Valmet 860.3 starting problem

Hello guys,

I would like to know if any of you could help me out with this one, my Valmet 860.3 (2007) is having problems when starting, i start ignition and the machine takes almost one minute to fire the engine, after fireing up the engine it works normally, but if i stop and wait 10 minutes it takes about 15 seconds to fire up the engine again. If i fire the engine one hour later it takes again almost one minute to start.

Have anyone experienced this? If someone could give me a clue i would appreciate.

Lift pump starts when i turn on the key, i wait until standby of lift pump and the problem occurs. it gives the impression that fuel goes back.
Exhaust starts releasing smock some second before the engine fires up.

BR

Hi,
It sounds like it could be a fuel related problem.
This is beyond my own skills, but have you visually inspected e.g fuel filters on the motor block?

I hope that someone with similar problems can help out.

Hi,

Fredrik Reuter, thank you for you reply.

I will check fuel filters tomorrow again, but i dont beleive the problem is from there. I´ll leave a reply here for future similiar problems.

Check the fuse and function of the electic preheater element in the intake manifold on the engine.
You have the big fuse and big relay to this nearly the intake manifold. This function will be activated automaticly for only some second when you start the engine from the ECU. If this function not run like it should, you have problem also in the summertime like you explain.

You may have a " one way" fuelvalve on the fuelline near the filter, if this gets stuck fuel can seap back into the fueltank when engine is not running.
It happened to me with a1270d. ( dont know if Komatsu have the same system.

Thank you for your replys.

According to what i've been studing, I believe my problem is with the common rail overflow valve.

I think there isnt enought pressure on the rail to ignitiate the injectors, cause of the overflow valve that is leaking to the tank, even with the engine stopped it remains leaking.

According to what i understood about common rail, it has to achieve "x" pressure to ignitiate injectors, and it takes so much time to start/fire up the engine cause of the leak, fill up rail again, etc.

I also read that those valves are a little bit problematic. Symphtoms are hard start, loss of power (the last one i havent experienced cause the machine is new in my hands).

So tomorrow i will replace that valve. I hope it works