Cat c12 trim code locations

The last guys to work on my truck replaced the ecm thinking it was the problem. Turns out it was actually the fuel pump. I put a new pump in and bled the system and now it sounds like only one injector is firing while cranking. Could this be due to incorrect trim codes? All of them are set to 2300 as the default. I read somewhere that the trim codes are put on the injectors from the factory. If this is the case where exactly are they?
Thanks in advance

 

Also should be worth noting that all the solenoids work. Tested with cat et

 

Trim codes will not cause a no start condition. Trim codes are 4 digits on the solenoid body, all numbers on a C-12.

 

Fixed the trim codes. As you said still no start. Sounds like it's trying a little harder to start. I can connect to it using the diagnostic connector with cat et, and it doesnt throw any codes besides low coolant. I tried to use on board diagnostics to pull engine codes just for ####s and giggles and it said the ecm wasnt present. (MTVR, I'm a mech in the Marine Corps) however it still can pull up a hardware and software ID, just not when I try to pull codes for some reason. Also noteworthy that I haven't noticed on other engines is that I can prime it with the hand pump enough to where it send fuel through the pressure regulator into the return line.

 

Does your tach show about 200 RPM when cranking and what is your fuel pressure when cranking?

 

Thanks for your service. I remember seeing the MTVR in Iraq in 2003 (Army wheeled vehicle mechanic) and being jealous of the those. C-12 and fully independent suspension... Cadillacs!

 

She cranks at around 200 to 250 until it tries to start and then it goes up to around 350 while its cranking. Itll idle terribly for about 3 seconds and then die

 

And honestly for the amount of abuse the operators put on these trucks they handle it great

 

Is the original ECM back on it? Just curious about timing calibration on replacement ECM. Also, what lead to fuel transfer pump failing. Does the fuel look contaminated? Try running from Jerry can to see if issue with fuel lines or tank? Someone didn't manage to put Mogas in it?

 

Also, have you checked fuel pressure regulator in fuel filter base. Might be easy to swap from good running unit. Looks like hex plug with I think 1 1/16" socket fits.