Truck will start with ether but will not run on its own. At first it was getting fuel to the fuel rail only while the starter was engaged. Solved that problem but still wont run. Replaced the Circuit Opening Relay, Main Fuel Injection Relay, rebuilt and tested the fuel injectors, tried a second ECU and through it all the problem has not changed. I have not checked the fuel pressure at the rail nor have I been able to check the signal at the fuel injector itself to see if the problem is in the electronics there. Please help with any ideas to troubleshoot.

 

Borrow or buy some noid lights to check if the injectors do get the pulse to open like they should.

Just how did you get here?? This is a big help and can point in the areas to look at.

using the wrong injectors for the ECU you have

Open Solenoid (injector) resistor

Just where did you get your new relays? some real poor quality knock offs floating around Did you test them before installing??

Did you mean the EFI relay or are you running a custom fuel pump circuit?