03-07-2018 10:23 AM
The 308-6578 Block does not have an orifice in either pressure sensing port. The 266-0136 Pressure Sensor (diff) does not use an orifice either. Your comment about the process of slowing the air flow down to the pressure sensor ports make some sense. I will pass this on to the engineer staff. Thanks.
03-02-2018 12:30 PM
First off for all of the techs that are having issues with ULBs swing when first started I have found a trick to calm it down. Pull the tubing line from the intake (engine side of throttle plate) to the DP sensor lose and bleed the air out. Then slowly tight tubing back up.
As for my issue we have istalled a ball valve in this same line to try and tune engine to handle load and not swing while in Nox feedback. We have found that if we restrict flow using the ball valve then unit runs and controlls like it is supposed to. Looking at the base for the DP sensor we have noticed the sensing line that runs to the aftercooler has an orifice installed. The line that runs to engine side of throttle plate (where we have the ball vale installed) does not have an orifice. I am trying to verified if this block (part number 308-6578) is supposed to have orifices in both ports or just the 1. We have not found another ULB at this time to compare with yet.
Thanks in advance,