have 1988 Chevy K1500 does the ECM work will trying to start motor or after motor starts does Ecm start to work then? have fuel up to throttle body but not going thru injectors and no spark, every thing i have replaced in ignition system ecept ECM.

 

the ecm is the "brain", without the brain the engine does not know what to do, therefore if not working correctly it will crank but not start, I am not saying that is the problem, it could be several things, first thing I have to ask and I don't want to sound like a broken record but have you checked the fuses?

 

yes have checked them i have 12.79 v at coil and it goes into ignition control mod in distributor pickup coil and ignition mod both have been replaced new. Have no spark and no fuel pulse at TBI. is the ECM in Use at Startup Or does it Jump In After engine Starts? Also The Spark Control Modual Next To TBI What Is Its Function In all Of This?

 

What motor size do you have? I will post a starting diagnosis procedure for your vehicle from the manual.

 

5.7 tbi

 

Well, this is what the book says in your case, if its in the distributor, but I see you have a new one in there & have tried this.

Engine Fails to Start

1. If the engine won't start, perform a spark test as described earlier. If no spark occurs, check for the presence of normal battery voltage at the battery ( BAT) terminal in the distributor cap. The ignition switch must be in the ON position for this test.
2. If battery voltage is not present, this indicates an open circuit in the ignition primary wiring leading to the distributor. In this case, you will have to check wiring continuity back to the ignition switch using a test light.
3. If there is battery voltage at the BAT terminal, but no spark at the plugs, then the problem lies within the distributor assembly. Go on to test the ignition coil.

and the coil test..

1. NOTE: These resistance checks will not disclose shorted coil windings. This condition can be detected only with scope analysis or a suitably designed coil tester. If these instruments are unavailable, replace the coil with a known good coil as a final coil test.

Fuel Injected Engines

1. Tag and disconnect the distributor lead and wiring from the coil.
2. Connect an ohmmeter as shown in Step 1 of the accompanying illustration. Place the ohmmeter on the high scale. The reading should be infinite.
   
   
   
   <CENTER><TABLE cellSpacing=0 cellPadding=0 width=400 border=0><TBODY><TR><TD align=middle>Fig. 1: Fuel injected engine ignition coil test
   
   
   
   </TD></TR></TBODY></TABLE></CENTER>
3. Connect an ohmmeter as shown in Step 2 of the same illustration. Place the ohmmeter on the low scale. The reading should be very low or zero. If not replace the coil.
4. Connect an ohmmeter as shown in Step 3 of the same illustration. Place the ohmmeter on the high scale. The meter should not read infinite. If it does replace the coil.
5. Connect the distributor lead and wiring.

 

Sorry to bring this up from the dead but did you find out the problem??? Same thing is happening with a nissan I have that we put a rebuilt motor in and no mechanics can tell me whats wrong?