Developed specifically for Professional Medium/Heavy Duty Truck Technicians, this training series covers topics in all of the key skill areas. Choose from interactive training in Brakes, Electricity and Elextronics, Preventive Maintenance, Suspension and Steering, Heating, Ventilation, and Air Conditioning, and Drive Train.
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Prepare for your ASE Exams Online Medium/Heavy Duty Truck Series (T1 - T8) Technician Test Preparation (TTP) - Medium/Heavy Truck Series is the ideal way to gain the expertise required to pass the T1 through T8 ASE exams.
I just had fault codes for high DPF outlet temp and unusual doser valve pressure. I monitored the temp during regen to 1077deg and the doser valve static was at 7lbs, and between 17.5 to 24.5 during regen. what is the spec for the fuel pressure the doser valve. the regen was sucessful. what else should I look for to log these codes thx.
hey popskull... do you have the codes so you can post them. I will post some Detroit regen information here in the next couple of days. There is a code that does come up and you are suppose to watch 2 pressures in the data monitor. If there is less that 35 psi differance you are to replace the fuel shut off valve. I will post details later.
Here is a code I see on 60S this code will most of the time be inactive. SPN 3556 FMI 1 When following the troubleshooting steps I make it step 7. - 2. and end up replacing the Doser Block Assembly. These step will have you watch Doser pressure and fuel compensation pressure. This somewhat applies to your question about fuel pressure but also applies to a unit that will not get up to temperature during a regen.
CHECK FOR REGEN TEMPERATURE OUT OF RANGE LOW Check as follows:
1. Visually inspect Doser Block Assembly and fuel lines for external fuel leaks. If fuel leaks found, repair as necessary. Refer to "22.214.171.124 Verify Repairs" . If no leaks found, go to step 2 . 2. Visually inspect exhaust system for leaks including ATD V-band clamps. If leaks found, repair as necessary. Refer to "126.96.36.199 Verify Repairs" . If OK, go to step 3 . 3. Disconnect DOC Outlet Temperature Sensor. See Figure "DOC Outlet Temperature Sensor" .
4. Check DOC Outlet Temperature Sensor resistance as listed in Table "ATD Temperature Sensor Resistance Chart" .
Temperature °C (°F)Resistance Ω 0 (32)202.50 25 (77)221.60 100 (212)277.90 600 (1112)619.80 850 (1562)768.81
a. If the resistance is out of specification replace DOC Outlet Temperature Sensor, refer to "3.1.2 TEMPERATURE SENSOR REMOVAL" , go to step 8 . b. If the resistance is within specification, go to step 5 .
5. Using DDDL 7.X, activate a parked regeneration. 6. Once the Fuel Cutoff Valve opens, monitor the Fuel Compensation Pressure. a. If the fuel pressure is greater than 660 kPa (95 psi), abort the regen and repair the cause of high fuel pressure (refer to your engine DDEC VI troubleshooting guide for high fuel pressure diagnostics). Once the high fuel pressure is resolved, go to step 8 . b. If Fuel Compensation Pressure is between 69 – 448 kPa (10 – 65 psi), perform a low fuel pressure test; refer to section listed in Table "Low Fuel Pressure Test References" . Make repairs as needed and go to step 8 . c. If fuel pressure is between 450 – 660 kPa (65 – 95 psi), go to step 7 . 7. Is Doser fuel line pressure within 35 kPa (5 psi) of the fuel compensation pressure? a. If yes, replace the Fuel Doser Valve and go to step 8 . b. If no, replace the Doser Block Assembly and go to step 8 . 8. Using DDDL 7.X, perform Doser Fuel Line Purge Service Routine. 9. Perform parked regeneration, refer to "5.3 Parked Regeneration" . After regeneration is complete, refer to "188.8.131.52 Verify Repairs" .
Thx... By the specs you listed I see that the fuel pressure was low. The same unit was seen just this week and the code still has not returned but I anticipate that it is teetering on the edge of failure and the information posted will save me wasted steps.
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