6.4 Aftertreatment Diagnostics

[Bruce Amacker]

This is a list of screen caps I use in class to continue a private conversation between Keith and I. Any comments you guys have are welcome. What PIDS do you use when diaging aftertreatment?  What opinions do you have on my captures? THANKS!  

[Matt Saunoras]

Don't forget about the importance of MAF and it's use in DPF load calculations.  I learned the hard way the DPF pressure sensor isn't the only input. 

[Keith Browning]

One of the things I noted when talking to Bruce is that I really don't see too many DPF concerns but when I do it is usually related to base engine failures that cause excessive fueling in multiple cylinders or problems related to vehicle usage. I am surprised that we haven't had too many discussions related to this. Am I not the only one seeing few issues with regens? It makes it hard when you don't see these types of PID recordings often so I am glad Bruce posted this.

[amailloux]

I have a rash of 08 trucks right now, 1 of which I have in my bay right now. Most have high Idle controllers and they run for no reason on site all day. With cold weather coming we see them a lot. Also many are at about 120 k miles. I have 3 replacements so far this month. The one in my bay looks to have a new dpf about 200 miles ago. Runs .2 psi at idle, 2.5 at high idle and surges like crazy going down the road. Wot hard accel I can get over 6 psi. Constant regen, hard to keep over 60 mph. Also no codes. Stft for #1 is 13 , and a few others are -5. No oil I downpipe from turbos. I am interested in the maf calculation for soot loading. I see very few p0101 codes, and don't have a good baseline on maf yet. I have tried the maf test in the wsm and each time I am right at the top of the specs, sometimes just a hair over.

[Brad Clayton]

The dealer I came from was a 126 report rock hound. Getting anything done was next to impossible. I replaced some engines that were chugging a quart of oil every minute out the tailpipe and still couldn't get management to sign off on replacing a DPF.

 

As for around here, emissions are pretty relaxed on diesels, and there aren't to many cops that want to crawl around under these trucks looking for tampering. Sooooo any assumed DPF failures usually end up with the ol, let me get back to you. Mean while they are on every internet site looking for delete setups.

 

I guess I am trying to say I could use a refresher course on DPF diagnostics myself.

 

I shudder to think what will happen in the future when states crack down on inspections and the cost of failed after treatment systems are in the multiple thousands of dollars to replace.

 

Nice screenshots Bruce.

 

[2006]

I see a lot of trucks that are used in city driving and short trips. They always have overfilled crankcases with overdue regens.

 

I find the biggest issue is that the customer really does not know when it is in regen. The  message center  shows "Cleaning Exhaust Filter" for a few seconds and unless the driver is looking at the cluster all the time, they are going to miss it. With overdue regens, the  "Drive to Clean" message comes on, and stays on, but then the crankcase is already over full. 

 

There should have been a idiot light on the dashboard when its in regen, so the customer knows not to turn the truck off and to take it for a highway drive.

[Brad Clayton]

Sorry but I aint ridin around the country side for no reason other that to clean my exhaust filter. If it cant clean itself and at the same time kill my fuel mileage whilst I am purposely driving then the engineers should reconsider the whole thing.

[mchan68]

Sorry but I aint ridin around the country side for no reason other that to clean my exhaust filter. If it cant clean itself and at the same time kill my fuel mileage whilst I am purposely driving then the engineers should reconsider the whole thing.

Threads like this make me SOOOOOOOO glad I bought myself a 2007 truck at the time that I did. I had a chance to score a 2008 at that time with about the same mileage as my 2007 had, for about the same money I paid for my 2007. Thank God I said NO WAY to the 2008.

[mrbudge]

Sorry but I aint ridin around the country side for no reason other that to clean my exhaust filter. If it cant clean itself and at the same time kill my fuel mileage whilst I am purposely driving then the engineers should reconsider the whole thing.

Yes, re-engineer the whole thing. I am sorry to say that I think the effort it is taking to run an engine on diesel fuel is exceeding it's benefits.

