Im dead in the water. So any help would be awesome.
I'm looking into a 2016 mack cabover/dump body has a mp7 engine.
Truck has the one code and stalls out (within a 10 minute test drive). Starts and idles no problem. Idle fuel pressure is between 45-50 and tops out at 80-90psi at 2000 rpms standing still.
During the first few minutes of the test drive the pressure sits around 35-45. Never can get past 35mph and fuel pressure will drop to single digits.
So far I replaced the left side near the front head regulating check valve, one other valve at the filter housing, both fuel filters, and fuel supply pump.
Disconnected the return side fuel line at the tank and after a couple minutes found no air in the bucket. Although the stream seemed kinda weak, but I'm not sure what is normal for it. No stream at 2000rpms.
Took off the filter at the engine and primed the system and it was getting a good amount of fuel out of the housing.
Again any help is appreciated:)
