Detroit 14 L DDEC 5 - no power on hills, after inframe.

Just did the inframe in a local shop with reputation. They do many overhauls on Cummins, CAT and Detroit. The truck does not have enough power on hills even with 25 000 pounds in box. The air temp sensor and the turbo boost sensor were replaced. Rebuilt injectors were installed. After replacing the fuel temp sensor, I have the feeling that the truck runs little bit better, but still no power on hills. The turbo boost goes to 30 max, but I remember before was going up to 35.

Friend of mine suggested, it could be the VPOD - this thing is connected to the truck computer and supplies air to the turbo actuator. But if the VPOD is bad, I should get code 39 right?

I plugged my laptop with DDDL 6.5 and NO CODES!!!

I am thinking maybe the timing is off by some teeth or the injectors are wrong.

These are N3 injectors, are they different types? I heard for some engines that have injectors with 3 different timings that look exactly the same and you have to match them by serial numbers?

Another friend suggested, maybe the fuel side is sucking air from somewhere or you have restricted return.

 

How do I check the fuel pressure? What type of gauge and where to put it on?

 

What should be the normal fuel pressure at 1800 rpm?

 

No leaks anywhere, done the test spraying soupy water. It comes down to 2 things. If the fuel pressure is low - the check / regulator valve on the return line is bad. If the fuel pressure is good, have to test the VPOD, what pressure is going to the turbo actuator.