Everything is stock except for that vent line, there are two rubber lines that come from or go to the inline injection pump depending on how you look at it, one of them lines is the injection pump control line that goes from the throttle body to the injection pump, it is a vacuum line that is controlled by a venturi in the throttle body, when the butterfly is closed in the throttle body while the engine is running that venturi creates vacuum in that line which pulls against the diaphragm spring bringing the injection pump to the idle position, now you must understand that the diaphragm spring in the injection pump wants to be in the floored position when there is no vacuum, the other line is the vent line that basically goes to the airfilter, the air in that line goes back and forth just enough to let the diaphragm move back and forth, so what I did was tap into the intake tubing between the turbocharger and throttle body and I put that vent line there along with the line going to the boost gauge, so when under boost the vent line is under boost, but the injection pump control line is also under boost, so when one has their foot deep into the pedal the diaphragm spring wants to be floored, but when you let off the pedal the venturi in the throttle body creates a lot of vacuum pulling the injection pump back to idle.handcannon wrote:I for sure will be waiting anxiously for when you make that diagram so I can know just how you plumbed the lines. I can attest to just how difficult it is to picture how you plumbed the lines for a successful turbo install. When you do get the time to diagram the install please note the direction of flow for the air, or vacuum.
Don
If the butterfly in the throttle body is only a little open, the venturi creates less vacuum so it only lets the diaphragm move a little towards a richer position, if I didn't pipe the vent line to boost, the injection pump would be floored most the time because of boost, and the engine would run very hot EGTs(exhaust gas temperatures) because of being rich all the time which is the issue I was having with the 720 turbodiesel when it was piped as a blow thru, it ran stinking hot all the time.
It's complicated, but it is not complicated as except for the turbocharger being there all the lines except the vent line are not changed, only the injection pump vent line is piped to a boost source and it sees boost when there is boost same as the injection pump control line, when there is boost it sees boost, so when there is boost, both sides of the diaphragm see the same boost and cancel each other out, so then the venturi in the throttle body works as it should.