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Hot miss, idle and cruising low RPM
Long post, sorry..
I've got a 2005 F350 that just had a bunch of work to it, before I bought it.
The truck had just got head gaskets, studs, 2 new heads, 8 new injectors done and then quit running after 3 weeks. I picked the truck up for a good price and started to diagnose the issue.
The truck failed the bubble test very badly, then failed the balloon test on the passenger side. It ended up being injector 7 had backed off, lost the copper washer and blew the fuel o-ring.
The injectors were all Dtech remans. The shop that did the work agreed to warranty my parts and let me do the labor (I'm an HD mechanic, but not familiar to the 6.0). I replaced the Dtech with an Autoline, all the shop could get from the supplier without waiting a few weeks.
After installing the new #7 injector I decided to check the torque on the rest. When I attempted to torque #5 it felt like it was loose too! But I went ahead and torque it to 28ft-lbs and it didn't fail a bubble test so I left it. #3 and #1 felt like they were around 10-15ft.lbs.
The standpipes and dummy plugs were all updated and the orings looked great so I put them back together. After reassembly I cranked the engine over without the key to help prime the oil rails. Truck started with about 15 to 20 seconds of cranking with the key. For the first time I heard the truck running and it sounded great but was missing a bit, while the oil rails filled, I thought great!
I didn't want to chance the other injectors being loose so I pulled the drivers side valve cover off to check torque and they were all around 10-15ft pounds, but #6 felt a little looser. As I was torquing the last injector, #8, I went back to double check the torque and it started to spin again. It ended up being part of the cast head broke free around this bolt hole.
So, got the head warrantied, pulled it, new head gasket, had the injectors out so I re-ringed and copper washered them. Installed new head, injectors, back together and fired it up, started after 15 seconds or so now I felt better knowing all the injectors were torqued properly.
Ran it and drove it to try and get any air out of the oil rail. Truck always fires right up but once at operating temperature it develops a miss. I had contribution balance codes popping up for 5, 7, and 4 I think, cleared them ran it a few times. 5 seemed to be the most common and I stopped getting codes on the driver side so I decided to pull the passenger valve cover to re-seal the orings as I had some left from the gasket kit. Injector 5 had very little copper washer left and carbon below the fuel o-ring but it was basically intact.
Swapped injector 5 with injector 3 and also re-sealed 1. And reassembled everything.
This is where I am now.. still a warm/hot miss. Always on 5 more often with 7 and sometimes 6. With contribution/balance codes. Also had a few from 2 and 4.
So I was thinking ficm or wiring. The hot part had me questioning it but the battery light was on, even though the alternator seemed to be putting out proper voltage.
I ended up replacing the ficm and alternator because I was having charging issues and had no history of the current ficm hoping that would cure my miss, the ficm was putting out 47.5 to 48v at all times though I questioned the logic side of the unit. Harness wiring checked out ok. Voltage regulator was gone in alternator.
So here I stand:
48V, 13.6V charging, truck starts right up cold and runs great until it gets warm/hot then starts missing on 5 and sometimes 7 or 6. Always on 5 even though I swapped 5 with 3. If I crank the engine over with the key out of the ignition I can't hear any dead spots in the engine.
I had a EBP sensor low fault which I replaced the sensor and it cleared. I also ruled out the ICP today, it's missing at around 640psi and tried another good sensor.
The miss is at idle or when cruising below 2000 RPM. I would really like to do a power balance test but don't have the tools for it right now, might try and get some next week.
Does anyone see anything I'm missing here? Is it most likely an injector? I'm going to pull the passenger valve cover again tomorrow and run with it off to inspect rockers and pushrods on #5.
Sorry for the long post. But trying to cover my bases.