 

In Europe, where diesels are revered, they plug the dpf's in their cars because they can't get out of the congested cities and run them hot enough to do a regen, even with their superior quality fuel. I don't think a DPF delete would be an option for them.

[Brad Clayton]

Damn, I was hopin I would get a rise outa somebody on that one.

[Steve Mutter]

I have one I just did a manual regen on and the dist_regen_c pid did not re set to 0 after.  The pid should re set right?

[Steve Mutter]

I forgot to add that it re set the other pid dist_regen_req

[Bruce Amacker]

You'll notice I had the exact same thing happen in my captures above (12th one down) ....

 

 

[Steve Mutter]

I called the hotline and asked them why after I performed a manual regen why the pid would not re set and they told me it was because it did not complete.  I don't get it because after the manual regen was done it told me that regen had been successfully completed. Maybe its a software problem. 

[lmorris]

The last 2 manual regens I have performed did not reset that either. One, however, I had to drive for another 15 minutes to get the "Drive to clean exhaust" message to go out after the manual regen said it was completed. I rechecked the pid and it had reset after the drive.

[Steve Mutter]

The truck I was working on got a new dpf in the end,so when I went to re set the dpf table thats when I the noted the dist_regen_c finally re set.

[fergy12]

Wow am I ever glad we are on this topic, I have 2 2008 6.4L that have me scratching my head and loosing money the last few weeks.  First is a 2008 ambulance, came in wrench light on, check engine light on.  Codes P2463, P246C, and a DPF pressure sensor circuit range performance (cant remember which one)  Attempted manual regen 3 times, would not regen, attempted roadtest regen, went into regen but kicked out of regen coming up with codes P2463 and P246C.  Replaced the DPF due to being clogged, reset DPF tables cleaned out Map sensor, inspected EBP tube and sensor no restrictions, and replaced the MAF due to not reading 0G/s at KOEO.  Roadtested this vehicle it worked fine, DPF pressure at idle .06-.15, load status indicating clean the whole roadtest.  Get back to dealer shut vehicle off, turn key on to do a KOEO test all pass.  Turn key off then start vehicle to do a KOER test begin test and notice instrument panel says drive to clean exhaust.  Cancel KOER test, go into datalogger, DPF load state clean,distance since last regen requested 27Km... what gives?  IC says drive to clean but PCM according to IDS did not initiate request.  KOEO codes now P2463.  Cleared code, codes returned with freeze frame data 1 second after startup, 700RPM.  So back into datalogger watching DPF pressures and voltages at idle .51V, Pressure .15psi with no erratic readings, 0psi KOEO. Crankcase pressure at 10"H20, but doubting that's an issue 1 second after startup.  Its just baffling because everything that should set that code has been replaced.

 

Second one has been awhile since I looked at, it was frequent regen, every 100-150km highway driving.  No codes, enhanced injector balances all looked okay, New MAF, MAP, EBP no change.  Would complete regen just fine.  Only thing I have really found with that one is Crankcase pressure is high at 12-14"H20.  Hotline thinks its not a 3/4 full DPF so been driving this thing for weeks trying to figure it out.

 

Thanks for posting the above readings, it gives me a little something to reference to as normal readings.  Have had a few DPF issues prior, injector issues, oil issues but these two are kicking my a**.  Any ideas or experiences with related symptoms and fixes are much appreciated!

[amailloux]

Get it smoking hot, like right after a manual regen and do a cranking compression test, then a manual based on the results. Had 1 similar and it had regen issues due to low compression during a regen, and the added fuel causing the problem to manifest itself.

[fergy12]

okay that's something i'll look into. on the frequent regen, With the high crankcase pressure readings i was getting (12-14"H20, suspecting turbo, with CAC tube discononnected crankcase pressure drops) Now opinions or better yet personal experiences, high crankcase pressure causing excessive regen?  (skewed maf readings, oil mist entering intake system due to excessive blowby)

 

I will be doing a manual compression on this truck either way.  Lately the old compression tester and crankcase pressure tester have been getting a workout, and usually ends badly on the 6.4.

