times over the course of a little more than a week. Code read loss of power supply, but clearly intermittent and I couldn't diagnose it. Then about six weeks ago, while slowing to a stop, the engine died and wouldn't restart.

After towing home, I checked the voltages on the ECU and then the resistances on the cables coming to the ECU. Nothing out of order.

I previously had a code for a bad knock sensor (right after passing smog), so I took the time to replace the knock sensor and cable (no connector corrosion and the cable was intact). While torn down, I took the time to check all of the relays' operation, resistances of sensors, injectors and on various parts. The only item with a bad reading was the cold start injector resistance (very low; don't know why I didn't see this at the ECU cable). Wound up replacing several tired or split hoses and all of the injector connector bodies. I haven't yet replaced the cold start injector.

All put back together and the engine almost catches on occasion, but never starts (this could partially be the cold start relay, but the temps were in the 60s when I tried starting it). Loosened the cold start injector fuel line and got a spurt of fuel, so the fuel pump is delivering fuel to the rails. Triple checked all of the vacuum lines and connectors.

I'm stumped, unless the loss of power supply has potential sources not in the manual's troubleshooting section, or simply a spotty ECU. Bad harness?

Any helpful thoughts?

 

[Ahlem]

When you pull the middle wire from the distributor cap and arc it to something when you crank the motor, do you have spark there?
What is your fuel pressure? I'm thinking one of the basics of fuel or spark is causing your problem. Possible dead fuel pump.
Check the fuse for your fuel pump and pull all the fuses and relays one at a time and put them back in in case you have coastal corrosion screwing with the electrical connections. Will it kick over if you spray starter fluid into the intake at the throttle body? If so, that really aims you to a fuel supply issue.