SDP failing injectors

Could be a fuel pressure problem, check that the correct check valve is fitted. These engines run slightly higher fuel pressure as they supply fuel to the ARD head.

 

Check out my post on 8/9/13 [h=2]"Cat injector misfire under heavy load".[/h]It may be the answer to your problem

 

No air in return line under load, when the problem exists?

 

If the seat is warped, it can cause the needle to stick when under heavy load & high heat. When you pull the injectors, are they blue at all at the bottom of the injector to like halfway up?

 

I agree problems like that can be hard to troubleshoot. Dyno access would be ideal. Possibly extend your clear lines or sight glass and tie to the wipers so you can see it easier under full load.

I will send you a pm regarding the mxs I'm sure I can help point you in the right direction.

 

you need to check out that low pressure fuel system. you said you have changed all 3 check valves. any restriction on the suction side of the pump can cause air in your fuel from cavitation. If the fuel return line (to the tank) is blocked or restricted, very high fuel temperatures will be reached in the fuel manifold. Also if the fuel return line remains blocked to the tank, a build-up of air bubbles will occur in the fuel manifold. This trapped air will usually result in damaging injectors for cylinders 6, 5 and 4 (in that order) first. This is because trapped air in the fuel manifold occurs over these injectors first.
also the other poster trying to help you may be correct. A loose or improperly seated Unit Injector can led to injector failure. This also causes O-ring seals to fail and combustion gases to leak into the fuel manifold (Air in Fuel), which may cause damage to injectors "downstream" (also performance complaints such as stumble or rough running under load) is there any particular order in which they fail? perservere you will get to the bottom of it!