6.4 Constant regen, no codes surges and low power.

amailloux · October 13, 2013

I have a 6.4 in that is in constant regen. I have made a few recordings of the data, and made somw observations. It starts out ok, then after just a couple miles loses power and as soon as the ect is high enough it

goes into regen. I drove 45 miles and noted low power. MGP low, MAF follows MGP and there is a lag for 5 seconds or so, then a surge, and this kind of continues. All 3 pressure pids are 12.1 to 12.25 koeo. DPF shows part loaded, regen active, and the DPF pressure is in the 3-5 psi under load depending on the surge. One thing is that the EGRTP is closing, and opening somewhat in line with the surge and mgp and maf drop. Dist regen complete is 47 miles. Is requesting all the time. I checked the ebp tube and sensor, and maf and then swapped

them from another truck even though they looked good in scan data. I removed the downpipe and there is no

oil. Low pressure checks ok from the front and rear. So I disconnected the pipe in front of the converter. I

went for a drive and had good power. No surge, and of course no dpf request. I removed the converter and

checked it out, and it was not melted, nor broken. It was heavily sooted up??? I blew out the converter and

washed it and put it back on. Ran great for 12 miles or so, then same thing, went to regen and had same symptoms. DPF pressure still under 5 psi full load, or as full as I could get it. Still only shows part restricted as the load. Relative compression is ok, crankcase is not overfull. So I go out again and when it is in regen, egt 1 is about 750 to 800 degrees, and egt 2 never hits 1000 degrees. also egt 3 is higher than egt2 by 100 or so degrees. So I am thinking the cat is not able to oxidize the added fuel, as egt 2 I believe is usually in the 1.1 K

range, and the fuel is being oxidized partially inside the dpf. I have no soot on the tailpipe, and when I had the

converter disconnected I did not note any black smoke under full load. This thing set no codes. passes koer. I have been losing sleep over this one, and need some help.

Thanks alot

amailloux · October 13, 2013

I actually swapped a cat from one of their other trucks in for front end work, same thing. performed a manual regen, but when I was checking on the progress, accidentally hit brake pedal and regen ended. Now it does not regen immediately, but is only building 15 lbs Mgp. Really odd thing is if I shut odd the truck for 10 seconds, the first acceleration is good with over 35 psi, then it slowly begins to lose power again. Checked cac, not restricted. Need to get some fuel, and then get the dist. Regen Complete to clear and retest. Now I am thinking possibly a hp turbo concern, but after a key cycle it has good boost right off. Software is. Current, and vin is correct.

Aaron · October 13, 2013

KOER in park, what does your EBP read if you smash the throttle wide open?

Brad Clayton · October 13, 2013

Had one doing the same thing and after I did a manual regen, I cleared the DPF tables and all was good.

Keith Browning · October 14, 2013

Ain't wheez only sposta clear the DPF table ifs wee tries a new one In the truk?

amailloux · October 14, 2013

EBP_A was 33 psi and desired was 21 PSI. This was matted. I did see the egr was opening slightly. I commanded it to 0 but the vehicle would not let run wot with the egr at 0%. Our baro was 12.1 this morning. DPF pressure was 3.5 wot. I am going to get fuel and then perform a complete manual regen, and then check the dpf pressure at wot and idle, then drive to see how long it takes to complete a regen, and how it performs. note: when I disconnected the downpipe from the converter the dpf state stayed clean, or system leak, and had normal power. Then I am thinking of getting the ok to pull injectors and do the inverted test and check for excessive return or dripping. Also my egr valve closed is 1.15 volts, which is in spec, and it responds normally during the egr test. Is it possible that it is leaking. My maf numbers aren't extremely low, so it would have to be just slightly leaking. Is it a spring return, or is the position sensor directly connected to the valve?

Bruce Amacker · October 15, 2013

Also my EGR valve closed is 1.15 volts, which is in spec, and it responds normally during the egr test. Is it possible that it is leaking? Is it a spring return, or is the position sensor directly connected to the valve?

It's a stepper motor, appears to be powered both ways and not a spring return. Click the photo for a video.

Under Programmable Parameters, there's a "Reset EGR Valve Position Sensor Offset" that I assume is for setting the closed valve voltage. Does anyone know more about this?

:grin:

amailloux · October 15, 2013

Not the easiest thing to pull out and check. I have had spring return valves cause dpf plugging on other makes with no dtc's, but maf is slightly lower and they list an e/q ratio pid to check.

Keith Browning · October 15, 2013

Under Programmable Parameters, there's a "Reset EGR Valve Posision Sensor Offset" that I assume is for setting the closed valve voltage. Does anyone know more about this?

