I have a 2000 Excursion with the 7.3L. We bought it in February of last year with 81,000 miles on it, and it has 111,000 miles on it now.

I'm experiencing 3 problems that I'd appreciate your thoughts on what might be going on here. I have my suspicions, but don't have a ton of experience with diesels so I'm looking to either confirm my suspicions or point me in a new direction.

First problem:

It threw a code today: P0683 indicating a communication issue between the Glow Plug Control Module and PCM Communication Circuit. Other than the code, the truck isn't doing anything out of the ordinary today. Drove it about 40 miles, up to 80 MPH, problem three below did show it's head once, but other than that it ran great.

Second problem:

Ever since we've owned the vehicle it has done a strange surging/near-stalling thing (for lack of a better word) when it's started up. It only does it occassionally, and the problem seems to appear, and then go away for several weeks or months only to reappear. Here's how it goes:

1. Start truck
2. After starting the truck immediately begins to surge (rev?) and then nearly stall.
3. It will do this over and over, about one surge/near-stall cycle per second, until I tap the accelerator, at which point it stops immediately. So far it has never stopped on it's own, but has always stopped with a tap of the accelerator.

Up until recently I chalked this up to "huh, that's weird" since the truck has otherwise run fine.

Third Problem:

Every once in a while the truck will hiccup while it's up to speed. It only seems to do it at highway speeds, typically between 55-70, and the hiccup typically only occurs once.

The first time I distinctly remember it happening was right after I had replaced the Camshaft Position Sensor (approximately 5-6 weeks ago).

While digging around online I found one other guy say his truck started doing the same thing after replacing the CMP in his F250 with the same little plastic gray one I used. So that problem might be caused by that part.

My Thoughts:

It seems like the run-away favorite for fixing problem one is to replace the GPCM. I've dug through a couple hours of forums this afternoon/evening, and it looks to me like the GPCM is the culprit the vast majority of the time when code P0683 comes up.

I'm thinking problem 2 might be an ICP issue. I can't find any previous forums anywhere that describe the exact issue I'm having - or really anything very close. Maybe it's out there, but I couldn't find it. So I'm really grasping at straws.

Problem 3 could either be related to the ICP (if problem 2 is an ICP problem) or it could be due to the new CMP I installed (the cheap gray plastic one from Autozone). It's possible the hiccup has been around longer than I think. Half the time when it happens (or does it?) I can't decide if it was a hiccup or a bump on the road I didn't see. I am sure it's happening at times, but there are other times I'm not sure if it was a hiccup or a bump I just didn't see. So I think it's possible it's been going on longer than I realize, and I noticed it that first time because I had JUST been under the hood and pretty finely attuned to how the truck was running as a result.

So what are your thoughts?

I'm about to hitch my 35' camper to this truck and haul it a few hours and I'm not feeling real confident right now. Problem 1 hit today, problem 2 is more prevalent than every right now, and problem 3 has been hiccupping for 5 or 6 weeks. I'd like to get at least problems 1 and 3 sorted out before hauling 8,000 lbs if possible.

 

Does the Code re-activate once it's deleted?

Often, just a glitch can cause such a code. The P0683 code is a Generic Code in itself without additional codes being set.

Some issues that it "could" be are:

Open or short in the wiring from the PCM to the GPCM, to the bus bar, or from the bus bar to the glow plug.

Failed glow plug

Loose or corroded connections

Failed GPCM

Loose or corroded connections on the glow plug solenoid

Glow plug solenoid failure

Insufficient battery power to solenoid

Code P0670 may accompany this code. This code points to the wiring harness from the GPCM to the solenoid as a problem.

Normal: The EBP Sensor and EPV work in unison to warm the Engine Faster to OT. It is PCM but not to the extent that it "hurts" fuel mileage. There is additional fuel delivered to maintain an increased idle while active. However, when the Tube is blocked, it does not allow the pressure transducer to fluctuate by the exhaust pressure. All this is controlled based on following parameters:

IAT (Intake Air Temperature) Below 10°C (50°F) to activate EBP
EOT (Engine Oil Temperature) Below 70°C (158°F) to activate EBP

A high pitched whine, in exhaust system, will be heard when EBP device is active.

At the turbo exhaust outlet is a butterfly that when actuated will restrict the exhaust flow, this causes the engine to work harder in cold ambients and generate engine coolant temperature quicker for cab heat.

The actuation of this device is controlled by the PCM and the E8P regulator located in the turbo pedestal. The EBP regulator restricts lube oil flow out of the turbo (center housing) and directs oil to the turbo pedestal which pushes the EBP actuator arm outward causing the butterfly to close or restrict exhaust flow.

