make sure you have 12+ volts at the red wire,,the green and blue are pulse wires and will need a noid light to test or a led style test light with a + and - lead..check this first,,it you have 12 v and you have pulse width move on the your distributor..this had to be spot on to fire the injectors,,if the ecm do see it then it wont fire them..

Hi, problem has been solved !

Because I had no tach signal, started looking for wire colours at the distributor etc. It has a 4 pins connector but also the iac valve has a 4 pins connector and almost same length of wires... so connectors have been switched during rebuilding

Switched connectors and engine fired up right away !

With diacom, I putted ignition in base time setting mode and adjusted initial timing. So far so good, but when looking at the fault codes code 42 appears (and cant't be cleared for more then 2 sec as it returns)

code 42 : "electronic spark timing malfunction"

So what's next to replace or to look for?

Thx for all usefull info !

regards peter

Glad to hear that you are making progress. You may have damaged the ignition module when you connected it to the IAC harness. Or worst case the ECM might be damaged. Try a known good ignition module (you mentioned you had a spare distributor) and see if the code goes away.

GF?

I recently had this same issue on my 95 Silverado 350 TBI I replaced every thing and still no pulse to injection wire's I put 2 new pickup coils' new fuel pump ,new distributor, and much more just to recently find out my only issue of my injectors not getting pulse with the pulse light was ( the ground on the bell housing next to the distributor)I fixed the ground wire and reattached it and it fired right up I hope this helps you guys with your problem!

I know this is an old post but wanted to ask about this problem since I'm currently have the someone. Can you tell me how you fixed your tach issue that was causing the no start problem?

Thanks!

Sounds to me as he mistook 4 wire iac connector for the 4 wire distributor connector.