I've been slowly working on my 77 series that has a 1HZ in it. I get some black smoke when under load and the idle is somewhat rough on cold starts. The engine RPM is steady, but the the truck has a noteable vibration until it warms up. I know the 1HZ is gutless, but this thing is very slow. This lead me to think that the injectors are contributing to the problem and I needed to pull and test them. I also have a turbo/exhaust I'm plannng to install so I figured I should square away the injectors before doing that.
I have no history on the injectors, but the truck had 275k km on it. In all likelihood they could be original. The video attached shows my testing on all 6 injectors. They all seem to crack around 2000 psi, but some of their spray patterns seem very problematic. I have a new set of genuine Denso nozzles from High Tech in Australia that I plan to install.
Should I target the upper end of the spec for crack pressure (2200 psi)? Will the new nozzle add psi or should I plan to buy new shims to achieve the desired pressure? As it looks right now I'm 200 psi under the upper spec. Is there anything I'm missing on the injector R&R?
Okay, I went ahead and swapped out the injection nozzles. All of the crack pressures hit 2200 psi and the nozzles "chattered" at a much higher frequency. Here's the video:
I have no history on the injectors, but the truck had 275k km on it. In all likelihood they could be original. The video attached shows my testing on all 6 injectors. They all seem to crack around 2000 psi, but some of their spray patterns seem very problematic. I have a new set of genuine Denso nozzles from High Tech in Australia that I plan to install.
Should I target the upper end of the spec for crack pressure (2200 psi)? Will the new nozzle add psi or should I plan to buy new shims to achieve the desired pressure? As it looks right now I'm 200 psi under the upper spec. Is there anything I'm missing on the injector R&R?
Okay, I went ahead and swapped out the injection nozzles. All of the crack pressures hit 2200 psi and the nozzles "chattered" at a much higher frequency. Here's the video:
Last edited: