View Single Post
  #4  
Old Fri, May 20th, 2022, 03:17 PM
bighorn466e bighorn466e is offline
Whopper
 
Join Date: Jun 2021
Posts: 6
bighorn466e is on a distinguished road
Default Progress Update

I just finished another series of road tests with the IAT sensor in its original place, an oil cooler that was disassembled and verified to be clean and a new viscous fan clutch adjusted two notches counterclockwise from the factory setting shown in the attached picture.

No major changes were observed, when the engine is cold at full load I see ~18psi at 2100 rpm and then as things heat up I drop down to 15ish psi. The strange part to me that makes me feel that this has to be an issue with the computer side of things is that hot or cold I am back to the spec 20lbs of boost by 2400 rpm.

Next steps for me are installing a pyrometer and fuel pressure sensor. My thought is that if I can observe lower egt's corresponding with lower boost at the same fuel pressure than I'd feel fairly confident saying something is causing fuel to be pulled as the engine warms up.

Other Notes:
The old fan clutch certainly wasn't helping things. The new clutch is a bit quieter at idle and coolant temps don't exceed 190. Before installing the new clutch I adjusted the bimetallic spring 2 notches counterclockwise to keep underhood and coolant temps a bit lower while working everything out. The maximum IAT recorded was 137 compared to a max of 105 with the sensor draped in the airbox.

While disassembling the oil cooler I did note that the oil cooler temperature valve had a 220 and 240 stamped in it. Thinking these were the open/close temps of the oil cooler I tested the valve in boiling water and then in the oven. The valve didn't open at 212 submerged, started opening around 220 dry (13mm) and was fully open (26mm) by 240 dry. While this didn't wind up being helpful for me it may be good to keep in mind that there is likely negligible cooling happening in the oil cooler until 220 EOT.

Truck has had oil, oil filter, fuel separator, and fuel filter replaced as part of the troubleshooting process.

The engine was replaced with a navistar renewed unit while it was still a customs and border patrol vehicle. I'm fairly confident the engine has <3k miles on it because the oil thermostat was stamped 3/17, carfax has towing and service records on 1/19 at 16k odo and the truck was sold 11/20 with 18k on the odo. The turbo and longblock seem to be new while the computer seems to be original. One of the considerations I have had is whether there could be a mismatch between the newer engine and the original ecu.
Attached Images
File Type: png oil_cooler_cleaned.png (484.1 KB, 4 views)
File Type: jpg valve_closed.jpg (263.3 KB, 7 views)
File Type: jpg valve_open.jpg (226.7 KB, 7 views)
File Type: png dt466_cooler_flow.png (100.0 KB, 7 views)
File Type: png dt466_lube_flow.png (156.2 KB, 5 views)
File Type: jpg factory_setting.jpg (107.2 KB, 5 views)

Last edited by bighorn466e; Fri, May 20th, 2022 at 03:18 PM. Reason: added fan clutch picture
Reply With Quote