Hey everyone.
Picked up an 04 6.0 with a blown trans with over 300k miles, popped a transmission and a PCM in it, now it shifts like it should. However, I have found the truck has a misfire at light - medium load, ie 1/4-1/2 throttle, above 1/2 throttle it mostly goes away until 3000 rpm. Truck idles great, but cruising, you can feel it bucking as if a cylinder is going in and out.

FYI, all numbers read properly, has good ICP, exhaust back pressure is reading properly, MAP sensor is reading properly, air filter is clean. Truck needs oil cooler, thermostat (coolant temp around 165 and oil temp around 215-220) and an oil change as well once i fix this miss

I dont have access to a scanner that will do a contribution test, i only have forscan (what scanner would you recommend for these truck, ford AE?). Ill start by inspecting ficm wiring, and ficm voltage. If that checks out, i will unplug each cylinder 1 by 1, and when the engine is running on a constant 7 cyl(its currently not a dead miss, it cuts in and out) i will know that is the hole that is missing. Then ill inspect valve train (Cracked rocker, or excessive valve clearance). If that checks out (hopefully it does), i will swap the injector on the missing cylinder with a cylinder that doesn't miss and see if the misfire follows the injector. If it follows, i will replace the injector. If not, i will do compression test and pull the pushrod and lifter and see if its damaged.

Just wanted to post this to show what the issue is when i find it, and hopefully that will help others who encounter this similar issue, and id appreciate any info or similar issues and what your resolution was.

I will post a video later today of how the truck acts.

 

Are you sure the ECT and EOT sensors are reading accurately?

You can pull them, clean them, and then switch them with each other as a check.

No codes?

 

I will double check those sensors before throwing a thermostat and oil cooler at it.
No codes, I put 25 miles on it last night, didnt throw any codes. Drove another 25 this morning but haven't scanned it again. Ill hook my laptop to it after work and pull codes again and post if there is any change.

 

Pulled codes yesterday after another 25 miles, still no codes. Truck runs better when it first starts up. Wont have time to mess with the truck until next Saturday, gotta do a motor swap this weekend. So I will update this thread again next weekend.

 

So you did or didn't validate the temperature values?

 

I didn't have time for that yet
Next Saturday I will start the diag process. Will figure out this misfire first, I don't want to drive it around if its a bad rocker/lifter or even a sticky injector. Once that's sorted, I will start tackling the oil temp issue (whether its sensor issue or actually poor temps)

 

Dirty oil and even hotter than normal oil (if an injector has a slight high pressure oil leak) can cause cylinder contribution issues - oil is important to injectors. High oil temperatures accelerate the degradation of o-rings. Trying to figure out cylinder contribution issues with dirty oil doesn't sound wise. Cart before the horse IMO.

If the ECT sensor is off (reading inaccurately), maybe it doesn't really need a thermostat. If the EOT sensor is off, it is impossible to know how plugged up the oil cooler actually is.

Anyway, best of luck, keep the thread updated.

 

Makes sense, I will check that for sure. Just want to make sure its nothing catastrophic before I run it for too long. Thanks for the input i appreciate it.

 

Ficm wiring looks good, and I unplugged each injector one at a time, and the truck would still do it on 7 cylinders. I can conclude this is not an issue with a single cylinder. The turbo veins have been sticking closed on me the last couple times I drove it, but the bucking issue still persists if i unplug the vgt actuator(the veins do open when i unplug it). I am going to clean the turbo anyways and see if it helps, as I've seen a couple other threads where they had the same symptoms due to stuck veins.

Ill update tomorrow afternoon after I finish the turbo up. I'll continue diag after that if that isn't the cause of the bucking issue.

 

Took turbo out last night, one vane was completely seized to the exhaust housing. So that was definitely an issue. After struggling with it for 15 minutes, I was able to get the vane off and, to my shock, the pin for it was actually cracked. So the exhaust housing is junk. I have another turbo, will throw that on there tonight. It all works out anyways, the compressor impeller was pretty gouged up from 300k miles of use.

Going to have to source a decent used exhaust housing now and rebuild this turbo.

Will update with results.

 

Alright here is where I'm at with this
Swapped the turbo out with another good one i had laying around, and now that works perfectly, moves very freely and makes proper boost.
Did an oil change and put a ford filter and cap on it.
Confirmed the oil and coolant temp sensors are working properly, swapped them and got same readings.

As for the stumble jerking, the truck barely does it cold, does it more and more as it approaches like 220 oil temp, and after 225 it goes away completely. I know those temps aren't optimal and I have a new oil cooler to throw in it once i get it working right.
It feels like the whole engine is cutting out rather than a single injector. The cutting is also entirely load dependent, has NOTHING to do with rpm, I can replicate the same behavior at 1400 rpm and 3000 rpm, it only happens between 15-40% load. If I floor it, the truck has great power, no stumbling, even in OD if i give it 50-60%, itll stop cutting out and smooth out completely.

All this leads me to think its probably a tired IPR. When i had the turbo out, looked like the IPR went through a couple apocalyptic events. Seems like its a bad coil and the hotter the IPR gets, the worse the issue with the coil gets, until it reaches that temp threshold where maybe it expands enough for the bad windings reconnect or something like that.

I have a good used one somewhere that I will throw into the truck as soon as i get a chance, and will update you all with results. (Ill post ohm results after i swap it, if it ends up being the issue)