 

I apologize I kind of took this post off of the original question, but I use pretty much all the same pids mentioned above, never knew what the DPF time pids were for.  Your power balance diagram looks somewhat similar to one I just have all tore apart in my bay.  Ran fine, vehicle had a miss cold, customer never noticed but threw code for cylinder #6 misfire. Now short term fuel trims hot all within +-10.  cold cylinder #6 11-15.  Hot with fuel rail pressure cranked up to 15,000psi, I got a small drop like you see from cylinder 2, and 4, and a slightly larger drop from cylinder #6.  Cylinder #5 was overcontributing similar to what cylinder #3 is doing in your diagram.  So I had #5 Overcontributing and #6 Undercontributing similar to your diagram, just different cylinders.  Relative compression passed, Manual compression #6 320-330 psi, 2,4,8- 340psi, 1,3,5,7-360PSi.  All in all pistons touched valves, bent rods slightly, scored cylinder wall slightly.  DPF delete so can't tell ya if it had frequent regen.

[tuff57]

can we sticky this?

had a truck tonight 945 miles since last regen completed came in with overfilled cranked case code (was about 3 gallons over full). I don't know if it was mentioned here, but the PCM will command a constant regen until one is completed after the truck has went greater than 667 miles. The DPF had a ton of oil residue in it, drove it to clean out the dpf. Manual regened it, didn't reset on IDS. Looked furthur into the situation and the truck would blow black smoke while goosing it, condemned DPF failure.

[Bruce Amacker]

OK, let's talk about this again.  I am putting together a "Top Ten List" for why 6.4s regen too frequently. Here's what I have:

 

1.   Driver Abuse- Not allowing a regen to complete once started.  80-90% of the time when there’s a regen complaint all you have to do is run 1-2 stationary regens with IDS (and charge 1-2 hours for it!)

2.   Crankcase extremely overfull (more than 2-3 qts)

3.    Too much PTO time

4.    Very low MPH average (under 15)

5.    MAF problem

6.    Injector problem (Check STFT PIDS)

7.    Engine oil smoking/turbo/mechanical issue with the engine

8.   Compression is low  and the fuel will not combust properly in the cylinder

9.   Low boost- leaking CAC or related issue

 

What do you think? Comments wanted!

 

Thanks!

 

[BigWalt]

After reading Bruce's post #21.

 

#8....Compression is low and the fuel will not combust properly.

 

Will you have good manual compression reading on one cylinder but fuel can be dumping into crankcase due to broken skirt on one side of piston? 

[Bruce Amacker]

I don't have any experience with 6.4s and broken piston skirts, but I have seen them on other engines. Sometimes there's no complaint at all, compression is good, and you stumble on it accidentally doing an LOF or oil pan. Sometimes you'll hear a noise, click, or light knock.

 

Yes, you can have good compression on a cylinder with a broken skirt.  I have not seen fuel dumping from a piston skirt.  Have you seen this, and can you elaborate?

 

Thanks!

 

[BigWalt]

Bruce,

Yes,  #2 cylinder on 6.4 diesel.Came in for rough idle [ not misfiring], found overfilled oil level. drained oil.Put dye in fuel system, trace to HPFP.Replaced HPFP, re-run test, all is good except for high fuel trim on cyl #2 and oil level climbing up. Could not figure it out, numerous contact with tech line, do this test, do that test...blah, blah

Did manual cranking compression dozen times, got 410 psi on all cylinder. Ford Engineermade me to removed oil pan, found piston skirt on bottom of oil pan. Got short block installed, problem solved!I was told when engine is running, the force of combustion l cause piston to "rocked" inside cylinder bore this can cause some fuel to leak past the rings............so they say.......Today I got 6.7 diesel, did exact same thing, no misfiring,  fuel MASS on cyl 4 is way off, compression is 450 psi, oil level is rising, new injector did not fixed it...tomorrow I will dropped oil pan and see what's up.

[wewille]

I would agree with your top ten list. Have you guys been seeing anything new over the past year?