The PCM uses the EBP sensor to monitor the exhaust restriction. The E8P sensor is connected to the right exhaust manifold using a pipe and fitting.

The exhaust back pressure device will open when the accelerator pedal is depressed and the exhaust back pressure increases. When the exhaust back pressure decreases or the vehicle is in a steady state, exhaust back pressure decreases per the EBP sensor, the E8P regulator can, and will activate the EBP device again even while going down the highway as long as the EOT temperature is below the specifications.
It is quite probable the CMP you installed is the culprit. CMP Sensors have caused great grief amongst the 7.3 Owners. The Part Numbers associated with each is:

Black CPS P/N: F7TZ-12K073-A
Grey CPS P/N: F7TZ-12K073-B
Dark Blue CPS P/N: F4TZ-12K073-C

Several people claim the Dark Blue and Black are Best while others say the Grey is best. What I have found is that the only way to know which one provides the best performance for you is to try them.

If you still have the old one, reinstall and see what happens.

 

1. GPCM is highly suspect, if the code returns after clearing.
2. This can be ICP sensor, backpressure sensor, backpressure valve, a tune, injector O-rings, etc.... More testing is needed on this one - maybe a scan tool/gauge.
3. This can be a non-OEM CPS or air in fuel, but a bad CPS would throw a code.

 

Thanks for the replies.

1. I'll have the P0683 code cleared and see if it comes back. Right now it isn't accompanied by any other codes.

2. The issue happens as higher temperatures than the thresholds listed. We're in Raleigh NC right now where it was 91 degrees yesterday. However, other than that it sounds like what you (Thomas White) describe could be the culprit. When I take my foot completely off the gas at around 50 mph and am coasting downhill I can hear the engine flutter - could be the exact same behavior I'm seeing when I start the vehicle. Makes me think perhaps the back pressure valve itself is acting up. Does that make sense?

3. The CMP I installed is the gray one. The old one was the original OEM part. However, it was causing the truck to stall and had thrown a code indicating it needed to be replaced, so I tossed it when I replaced it. I think I'm going to buy either the black or dark blue one and see if that fixes the hiccup.

How would I check for air in the fuel?

 

Black ones are near impossible to find. The blues can be had at the local International dealer, I hear. If that gray one you bought isn't a Ford one, and is aftermarket, you can almost bet it is causing some of your problems. It will really do funny things when it's raining and you are running the wipers...

 

Haven't noticed any relationship between it acting up and the wipers - but it is aftermarket. We needed to get up and running that day so I took whatever Autozone had on the shelf.

 

Do you have access to a ScanTool? You will need one with an Enhanced Data System.

In order to properly rule in or, rule out what the issue is or, is not, we need some data.

When you acquire one, select the parameters indicated from the Scan Tool parameter list and monitor while cranking, Cold, and at OT.

Data List Monitoring Parameter:

Vehicle Power (V-PWR) 10.5 VDC Minimum.

RPM 100 - 150 RPM Minimum while cranking 99/00MY (0 - CMP Suspect)

Injector Control Pressure (ICP) 500 PSI or 3.4 MPAM Minimum

Injector Control Pressure Voltage (ICPv) Key On Engine Off (KOEO) Spec: 0.20v - 0.30v

Injector Control Pressure Duty Cycle (ICP %) Spec: 10%-12% at idle, engine at 140F or > / NTE 20% while Cranking / 65% is closed (IPR Suspect)

Fuel-Pulse-With (FPW): 1 MS - 6 MS (<1 / >6 IDM Suspect)

Exhaust Back Pressure (PSIG)

Manifold Absolute Pressure (ATM)

Mass Fuel Desired (MFD) (mg)

*V-PWR - If indicating a low voltage condition, check battery voltage, charging system or power and ground circuits to the PCM.

2. ICP - A minimum of 500 PSI (3.4 mPa) is required before the injectors are enabled. No or low oil in the reservoir, system leakage, injector O-Rings, or faulty IPR could cause pressure loss. You can disconnect it from the wiring harness. The PCM is programed to use a Delta of 700 psig. Driving the vehicle while disconnected is not recommended.

Note: If no RPM signal is received, IPR duty cycle will default to 14%

3. FUEL PW - Even though a 1 to 6 mS FUEL PW is shown, it’s possible the IDM did not receive the signal due to a CI or FDCS circuit fault or internal IDM failure.

Hope this helps,

 

Aftermarket CPS, eh? I'd get an OEM in there, they're inexpensive. I bought mine at Riffraff diesel, but they can be acquired at the counter of Ford or IH.

Once the new OEM CPS is in, you can retest for items 2 and 3.

 

Going to be trying that this weekend to see what happens. Also, the check-engine light went away yesterday. Going to make sure all codes have cleared and then wait to see if it pops back up.