17How to Determine if the DPF or DOC is Viable Tech Tip TECH Tips CATALOG NUMBER 17 www.midwestwheel.com Order NLINE ™ www.midwestwheel.com Order NLINE ™ How to Determine if the DPF or DOC is Viable 1) Visual Inspection: DPF Inlet (the Dirty & Engine Side) ▪ The inlet will look blackened across the total face of the filter, which is normal (See 1st image) ▪ However, there shouldn’t be any excessive soot such to the degree of DPF face plugging or heavy accumulation of soot (See 2nd and 3rd image). This would signal likely upstream engine and/or DOC issues that require investigation. The inlet should be free of cracks/damage. DPF Outlet (the Clean Side) ▪ An u ndamaged DPF should look almost brand new like the day it was installed and off-white to beige in color with no signs of any cracks or soot by-pass (see figure 1). ▪ Evid ence of significant soot by-pass with the soot-staining on the outlet side is confirmation that the DPF is breached/cracked and needs to be replaced and should not be sent out for cleaning. » Figure 2 shows significant soot by-pass = failed DPF » Figure 3 shows blown cells (small back dot on the outlet) and still viable provided less than 20 cells, however, multiple cells in one area (size > dime/nickel) = failed DPF » Figure 4 and 5 show signs of staining by coolant or oil which signifies upstream issues and = failed DPF when combined with black soot staining » Figure 6 shows cross-sectional cracks evident by soot staining around the outer diameter » Figure 7 shows DPF substrate melting and uncontrolled regeneration with likely upstream engine and/or DOC issues and = failed DPF 2) Pin-Gauge Testing A pin-gauge test is an inexpensive and useful tool to help determine and measure how dirty the DPF is via the inlet side. By inspecting the outlet side, you can get feel for how an unobstructed channel should track with the pin- gauge and possibly confirm any internal DPF flaw and/or cracks if the rod path is obstructed via the outlet side. Pin-gauge specs: Approx. 0.032 to 0.034” diameter stainless steel wire/rod x ~24” long. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Made with FlippingBook RkJQdWJsaXNoZXIy MTEyNjY3NA== 17How to Determine if the DPF or DOC is Viable Tech Tip MIDWESTWHEEL.COM IOWA MISSOURI DES MOINES 1436 E. Ovid Ave. office 515.265.1491 fax 515.265.4120 parts fax 800.314.4329 parts 800.888.0248 CEDAR RAPIDS 200 50th Ave. S.W. main 319.365.4453 fax 319.365.6327 parts fax 877.706.6085 parts 800.332.5435 DAVENPORT 8502 Northwest Blvd. main 563.322.2671 fax 563.322.5940 parts 800.553.1886 SIOUX CITY 1819 4th St. main 712.252.7969 fax 712.252.6149 parts 800.943.3534 CLEAR LAKE 840 Hwy. 18 W. main 641.357.7101 fax 641.357.8190 parts fax 800.548.9674 parts 800.397.5630 TRUCK PARTS SUPER STORE TM KANSAS CITY 5801 E. Front St. main 816.471.1552 fax 816.471.0813 parts 800.821.7402 JOPLIN 2424 Stephens Blvd. main 417.717.6022 fax 417.782.7126 parts 866.318.9111 October 10, 2019 (17How to Determine if the DPF or DOC is Viable Tech Tip) Outlet Side: ▪ Determine the and measure the overall length of the DPF substrate. ▪ The thin wire rod should pass freely down the entire length of each outlet channel of the DPF less approximately 0.25”. Blocking in the path may signal an internal flaw/crack & possible DPF failure. ▪ Approximately a dozen channels can be spot-checked and if flaws are detected then additional adjoining channels can be checked to confirm no single-cell isolation. ▪ This inspection should be documented before cleaning and after to ensure the DPF was not damage during the transportation and/or DPF cleaning process. Inlet Side: ▪ Similar to outlet side but resistance can be used to measure and document the level of impacted ash and soot. ▪ For example: 12” long filter and rod that only travels ~ 6-8” in different areas/grids can be documented before cleaning to measure how “dirty” the DPF is prior to being cleaned. ▪ Re-measure after DPF cleaning and the rod should be expected to travel full length of the DPF or very close to it demonstrating that the pre-measured impacted ash and soot was successfully cleaned and removed. 3) High-Lumen Light Test with a Bright Flashlight or Work-light Finally, a light test with a bright flashlight or work light can be used to confirm internal cracks and/or DPF breaches that may not be evident on the surface. Inlet/Outlet Sides: ▪ Shine the light through one end while observing through the opposite end and moving your eyes from side-to- side across the diameter of the DPF face. ▪ No light should be visible when directing a bright source at the opposite face of the filter. If any light passes through the DPF there is an internal flaw or crack. ▪ Testing can be conducted prior to DPF cleaning and afterwards to confirm the DPF was not damaged by the DPF cleaning process or handling. DOC Viability: The DOC is a commonly misunderstood, misdiagnosed and overlooked component within the exhaust after treatment system. However, it is an integral component and is the backbone for supporting passive and active regeneration. If a deactivated/poisoned DOC is re-installed, then the DPF will not regenerate and you will be back where you started without solving the root-cause of the problem. Evaluate the following: ▪ Force DOC regen after re-installation to check sufficient temperature rise across temp 1 and 2 sensors. ▪ Service history of failed turbos, EGR valves/cooler, or bad in-cylinder injectors (possibly poisoned the DOC). ▪ Moreover, as a catalyst gets poisoned, the passive efficiency is compromised so increased frequency and duration of active regenerations is a warning sign of a likely poisoned/weak DOC that should be considered for replacement. Especially recurrence shortly after a DOC & DOC PM maintenance interval. Made with FlippingBook RkJQdWJsaXNoZXIy MTEyNjY3NA==