EST wire connected issue

[budweiser_man]

1974 chevy K5 blazer truck
1991 Chevy K5 blazer 350TBI motor
SM465 and 205
Wiring from same truck
EGR deleted from wiring harness

Problem: truck will start and run for about 1 second than die with EST wire connected. truck will start and run with wire disconnected.

things I have noticed or tried:
tach drops as soon as it starts, fires and dies right away connected. I have back probed the ECM with a fluke meter and I have the pin out with the voltages I need and from what I can tell they are all correct. grounds where they belong and voltage where it belongs.

When trying to start I tested the wires going to the distribtior and got the voltages i needed from the 4.5 across the EST wire, 1.5 on one of the other wires, black/red wire is ground and it ohms out to ground with less that 20 ohms when key is on and about 2-3 ohms when key is off.

Wiring harness looks good no breaks or ground issues.

I have tryed a different ESC and spark advance inside of the dizzy.

next when the truck is running with the EST wire disconnected and I plug it back in the truck will contune to run just fine.


Idea:
Is it ok to have 20+ ohms on the black/red wire when starting, I did try to ground out this wire and no difference when trying to start.
it is acting like the truck does not know it has started and is ok to run.

[Six_Shooter]

What are the injectors doing when the truck stalls, do they stop before the engine stops or as it's stopping?

20 ohms is fine, you will never see 0 ohms on that wire, due to how it's connected through the ECM to the vehicle.

[budweiser_man]

the injectors counuine to fire for a split second after it sounds like power was cut to it.

[EagleMark]

Check wire A6 that it has power from key on, to crank and back to key on always till key off.

Check wire B1 and C16 have power always, key on and key off.

[budweiser_man]

ok thanks! I will give this a try tonight

[budweiser_man]

A6 is on when key is on and cranking, B1 and C16 are always on key off on crank

really dought timing issue due to it starts so nice when disconnected.

would the computer be trying to advanve the timing too much for it to start. and what does the computer use for a reference to 0 or ground on the EST wire