Hello greasytshirt,
After reading all 74 pages of this thread I have come to the conclusion you know WAY more than I thought I did about Hinos. If you're ever in Florida and need a job let me know!
But anyways I'm a fleet manager for a small fleet of 10 Hino 258s. 9 of them are 2007s and 1 of them is a 2008. I have had just about every problem you have mentioned in this thread and have come up with solutions similar to yours. Until today I had a 2007 258 come in to the shop with more oil on the engine dipstick than it had yesterday. I have had a faulty fuel line going to the injector leak before on other trucks but this time I can't "see" the leak. I took off the valve cover and still cannot tell which injector is leaking (which is my guess). My question to you would be how can I pressurize these injectors and check for leaks? Can I run the leak check with the valve cover off? I have the hino diagnostic explorer software and bowie box. Do you have another method to check for fuel leaks inside the engine? Is it the injection pump leaking somewhere!??
Again thanks for all your valuable information,
you should get paid for this!
And if I need to pay you please let me know I will.
Thanks!
Carlos Rodriguez
239-403-0000
Excellent questions!
Find this short line on the engine. It's the fuel return from the injectors. You're gonna want to root through your magic bolt bin and find a piece of an old return line. Connect one end to the rocker box (the horizontal bolt), and the other to a regulated air supply. 30-40 psi max. With the valve cover off, squirt oil over all of the banjo bolts and at each seam at the line. You should see bubbles if it's leaking. Frankly, the fuel return line under the valve cover, the special banjo bolt, and the sealing washers should NEVER be reused. That one banjo bolt is a one time use thing. And the torque on all of the banjo bolts, including the special one, is only 110-115 inch-pounds. If anything is leaking, replace the line, the special banjo bolt, and all of the seal washers. The injector banjo bolts can be reused.
If the fuel tank had ever been pressurized to help prime the fuel system, there's a possibility that the shaft seal on the injection pump has blown out. It is not serviced separately. You'll need a replacement pump.
Another method is to get a big bottle of UV dye and dump it in the fuel tank, then run the engine while looking at everything with an ultraviolet light and yellow glasses. I've used this method to find fuel leaks in crossover lines in 6V53 Detroits in the M113A2 APC.
If either of these methods yield results, I'll reveal my paypal email. Donations are accepted, but not required.
Edit: Where abouts in FL? There's one fella on here that's had a hell of a time with his Hino, I talked him through a lot of it. If you two are sort of nearby, I think he'd definitely appreciate someone with experience being in his corner.
