Hey guys could use your help on this one. No service history and its a new customer. Vehicle is a 2014 Hino 258LP Flatbed tow truck. Complaint is that after a hot soak vehicle accelerates very slowly and has a severe lack of power. We were able to verify the concern when going over a steep hill and also when trying get on an onramp and once after coming to stop. No codes present and cel never comes on.

We recently got hino DX2 software. We are still figuring out the software so lots of its functions are new or unknown to us. We are able able to test the Turbo using the stationary test on dx2 where the engine is revved up and boost is supposed to be over 20psi. Test passed. We also monitored the desired and actual feel pressure when the problem occurred and they both matched. Visibly inspected exhaust brake for sticking and it's working fine.

Here's where things get weird. So on visible inspection the water separator filter was black and dirty. Customer does not know when filters were last replaced. This has a water separator filter and a fuel filter mounted near the driver's side of the engine. With over 300000 miles the customer does not have any recollection of ever servicing the fuel filters. The fuel filter mounted on the driver's side appears to have never been replaced. It still has the factory witness marks on it. So we recommended he replace both filters before proceeding with diagnosing. When we removed the filter mounted on the engine spin on driver side fuel filter we cut it open to inspect and found absolutely no fuel filter element inside. When I say nothing I literally mean nothing it was just a shell. Drive the vehicle afterwards and vehicle seemed to drive fine so we returned to the customer. After driving bout 60 miles he called and stated the problem still there.

My gut tells me we still have a fuel delivery issue even though desire matches actual.. We you really don't have any direction on where to go on this vehicle and would greatly appreciate some insight on what are some common issues or anything look out for on this system.

Miguel Moya
Technician
Scheidel's Fleet Service
Sacramento, California, USA