Need some help 2011 Volvo 740 with ISX (deleted) I stopped at a red light and when I went to take off heard a squeal and at the top of the gear the truck wasn’t getting boost from turbo. Truck is not receiving any fault codes and checks are made by Cummings software computer. I have replaced the actuator, manifold back pressure and boost pressure sensor. Charge air cooler has no leaks Exhaust down pipe is clear Manifolds are all clear Fuel system is clear VGT moves freely by hand on turbo No cracks found during inspection Checked all wires, voltages and connections Turbo spins up to 35k RPM and actuator goes up to 90% and sets at around 70% on highway test with truck going 70-73mph Manifold is only getting 2.9 pounds of boost. Anything thing else to check or suggestions? Pretty near the end of the rope on this one. Thanks in advance
There is an open connection to feed filtered air from the turbo into the air compressor. It is a standard thing to check when looking for a turbo pressure loss especially if the loss is only at higher pressures as a hose can split and still seal up to 5 to 8 pounds pressure.
