Hi all Got an odd one The 2011 GMC Acadia came in for an engine replacement the engine that I have installed is brand new all sensors and etc have carefully been removed from the old engine and reinstalled back on new Engine including fuel rails, injectors, high-pressure fuel pump there were no previous issues with fuel pressure before the engine swap. Fuel pressure at test port is 50-68 PSi and my scanner confirms this with the fuel pressure switch reading that there lies the issue even running it still only shows same pressure as the test port and at idle it should be 500+ psi Desired fuel rail pressure at Idle show around 518psi but this case in pic 551 psi only getting same psi readings as the test port. Did my fuel pump go down during the engine swap or would even a small injector leak cause this? I would think even with a leaking Injector it would run way higher

than the test port psi. Any help is much Appreciated Cause I do not want to spend 400 bucks on a fuel pump to find out it was not the issue.fuel pump I qestion is the high pressure pump the head driven off can lobe

Are the trims running rich?

yes the fuel trim was maxing out on the positive side both banks

Did you transfer the cam follower for the hi psi fuel pump from the origonal engine before installing the fuel pump?.I have seen that done before?

wow thanks, I believe you just found my problem thank you I will update when I get it going thanks again

Sorry for the delayed response yes that was it well that and injector leaks I told my boss when changing the fuel rails over the o rings was meant as one time deal I told him to invest in the two rail kits to rebuild injectors but no he said I done cut too much of a deal on the job and I am not calling to add to his bill well that BS cost me a week waiting on the rail kits because Like I told him they had to be replaced but anyway Thank You dpieroni3