The words you used are different than what is in the PCED as I assume you mean "Clear EGR Valve Adaptive Tables" using IDS? If so then you are correct in that the purpose is to remove and relearn the EGR voltages which will quite likely be different if a new valve is installed. But knowing that you are not someone who just pulls technical stuff out of thin air... I haven't performed this in a while. Is there something new in the service functions menu on IDS?

Bruce Amacker · October 16, 2013

I took this capture several years ago on a 6.4, it's possible/likely that this selection no longer exists:

:grin:

lmorris · October 16, 2013

It's gone. I have never actually seen that option before.

Aaron · October 17, 2013

I remember seeing it.

I have an old ass version of IDS on my other laptop, if I can pull the ripcord hard enough and get that thing fired up, I will see if it's still on there.

Matt Saunoras · October 17, 2013

I have IDS v40 on my one laptop. It doesn't even know a 6.4 exists

Bruce Amacker · October 17, 2013

The file (when I took the captures) is dated 7/10/2007. :haha2:

amailloux · October 18, 2013

Well, finally got back to this one. Pulled right bank injectors and checked for leakage. All 4 injectors leak from the return ports when cranking.

I am seeing drips come off. So, I know it needs injectors. I checked the history and see it has had a pump for p0088 earlier in life. Sooo, do you think the injectors are the cause of the regen issue?

amailloux · November 5, 2013

This one still hasn't left. I replaced leaky injectors and drove 180 miles. at 180 miles, a regen started, and the symptoms returned. I

ran a manual regen and the dpf cleaned. Although right after the regen, I popped the oil cap and there was some heavy smoking. I

immediately ran the relative compression and #8 was 5% dowm. I then pulled in and the truck cooled off and relative compression was

zeros across the board, and 1 time, #2 was 1% low. I pulled glow plugs and had 350 to 375 on other cylinders with #8 at 325. I am having a hard time with how well the truck runs until a regen is requested. I understand #8 is low, and with the extra fuel, I think it is washing out and losing compression, but my manual compression test is only 25 low. Any thoughts.

Brad Clayton · November 5, 2013

I popped the oil cap and there was some heavy smoking.

I would do a crankcase pressure test next. If she's above spec, I would suspect one or more bent rods (#8) allowing oil to be pushed into the exhaust and miffing up the DPF.

amailloux · November 5, 2013

I ran until hot again, and found #8 %5 low relative, and under 300 psi manual, 6 was 350 psi. I guess I need to tear it down. The crankcase pressure tester is at our other store at the moment, but I highly suspect it will fail hot at 2500. Time to pull the head. I think bent rod and scuffed cylinder wall, or severe erosion as the truck has idled most of its life and most likely has had overfull crankcase more than 1 time.

Keith Browning · November 6, 2013

Yes you need to get into this one. We need to remember that you cannot go by how a 6.4L runs as it can compensate until thdamsge gets bad enough... And now you have seen how relative compression tests on these engines can mess with you.

amailloux · November 8, 2013

Well, they are going to pull the truck out of srervice so I am not tearing it down. They just brought in another truck, almost identical. Vin is 2 numbers newer. It has 8600 hours, 4000 mile old particulate filter, and in reduced power. I put rocker arms on 8000 miles ago. Had 1 eject, and there were no tips on any of them. I asked the driver how the truck is used and got "it sits on location for 2 to 3 days and idles to run electrical stuff". It looks like 8500 hours is all they are going to get out of these engines. Averaged 13.x mph. I did a manual regen and the filter cleaned, but there was some bad noise from the lower end.

ktmlew · November 12, 2013

Well, they are going to pull the truck out of srervice so I am not tearing it down. They just brought in another truck, almost identical. Vin is 2 numbers newer. It has 8600 hours, 4000 mile old particulate filter, and in reduced power. I put rocker arms on 8000 miles ago. Had 1 eject, and there were no tips on any of them. I asked the driver how the truck is used and got "it sits on location for 2 to 3 days and idles to run electrical stuff". It looks like 8500 hours is all they are going to get out of these engines. Averaged 13.x mph. I did a manual regen and the filter cleaned, but there was some bad noise from the lower end.

You would think a generator would be cheaper than a 50K truck...

amailloux · November 13, 2013

I talked to another driver requesting high idle on his 6.7. I guess I will find out how many idle hours they can take also. I love the idle hour reading on the 6.7. Had a 550 come in for it's first service with 5015 miles, 520 hours and 315 idle hours. Nao matter how hard I try, the drivers can't get them in every 200 hours. The fleet wants it done at 5000 miles or 200 hours.