WARNING: DiD PISTON FAILURE DUE TO FAULTY INJECTORS
Posted: Thu Feb 06, 2014 3:36 pm
From Entabeni: 2006 Pajero 3.2 DiD LWB GlS Auto Gen3.
As far as I can establish piston failure is a common problem with these motors (as well as some Isuzu motors). The cause appears to be 'over-fuelling' by the injectors when they grow "old", i.e. over 100,000 km. Then a very hot (and possibly off-centre) flame can develop which over-heats the point it strikes to the extent that it can melt the alloy. Furthermore, a specialist diesel and turbo firm in Worcester says that they have seen pistons completely shattered by explosive burning caused by over-fuelling. This may well explain the 'pinging' sound which I and others on the Forum have heard.
These direct-injection injectors have to cope with the extremely high pressures of the burning mixture during the power stroke and are mechanically complex. They say that the various operating pressures on mine were way out. It cost just over R 4000 to have them reconditioned! Nevertheless, take action before you find yourself stuck in some remote place, for that would cost a lot more! It is just damned lucky that mine failed 20 km from home so that I could drive it back without further serious damage.
With mine stuck in a carport behind our house in Robertson I have relied on the Haynes Repair Manual for Pajero models 1997 to 2009 to guide me. In the section dealing with possible repairs with the motor in the vehicle, they include removal of pistons. It has taken me four weeks to get to that point, even though I have done this kind of thing many times for more than 50 years with a variety of more conventional petrol vehicles! The Haynes manual does not get everything right and glosses over many procedures that require cranked spanners not to speak of cranked wrists. Difficulty of access is the main problem. I will post further items on the Forum, with photos, describing some of the procedures. Meanwhile here are some photos of my failed piston No 2 with its crack and possibly a minute amount of melting. (Have failed to upload them --- will try again)
Finally, does anyone have new pistons for sale?
Entabeni.
As far as I can establish piston failure is a common problem with these motors (as well as some Isuzu motors). The cause appears to be 'over-fuelling' by the injectors when they grow "old", i.e. over 100,000 km. Then a very hot (and possibly off-centre) flame can develop which over-heats the point it strikes to the extent that it can melt the alloy. Furthermore, a specialist diesel and turbo firm in Worcester says that they have seen pistons completely shattered by explosive burning caused by over-fuelling. This may well explain the 'pinging' sound which I and others on the Forum have heard.
These direct-injection injectors have to cope with the extremely high pressures of the burning mixture during the power stroke and are mechanically complex. They say that the various operating pressures on mine were way out. It cost just over R 4000 to have them reconditioned! Nevertheless, take action before you find yourself stuck in some remote place, for that would cost a lot more! It is just damned lucky that mine failed 20 km from home so that I could drive it back without further serious damage.
With mine stuck in a carport behind our house in Robertson I have relied on the Haynes Repair Manual for Pajero models 1997 to 2009 to guide me. In the section dealing with possible repairs with the motor in the vehicle, they include removal of pistons. It has taken me four weeks to get to that point, even though I have done this kind of thing many times for more than 50 years with a variety of more conventional petrol vehicles! The Haynes manual does not get everything right and glosses over many procedures that require cranked spanners not to speak of cranked wrists. Difficulty of access is the main problem. I will post further items on the Forum, with photos, describing some of the procedures. Meanwhile here are some photos of my failed piston No 2 with its crack and possibly a minute amount of melting. (Have failed to upload them --- will try again)
Finally, does anyone have new pistons for sale?
Entabeni.