My 2004 Excursion 6.0L started having loss of power problems recently. The truck is stock and has been studded. I was on my way home from work, so this was about 25 minutes into my commute when I felt the engine stumble, then recover. This happened a couple more times over the next 5 minutes. I had my Torque Pro app running and ECT = 190F and EOT = 196F. Fuel pressure = 57-60 PSI. When I got home I hooked up my laptop and ran the IDS power balance test to see if I was having any injectors dropping out and things looked fine both compensated and uncompensated. I pulled the DTC's and had a P0672, P0678 and P0148. I've recently had cold start problems (rough idle until it warmed up) during the -10F mornings we've had 2 weeks ago, so the P0672 and P0678 codes glow plug faults make sense. At that time I figured I had some stiction problems because if I plugged the block heater in, it'd start with no problem and idle smoothly.

So yesterday I went for a drive and about 20 minutes into it, I felt the brief stumble again at 60 mph, then a hardly perceptable shudder was present, in fact I was wondering if I was imagining it. A couple hard accelerations seemed normal. I was at a stop light and went to accelerate and almost no response to the pedal, just enough to get me out of the intersection. I was about a mile from my dad's place so I thought I'd limp it there. The power returned after about 10 seconds and I took it easy until I got there. I pulled the DTC's and had P0672--Glow Plug Cyl 2, P0678--Glow Plug Cyl 8 and P0404--EGR Control Circuit Range. I pulled the EGR valve and it was caked with soot, so I cleaned it. I also pulled the injector cable harness to inspect it for chaffing, which visibly looks fine, but now needs to be replaced because the FICM connectors broke. Inspection of the Engine Control sensor and fuel charge wiring harness (sensors, glow plug, EGR, etc) revealed a wire that had worn through and shorted to chassis on the EGRTP actuator pigtail.

Of note, the lack of power response to the accelerator occurred 2 times on a December Pheasant hunt, but at the time I thought it was because I had my clumsy size 13 hunting boots on and was pushing on the top of the pedal instead of the bottom and the pedal really wasn't moving. So, I'll fix the chaffed pigtail and replace the FICM injector wiring harness and see where I sit. Any other insights on what else to look for would be greatly appreciated.

Other noteworthy thing I forgot is that prior to the inirial problems this week, I was attempting to log a cold start on Torque Pro and most of my PIDs quit streaming data, I was only getting RPMs occassionally. An app reset and dongle unplug wouldn't restore the data stream, but a ignition cycle did. BTW, when I had the loss of power issues, nothing was plugged into the comm port.

 

Well, this problem has reared its head again on my 2004 Ford Excursion 6.0L. Oil changed with Rotella T6 2K miles ago. I was doing a lot of starting/stoping on a hunting trip when the truck started stumbling at about 20mph. I had just let off the throttle then got back into it and there was very sluggish response until the RPM's got above 1800 or so, then there was plenty of boost topping out at 24 PSI. I had come to a stop then tried to accelerate and the turbo would lope and puff smoke out the pipe, then when the RPM's got high enough there was plenty of boost. When it is in this mode, the VGT pegs at 85% until the RPM's get high enough. This happened half a dozen times over the next week of my trip. On the way home I could smell sulfur for a couple hundred miles of the trip which I assume was from the catalytic converter. The truck is now experiencing these drivability issues when the ECT/EOT get above 150F. I cleaned the EGR thinking it might be caked in soot, but it wasn't bad at all with a light layer of dry soot. I did notice I move the valve fairly easily and it wouldn't snap closed completely. Thinking I might have a bad EGR, I ordered a new on from Ford. I drove the truck to work for a couple of days with no issues. It has been a 120K or so since the turbo had been serviced, so I removed it to check/clean the unison ring and VGT vanes. Not much for soot and the ring/vanes moved freely. I cleaned and reassembled then went for a test drive. As soon as the temps got above 150F, the stumbling started again. If I disconnect the EGR connector, the truck responds normally with no stumbling issues. I've ran the IDS power balance test to see if I was having any injectors dropping out and things looked fine both compensated and uncompensated. Here's some of the basic sensor values KOEO using IDS: BARO = 14.2 PSI, EBP = 14.1 PSI, MAP = 14.2 PSI, Fuel Pressure = 65 PSI. Codes present P0404

I did run the following test using IDS.




Any help troubleshooting this problem would be greatly appreciated.

 

Is your '04 Ex equipped with the 2003 engine or the 2004 engine (ICP on the passenger valve cover)?

Your P0404 code could be coming from running w/ the EGR valve unplugged. Is the EGR valve wiring connector and wiring itself in good shape?
Clear codes and see if the P0404 comes back (leave EGR valve connected).

 

Also, at KOEO on a completely cold engine, what are all your temperature values:
EOT
ECT
TFT
IAT1 (or just IAT)
IAT2

Both the IAT2 and MAF sensor (which contains the IAT1 sensor) are critical for determining EGR flow.

 

04 Ex has the ICP on passenger side valve cover.
Cleared DTC's and started it up and drove it until the engine warmed up and the stumbling began. Pulled DTC's and P0404 was back.

