Need help diagnosing

[Bob]

I have a problem that seems to be random. I am leaning toward injector, but not sure.

Here are the symptoms. Below 0 weather...Truck started great, warms up great, drives fine in town...get out on the highway about 5 miles and it acts like it is trying to gel. Mind you I am running treated fuel. WOT and loosing speed cuts out and missing. I pull over and it idles fine. Get back out on the road and it does it again. I get it back to town have the filters changed and a new EGR installed. Truck runs good for about a week. Then it acts up at a stop light. Warmer weather similar symptom, but on the low end...go to take off and it bogs down, cuts out, misses, blows white smoke and then pulls out of it and clears up. Seems to idle a bit funny. It might do it at the next light and it might not. It then runs great for a couple of days. I drove to work and all was good. Stop to get fuel and when I start it up it idles rough again. Does the same thing leaving the station and the next stop light as it did before. Then no problem for a day or so. It seems to have the trouble on the low end during city driving. It is warmed up shut down then started and run again. Gryphon showing no codes.:shrug:

History: About 3 weeks ago Bill and I went through FICM and ECM/TCM roll back. It ran great for a week then all this came about. I am currently running stage 3(tow mode) on the Gryphon canned tunes, while Bill works on custom tunes. Injectors are fairly new, 20k or less and the truck has a total of 135K mostly highway and towing miles.

I am going to turn it back to stock for a few days and see how it goes. Any input would be appreciated.

[88Racing]

Left a note for Cody....

[cleatus12r]

No clue.

[Bob]

Thanks guys, Ha Ha Well started great warmed up and drove 30 miles no problems. Shut it off and let it sit for about 1/2 hour. Started, warmed up and drove 30 miles again no problems. It was -15 this morning. So I don't think it is a cold weather issue. I will keep the updates comming until we figure it out. Oh, I have not changed back to stock yet.

[eabrust]

Did you do remote FICM update, or pull it out/send in/reinstall it? If you removed/reinstalled, are the FICM connectors tight and clicked in?

And if it isn't a new FICM, perhaps check it for 48V, maybe it decided to poop out just after updating (that's how my luck typically is).

Just thinking... :hmmm: good luck

Eric

[Bob]

Good point, I did the remote programming so a connection should not be a problem, but the chance that is going out is a good chance. If there was no bad luck I would have no luck at all.

Weent out later today and it did not bog down, but acted like it had a miss, real suttle. I just dont know why it is so random.

[StripperDJ]

sounds very weird...doesnt really sound like a injector issue to me.. Have you checked you fuel pressure ????? Normally the fuel pump doesnt go in and out like that,,,they just normally take a crap on you all at once,,,but im interested in knowing what it is. Keep me posted on this... It is so hard to diagnose one of these things without actually putting hands on it, but i will do my best to help...my email is brad@phptune.com Im outta town this week and i dont have my computer with me to check those emails but if need be send me a pm and with a number i can reach you at and i will give you a ring the first chance i get...... thanks,, and god bless

[Bob]

Thanks Brad. Today it has had that slight miss both times I started it and drove it. I changed it back to stock last night so it did not seem to make a difference yet. I am curious, how much oil should or could I expect to see in my inter cooler tubes. It seem a bit excessive to me. Could this be a factor? I checked the antifreeze and it was good. I will check the oil in the am when it is cold. FYI, I just changed the oil about a month ago and put the rev-x in it.

[John Anderson]

Definately check your fuel pressure. You are describing classic fuel pump going out problems. I have two 6.0's in the past couple of years that the pump start and stop working almost at random. The first one drove me nuts till I drove it for a week with the fuel pressure gauge hooked up.

When the fuel pump is taking a dump the trucks will idle perfectly, start great, and then randomly crap out once you get them under any load.

[Bob]

Here is the latest. For about 2 days it was pretty consistent a slight miss and doggy off the line. Results of checking the oil are that the oil level is rising. "Fuel in oil?" I then drove 275 miles. It ran great all the way. When I got home I checked the oil again to find the oil level even higher. I then took it to my local diesel shop. We are looking at a possible injector problem of some sort. And the cause...fuel pump. I will keep you posted

[Bob]

From the shop: Oil sample shows 12% dilution...thats alot of fuel in my oil. This occured in less than 3000 miles. Currently pulling injectors to check and replace o-rings and crush washers. If nothing visible plan to have injectors tested. Mechanics tells me if that is all good, then it could be a cracked head. Hoping for the best. No word on the fuel pump yet. I test drove a 2011 6.7L yesterday, man that was sweet. Awsome power. May be my next move. Ha Ha

[Bob]

The shop found a bad crush washer in cylinder #4. Got it back and it runs great. I will be tearing the fuel pump out this weekend to clean and inspect it. Thanks for the input.

[StripperDJ]

Glad you got something figured out with it...keep me posted if i can help you with it.

[Bob]

Brad you were a great help when I talked to you on the phone. I can only hope that my travels may bring me to GA some day. Thanks again for all the help. Bob

[ssredrino]

check your oil to coolant temp

mine did this same thing when it gets warm the oil gets to hot and the injectors start mis-firing, my truck was not overheating but the oil temp was running 30-40 degrees hotter than the coolant


change the oil cooler flush the coolant system

check for a bad injector harness also