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A few more data points from testing this morning. It was 31F, so I ran the cylinder contribution test at startup to see if I had any weak injectors and things looked nice and balanced, both compensated and uncompensated. I got the vehicle up to operating temps around ECT = 185 F and EOT = 188F and pulled WOT up a grade. EPB = 48-49 psia and MAP = 38-39 psia even though the vehicle had the same stumbling and loping at the low end when the EGR became active. Got home and ran the IDS turbo test and EGR test, both of which met the test specs. I then ran the cylinder contribution test both compensated and uncompensated and it ran smoothly and I couldn't see any difference in RPM variations on the test. When I'd manually shutoff each individual injector, each one would contribute a -40 RPM change and obvious misfire. Next, I put the vehicle in drive, applied the brake and slowly increased the throttle. It didn't take a whole lot of load before an obvious miss was present. From the cylinder contribution below, you can see cylinder 1 and cylinder 3 had misfires and cylinder 3 actually produced a P0269 contribution code. Looking at the plots, I'm unsure why cylinder 1 didn't as well. Also, if I turn off the EGR and run the cylinder contribution test in park or in drive, I don't have the misfires.
I guess the question is have I been dealing with multiple issues? I originally had an EGR valve P0404 code and inspection showed it was stuck open. This latest testing suggests I may have a fueling issue as well, perhaps a FICM issue or injectors.
Last edited by hanoverclarkegs; Nov 8, 2025 at 03:17 PM.
Reason: add plot
Is the cylinder contribution code caused because the fuel/air ratio is rich due to the EGR being commanded open. It sure seems like it since shutting off the EGR revolvers the cylinder balance issues on the IDS cylinder balance test.
Update: I pulled the EGR cooler and tank tested the coolant loop and it started leaking to the exhaust side at about 11 PSIG. The exhaust side was pretty plugged with soot and I think I was getting low flow throught it when the EGR was open which likely cause the loop instabiliy with the VGTDC/EGRDC/EPB_A. The EGR didn't look wet. I ended up cleaning the intake manifold as well...what a messy job. I purchased a BPD EGR cooler and a Ford Oil Cooler. So my question is since I had to pull the EGR cooler to diagnose it as the problem and didn't perform a coolant flush beforehand, is there a practical way to flush the cooling system without reassembling. I obviously don't want to do a flush after I install the new oil cooler and plug that up. Interestingly enough, my deltas never exceeded 10F when under load.
Mark,
Given my update finding the EGR Cooler with a minor leak, do I install the new EGR Cooler, perform a flush on the system and then just plan on tearing back apart and replacing the oil cooler?
The slight black substance in my degas bottle was likely soot from the leak. Is there any circumstance where I wouldn't replace the oil cooler? Talking with the previous owner, he had a lower radiator clamp fail from corrosion and before he knew it, he was overheating. The Ford dealer looked at it and they determined no damage had been done, but I suspect either they were mistaken or a latent failure occurred due to heating cycles. As I've stated before, my deltas have never exceeded 10F.
Mark,
Given my update finding the EGR Cooler with a minor leak, do I install the new EGR Cooler, perform a flush on the system and then just plan on tearing back apart and replacing the oil cooler?
I finally got the EGR cooler and oil cooler replacement completed. Cleaned the turbo again and the egr valve. Went for a test drive long enough to get to operating temps and was running ECT = 181 F and EOT = 185 F. Gave a couple of hard pulls and was generating 22 PSI boost. I did notice this whole drive that the EGR was not even turning on.
I got back to the garage and cleaned up my mess, then went back for some additional testing. As soon as I backed out of the driveway, I felt the stumbling again and lots of black smoke. I got on the highway and the VGT was all over the place, yo-yoing between 40% and 85%. I barely had enough power to make it up a slight hill, so I pulled over, shut the truck off and disconnected the EGR valve. Truck ran fine without the EGR connected. I'd sure like to know what is causing this problem.
I guess this is more for @bismic or @Too Many Toys is there a chart or flow diagram that shows the strategy of the inputs the PCM uses to operate the EGR valve? If the PCM is in fact commanding the EGR valve open then that is either a result of the inputs, or the PCM is just doing whatever it wants which is hard to believe. I would be willing to bet it’s an input or inputs being out of range.
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