KOEO readings with IDS after sitting overnight.
BARO = 14.3 PSI; BARO_V = 3.29 Volts
EBP_A = 14.53 PSI: EBP_V = 0.88 Volts
MAP = 14.35 PSI; MAP_V = 1.27 Volts
ECT = 60.8 F; ECT_V = 3.94 Volts
EOT = 62.6 F; EOT_V = 3.93 Volts
IAT = 60.8 F; IAT_V = 3.42 Volts
IAT2 = 59.0 F; IAT2_V = 3.95 Volts
TFT = 56.4 F; TFT_V = 3.58 Volts
ICP = 0.0 PSI; ICP_V = 0.23 Volts
MAF = 0.0 g/s; MAF_V = 0.04 Volts

Using IDS to control the EGRDC %, EGRVP_V doesn't track with the commanded EGR % and in fact doesn't move from it's startup value of 1.5V. I stubbed in my old EGR and EGRVP tracked EGRDC as below:
--EGRDC = 0%; EGRVP = 0.84 Volts
--EGRDC = 99%; EGRVP = 2.45 Volts
So it seems the new EGR valve has stuck open...I'll pull it when the engine cools. I guess it's also possible that the wiring harness has an issue and when I stub in my old EGR the harness is in a different position that flexes or compresses wires. BTW the old EGR gets stuck in the open position when it hits the end of travel and I have to give it some convincing to retract.

 

Update: Removed the EGR and it was indeed stuck open. It was covered in soot, but it wasn't wet or pasty. I cleaned it off with carb cleaner and a toothbrush, which freed up the pintle. I was able to use IDS to control it, but the feedback didn't respond until about 40% and then the EGRVP wasn't a crisp step, but a slow rise to final position. This EGR was only in the vehicle for 2 days before it stuck open. So the real question is why is the valve coking up? I parked with the front of the vehicle down slope and saw no evidence of moisture in the bottom of the EGR port. I imagine if the EGR cooler had a minor crack that it might not leave an indication. Is there a way to pressure test the EGR without pulling it? I did pressurize the cooling system with 15 PSI and it held that for the 30 minutes I gave it. Maybe that's not long enough or the cooler needs to be at operating temps. I'd like to pinpoint the problem before I jump into replacing the EGR cooler and Oil cooler.

I indicated in post #2 that there was a Sulphur odor for a couple hundred miles when this problem began, so I'm wondering if a restricted catalytic converter could lead to excessive coking of the EGR valve.

 

I suspect you don't drive the truck under heavy load very often. In my experience, many trucks with original EGR systems have problems with carbonization of the system. The exhaust soot in combination with the oil mist from the crankcase ventilation causes problems, mainly in engines that are used under light load or for short distances.

 

I would remove and clean the intake manifold. It's a dirty job, but necessary.

I always recommend removing the EGR cooler; a CCV reroute is also a good idea.

 

You'd be correct about heavy load towing, limited to 28ft enclosed snowmobile trailer a couple times per winter. Daily driver 50 miles round trip to/from work. About 15K miles during hunting season.

 

Finally got the EGR valve from Ford and installed it. The problem is still present and occurs as soon as the truck warms up enough to start commanding the EGR valve, which seems to be around an EOT of 158F. Lots of black smoke, laggy and huffing until about 1800 RPM. Problems don't occur with the EGR unplugged or if I take control with IDS and turn it off. Looking at the air management diagram, wouldn't a restriction downstream of the turbo manifest itself in a higher than normal EBP reading before the EGR becomes active? I'm going to perform a smoke test on the CAC system and the exhaust system to make sure I have no leaks.

 

Update: Inspected EGR, IAT2, EPB, TP Sensor, TP Actuator, VGT wiring, all seem to be OK. Went to remove the compressor intake hose and the clamp was completely loose, to the point it would rotate. Removed the hose and cleaned the MAF sensor and IAT sensor. Installed my compressor intake air intake leak fixture to perform a smoke test on the CAC system and found no leaks, although I was only able to pressurize to 5 PSI due to some hose fitting issues popping off my smoke machine. Cleaned out the MAP nipple on the intake manifold, then buttoned everything up. Went for a ride and didn't have any of the loping/chugging issues after the EGR system started actuating. It did feel a little flat and it wouldn't generate quite the boost I'm accustomed to at WOT...normally it's around 24-25 PSIG and tonight it was topping out at 21 PSIG. Is it possible that the MAF sensor was reading low due to leakage at the compressor input from the loose clamp and influencing the air managment control system?

Also, after driving hard, I measured the CAT input and output temps with an infrared heat sensor and observed the following temps: CAT input temp = 240F, CAT output temp = 220 F. Should the output temp be higher than the input if the CAT is operating properly? I did notice the CAT outlet pipe is cracked about 1/2 way around the circumference.

 

The saga continues...not sure why it wasn't acting up during yesterday's test drive, but it's back to rolling black smoke and huffing when RPMs are low and you ask for power. Again, this all occurs after the EGR becomes active with EOT around 158F and will cease if I disable the EGR with IDS or by unplugging it. Any suggestions on how to pinpoint?

 

Did you ever tried a tune?

 

No I haven't tried any tuning. Not necessarily opposed to it and had considered it, but I was happy with it in stock configuration. Something has suddenly changed in the last month to make this a persistent problem. I've never had any black smoke or huffing when requesting power until recently. It sure seems like it's starving for air when that EGR is active. I'll capture a plot of EGRDC, EGRVP, EGRTP, VGT, BARO, MAP, MAF, EPB_A, RPM, EOT, ECT. Any other PIDs of interest? I'll also pull any codes that occur while this is happening.

 

What would happen if the EGR cooler was restricted and the PCM is controlling the EGR open and no flow is occurring? Is the PCM managing the EGR throttle plate, in part, based on commanded EGR position and restricting the compressed air from the turbo?