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6.7 Frequent Regen

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So I have this 2011 F-450 in the shop. 76175 miles and 1600 hours. They average around 48 MPH according to my math. Customer complains of low power and poor fuel mileage. Now I've driven enough 450-550 trucks to know they suck on power compared to pickups, but this company actually owns several of these trucks and they are all upfitted the same. Both are F-450s, crew cab, 4WD, and fitted with a large cab over box on the back.. So they have something to compare it to. So I road test it this moring and it seems to have normal power, other than it goes into regen as soon as I leave. I check for DTC's; none stored in memory and no KOEO or KOER codes set either. Checking OASIS found another dealer in Texas put in a long block, #5 injector, HPFP, and turbo due to an overfueling injector that melted a piston. But that has been a year and 20k miles ago. So looking through data logger I see the DPF_REGEN_AVGD reads 28 miles, and DIST_REGEN_C is 10.87 miles. DPF_LOAD_PCT is 48%, and DPF_SOOT_INF is 1.849  Power balance is smooth, relatvie compression is good. Engine runs smooth, CYL_BAL pids 6 cylinders read .00gr, while #6 reads .02gr and #7 -.01gr. INJ_Q_TOT numbers are all around .13gr at hot idle. Oil is not overfull, and all other fluids are good. I can't get it to do a manual regen, IDS keeps stating Regen timeout. I don't see a reason why it's going into regen so often. Any ideas? Am I overlooking something? I've yet to contact hotline, figured I would see if any of y'all might have seen this issue yet.  

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Did the other dealer replace the exhaust system since the DPF was probably contaminated from the burned up piston? Maybe it's plugged up now.

 

From what I can tell no. Im thinking that the overfueling injector has caused this DPF to become plugged, but I'm not sure how to prove it since it has been 20k miles since the long block was installed. I was incorrect as the oil level is overfull.

 

Here is my conversation with hotline this morning...

 

--------------------------------------------------------------------------------

Request Form Details:

Description of Vehicle Concern:Customer states no power and poor fuel mileage..

Diagnostics Performed:Verified concern; found engine is low on power. Visual inspection found oil overfull on dipstick, but all other fluids ok. Performing KOEO and KOER test found no DTC's, and there is no CMDTC's stored. Road test in data logger found no obvious issues, but did note that DPF_REGEN_AVGD reads 27.96 miles. Engine hours are 1603, and my math puts the MPH average around 47 MPH. INJ_Q_TOT for all cylinders are around .13grms, and CYL_BAL for cylinders 1-5&8 @ .00grm, while cylinder #6 @.02gr and #7 @-.01grm. Attempted to perform a dymanic manual regen; at beginning of regen, DPF load % was 46%. After regen, this number droped to 40%, but after driving for 10 miles DPF load % increased to 70% before returning to shop. Fuel sample taken from DFCM found fuel is clean and sufficent. DPF pressure voltage is around .45 volts at idle, and DPF pressure is around 4-5PSI under a heavy WOT accleration, EBP is around 80PSI, with MAP showing 40PSI. VGT remains around 40-45% at this time.

Parts Replaced:NONE.

Question: Body Conversion:Answer: DELIVERY BODY

Technician's Question:At this time I am unable to determine reason for such frequent regen at 27 miles between regens. Since I have no DTC's to diagnois by and I am unable to locate a test in the symtpom chart for excessive regen, is there a pinpoint test you would recommend to use?

Additional Comments

Comment From: Ford Comment Date: 5/12/2014 12:49:46 PMChad,It is recommended to record the Engine Idle Hours as this is a more accurate method of determining the vehicle idle time. Ensure that the Engine Idle Hours is not a large percentage of the Engine Hours.With the frequent Regeneration of the DPF occurring, it is recommended to perform a check of the intake sensors for any bias that may be present.It is recommended to perform a KOEO check of the MAF, MAP, EBP, BARO, and the DPF Pressure sensor. The MAP and BARO should remain within 0.73 PSI of each other and the EBP and BARO should be within 1.09 PSI. The DPF should read 0 PSI and be near 0.45 volts at KOEO (as you have indicated earlier). The MAF will need to be compared to another 6.7L quipped vehicle and these two KOEO readings should be within 300 Hz of each other.It is recommended to remove the MAP and the EBP and inspect them both for any carbon blockage within the sensor port. If the sensor is found to be blocked with carbon, replace it. A check of the ports into the engine can be done to clear any blockage. If necessary, a wire or tool can be run into the ports to clear any blockage. Remove the MAF and ensure that it is not contaminated with oil, dirt, or debris. Ensure that there are no aftermarket items in the intake such as oil/foam filters, intake boxes, or piping.With the concerns in the Regeneration Cycle, it is recommended to perform a pressurized smoke test of the intake and the exhaust to ensure that there are no leaks present in these system. This pressure test may be performed as per Pinpoint Test KA3 from the online PC/ED Section 5. When performing the pressure test, ensure that BOTH the Intake and Exhaust system are capped at their ends as this will prevent any cross flow through the internal system within the engine. Be sure to use a separate 20 PSI regulated air source other than the smoke generator. Most smoke machines only produce 2 PSI of pressure which is not enough to properly test a turbocharged system.Note that Regeneration Cycle will not begin on the 6.7L engine until the DPF Load reads over 100%. This load reading is inferred and may reach levels well over 100%. With the pressures reaching only 4-5 PSI during the WOT accelerations, this appears to be a normal condition.Further testing of the Frequent Regeneration may be performed from Pinpoint Test RB from the online PC/ED Section 5 following the P2459 DTC. The Symptom Chart 15 from the Online PC/ED Section 3 should be followed when there is no DTCs present as this will further test the other systems in the vehicle that may cause frequent Regeneration.

 

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I'm a bit surprised at his comment on idle hours. A 47 avg mph truck doesn't idle.

The only vehicles I ever see that kind of avg mph on are rural expressway use with no idling.

I get 39 avg mph on a vehicle I commute in from rural to edge of the city location. Few traffic lights or stops and very little slow speed driving on the commute trips.

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I'm a bit surprised at his comment on idle hours. A 47 avg mph truck doesn't idle.

The only vehicles I ever see that kind of avg mph on are rural expressway use with no idling.

I get 39 avg mph on a vehicle I commute in from rural to edge of the city location. Few traffic lights or stops and very little slow speed driving on the commute trips.

Yea I was too. Engine idle hours are 232. I've got a few trucks I've got to get done before I can really focus on this one, I'll do as he asks and see where that takes me first.

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  • 2 months later...

Not really. I tried several times to do a manual regen in the parking lot, but it would never complete so I did one driving. Afterwards I reset the DPF adaptive in the PCM and my boss drove it 40+ miles. Truck was averaging 8.4 mpg when it came in, he got it up to 11. These trucks go across country carrying stuff for missile testing, and they have several others to compare it too. This truck is running around 6k lbs over the GVWR rating( I found a copy from a weigh station). We also changed oil and fuel filters and sent it on its way. Haven't seen that truck back yet, and they didn't say anything when they dropped off their 6.0 truck a few weeks ago.  

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