Hi, I have a Isuzu truck with a 4HK1 which is common rail injection. The engine has a miss, i found that there is no fuel supply to the 2nd injector when it is missing but if i turn the truck off and back on the fuel is at the 2nd injector for a while until it starts happening again? Would this be the computer? or the common rail fuel bank? Anyone had anything similar? From memory this is a 186hp engine, so it may be in other machines aswell. Regards, Nick
Be careful playing with those things Nick, they develop ALOT of pressure - whatever it is I bet it will involve alot of $$ to fix. Injectors probably be around $1000.00 ea!! You will have to get some diagnostic equipment onto it & get it checked out ASAP
Hi, Thanks for the reply, there is a warning about it but when cracking the line it was just like a normal injected fuel line. Since there is no fuel getting to the 2nd injector i am hoping th einjector itself is not faulty. Can anyone explain how the distrabution rail works? is that where it get preassurised or is that done straight from the pump? i can not find a diagram anywhere. Regards, Nick
The pump pressurizes the fuel - so everything between the pump & the injectors (rail) contains constant high pressure ( 30 - 50,000 psi). Basically, the injectors have solonoids on them & they open & close the pressure to the piston. The engine management system times the whole operation & can hold the injectors open for as long or as little as required - This is why common rail is usually more efficient than an older mechanical injector system & why (combined with turbo;intercooler;etc) such amazing horsepower & torque can be generated from modern, smaller capacity engines. All the engineers have to do now is make them run as many hours as the old mechanical injected diesels do - difficult when the filter systems on the engines don't seem to be able to really protect the system Any contaminated fuel can destroy the pump & injectors - quick as a wink to save the environment - fuel companies have to remove sulpher & other properties from fuel - which lowers it's lubricity - & causes wear, so even without contaminated fuel - perfectly clean fuel from bowser is wearing it out I have an NQR 450 Isuzu - 60,000 Kms - engine when cold has unbelievable 'diesel knock' - dealer says new injectors req. - no warranty as this is wear & tear - 4 new injectors req. = $4,000 !!!! I have hesitated with this repair & used a fuel additive over the last 3 tanks of fuel & the 'knock' has almost disappeared. heres a link to help explain http://www.commonraildiesel.com.au/
Sorry for the delay, i fixed it the other day. I pulled the distrabution rail apart and cleaned it(had gunk in it) but that did not fix it. Swap injectors around and the problem followed the injector, replaced the injector($800) and the problem went away. The only thing i cant work out is how the engine managed to stop the fuel going to the injector when there is no electronics in the rail
I Nick, its prob to late now anyway, from what i have heard the newer Isuzu's have been having injector problems! (the ones fitted to the newer Hitachis anyway) Just a thought!
yeah i have been hearing of problems with the ones with tier 4 emissions standards, this one is tier 3 so manybe its no so common. Atleast it was an easy fix, but i dont like how they put the injector cabling in the rocker cover, its floating in oil which i know technicaly shouldnt have a problem but i dont like it. Cheers, Nick