Rough Idle p0278
 

All of sudden my truck (2003 6.0 105k) has developed a rough/lope idle and brief white smoke on startup.

I'm using Forscan and if it can't go far enough I'll get the Autoenginuity. Codes are p0278-60 and p0401-60. I'm trying to see if Forscan can do an individual injector test (so far it doesn't do anything) and if the buzz test goes more than 4 injectors (the 4 it does do passes). I cleared the codes and just at idle the p0278 returned.

I'm looking for the next steps to diagnose this issue. Is checking the harness or bubble test the next step? I'm guessing for the p0401 I should clean the EGR valve. Thanks for the help!


TL;DR (more info)
A few days ago when I came to a stop after the normal freeway drive to work it started a lope/rough idle. It cleared up when the truck was restarted or driving around town and didn't appear on the trip home. (It has done this before randomly and rarely after injector replacement at 85k). The next day it did it both on the trip to work and the trip coming home. Revving the engine up and down sometimes helps, but even at it's best you can feel a stumble. The truck sees no town/stop-go driving. Our city driving is 40+ mph and most of my driving is on the freeway at 65+. I don't idle it excessively and perform at least 1 WOT acceleration to freeway speeds per week.

I've drained the water separator 2x (fuel filters changed every 10k) and filled with fresh diesel resulting in no change. Blue spring has been installed since 75k, fuel pressure gauge shows 62 and boost is normal. Deltas, ICP, IPR, Volts and FICM check out per the scangauge. Always add a mix of diesel kleen and 2 cycle oil on fillup. Using 15w-40 Delo dino oil and change at 5,000 miles (an oil change was performed a month ago). Outside temps have been 60s-80s.

Truck has 107,000 miles and has sat (with a battery tender) the past 18 months, but driven at least twice a month each month for 60-200 miles at a time not including longer vacation trips. It's now my dd again; back at 85000 miles it was also my dd and had similar symptoms only worse. It was under extended warranty and the dealer replaced #7 injector, EGR valve and MAF sensor. The EGR and MAF threw codes, but the injector code wasn't listed in the write-up.

Ever tried any stiction additives in the oil?

Might also try a good 5W40 synthetic oil as well.

Do you monitor your FICM voltages?

I would also add the jury is still out as to the benefits of two cycle oil, in fact I think the majority of 6.0 guys, at least from what I have read, will say it does more harm than good.

As Mark mentioned, you can try something for stiction.........Archoil 9100 is a really good one, along with a good synthetic oil of the weight he suggests. I've run it in the past for a mile case of stiction, before switching to Schaeffers synthetic 5W40, at which point seemed to be good enough on it's own.

I run Opti-lube XL injector additive in the kids truck, for the fuel side of things.

Archoil may help for awhile, but you need an injector, and the only way to test for that easily is uncompensated with an IDS. Napa had a tech bulletin somewhere on how to hunt without IDS looking at fuel while pulling connectors, but I was uncomfortable with that.

No stiction additives, is there anything cheaper than archoil? EOT/ECT and FICM/VLT are always monitored via scangauge. FICM is 47.5-48 and logic matches vehicle volts, just replaced batteries last month, volts is 12.6 off to 14 while running. I've been hesitant to try synthetic because of cost vs the benefits for AZ temps. However, I'm going to try it as it can't hurt and I'm interested to see it's affects on the few cold starts we have.


Not sure if there's a new study out, but according to the Lubricity study 2 cycle wasn't the best, but was in the top 10. I use it around 1oz per gallon along with 8oz Diesel Kleen since it quiets the injectors. I can tell if I forget to add it or top off and dilute it. Thanks for the Opti-lube XL recommendation, I might try that as it will simplify the mixing and appears to cost about the same.

That's what I was thinking. The additives will only prolong the inevitable if it's the injector. When #7 was replaced there was no code and they used the IDS as mentioned. Is there a way with AE to see if other injectors are failing? I would hate to tear into it and then do it all over again.

Plenty of folks down that way run 5W40.
AZ is not the only state that gets hot :) we just don't see it as many months out of the year.
It's still similar to a 40 weight once warmed up, I'm sure you probably know that already.

That said, I know a lot of guys around here that run nothing but 15W40 year round, but then wonder why they start harder during the winter months.

You can use FORScan to disable the injectors one by one. click on my user name and find my pic albums. In there I took screen shots of how to do it. Sorry on my phone to difficult to link.