Hello there, As the title says, I have a Bobcat T590 with a D24NAP engine. It will fire off with a shot of brake cleaner, and will run great the rest of the day but it will not start on its own. I have checked the injector fuel return (pinched/restricted flow), I am getting fuel to the injectors when cranking (cracked each line), and checked air and oil. Nothing seems to be out of place. No codes are being shown in the display. Does this engine fire injectors based off oil pressure, or is there a way to check fuel pressure without the software/adapter? Is there anything else that I may have missed while trying to identify this problem?
Compression check time. If your firing on starter fluid then that is the fuel part of the equation. Need to do a compression check on each cylinder.
The D24 Doosan engine is a high pressure common rail. There is no need to open every injector line. If one has pressure, they all do. And they are extremely high pressure. It is very dangerous to crack them open. The computer will fire the injectors (electronically) when the rail builds enough pressure. You need software to read the rail pressure. It needs to be above a certain PSI. Reason HPCR engine don't start are: They can't build rail pressure: slow cranking speed because of weak battery, faulty pressure rail relief value, leaking injectors, faulty rail pressure sensor, bad high pressure pump. If they are building pressure and the injectors are firing: then bad compression or glow plugs.
Thanks for the information folks! I am in the process of doing compression checks now. Fair points, knowing that now it seems I was a bit reckless with my diagnosing. Thanks for the tip however, will store for future use!
I often see this as being an injector problem, often one or 2 with high return. Try checking individual injector return flow, even while just cranking the engine over. Should be obvious if 1 has 3 or 4 times the return flow. There are specs for return flow, maybe someone can add those. Try removing the drive belt, sometimes this will increase cranking speed enough to let it build fuel pressure.