how do i test the ECM the fuel pump is not working and the injector is not injecting

1st have you checked all the fuses and relays...

yes i have replaced all!!

Please supply information.

Year, engine, model

it is an 84 I started with 1.9 and changed it over to a 4.3 tbi it work great. Then I slung a rod so I am now putting a 4.3 cpi any help would be great thanks!!!

tbi came out of a 92 blazer cpi came out of a 94 blazer. I had the whole truck so wires were not a problem

well, you will need a new fuel pump and the complete wiring harness from the 1994 for this truck to fire up.

you cannot use a TBI pump on a CPI engine.

You need to get a CPI pump.