With the school bus setting in the shop, I see 20 psi at idle speed. At 1/4 throttle it moves up to 30psi then at 1/2 throttle to WOT it's back to 20 psi.
I replaced the overflow valve, fuel filters and lift pump. Still the same deal. Is this about all I can expect? I read that it's to be 35psi at WOT
I'm troubleshooting a low power issue on a 96 Cummins "B" Thomas Bus.
I pinched off the return line with both the old and new lift pump and the pressure went
I have a 30psi and a 60 psi liquid fill gauge w/snubber.
Perhaps I should shim the new overflow valve to 35 psi ?
Scott