I recently posted a tab about my 2001 Blazer not starting and after much debate I decided to go ahead and upgrade my old factory Spider CFI injection with a new multi port injection spider, even though my Blazer was holding good fuel pressure and ran great after giving it a shot of starting fluid. Anyway, now here's my problem. After installing the new MPFI my Blazer fired right up and ran great, for about 200 miles. Then all of the sudden it just shut down at about 60mph (going down the interstate) and since will not start. I hit it with a shot of starting fluid and it fired right up and would stay running as long as I kept spraying fluid, so it has good spark. Then I checked for fuel pressure, it has good fuel pressure and is holding good pressure when turning off ignition. So I figured that I bought a faulty MPFI unit, so I replaced it with another brand new one, I'm still having the same issue. I guess my injectors are not getting a signal to fire or pulse. I know there is a fuel pump relay but is there also one for the injectors? I've check all of the fuses and they seem fine but is there a fuse for this system? What exactly signals injectors to pulse? At this point I am lost, any help in this matter would be great! Thanks in advance.

 

At the top of this sub forum, there is a thread that explains how to check the fuel delivery system. Post all 4 readings and we can analyze them. Or we can keep guessing, your choice