6NZ low power question

I have another quick question regarding the injectors. Did you start the engine on Starting Fluid while trying to prime the fuel system?

 

Did the engine still sound fine while it was running if all 6 injectors were scored? How would them being scored effect performance of them dramatically? With them being scored it just doesn't allow them to build the proper pressure?

 

Think about what you said if they can't build and maintain the proper pressure to open the tip because the fuel is bypassing the plunger flow through the tip will be reduced.

 

I should have paid closer attention to your first post. When I posted about the injectors, I was thinking you had the original six injectors. Since you replaced one of them I doubt you have scored the barrels and plungers. One strong injector in the set would cause the engine to run rough. In my post all six injectors were damaged, so the engine ran smooth and would pass an injector cut out test. Once #1 and #2 injector were replaced, the other 4 weren't moving an equal amount of fuel this caused the engine to run very rough at idle and misfire under load.

When you did the cut out test, was the mm of rack travel high? They can be even and pass, but if it takes a large amount of rack travel to do the test then its a possible sign that the injectors aren't flowing the correct volume of fuel

 

1) yes

2)the fuel bypass the plunger and the pressure doesn't rise at the tip to open it or keep it open for long..........the needle is raised off the seat of the injector tip by the hydraulic pressure created with the plunger coming down into the barrel. If the hydraulic pressure of the fuel can't be raised high enough or be maintained high enough to keep the needle in the raised position once fuel starts exiting the injector tip..........fuel stops flowing into the cylinder, regardless of what the ECM is telling the injector to do.

3)yes

The one thing you have to remember is these injectors are more mechanical than they are electronic. 99.999% of injector failures are in the mechanical portion of the injector, not the electronic portion. The only thing the electronic solenoid and actuator assembly do is to stop the fuel from returning to the fuel galley in the head once the ECM decides it want to fire that injector. The actuator assembly will modulate once the pressure rises inside the injector body above the pressure required to lift the needle from the tip seat, again this is a mechanical function of the injector. This in turn controls the internal pressure inside the injector body and keeps the tip from being blown off from excessive hydraulic pressure of the fuel.

This knowledge and understanding of how an injector functions comes from a person with much experience in rebuilding these injectors........his insight in this area is very valuable, but is highly misunderstood by many in my opinion, unfortunately.

 

Thanks for the breakdown!

 

have your wastegate adjusted to 18.9 instead of 18.1
another thing i have done to mine is take a couple of 1/4 inch washers and put them between the wastegate and the wastegate mount . just back the bolts off very carefully and put washers in . you may have to cut the washers out to get them in but it works good i went from 24 to 34 pounds boost and better jake too . it delays the opening of the wastegate it doesnt dump the boost as quick