2002 7.3L 4x4, 154k miles.

Where to start..On vacation this summer HPOP fitting, I had fixed before we left, blew out, no threads left (good thing I didn't pay that bill before I left). So, had to replace HPOP in a parking lot on the side of the road. Since then, on occasion, randomly, after it has been running/driving for quite a while, stop turn off truck, come back 5 minutes or so starts and idles extremely rough. Turn off wait a second to a few minutes, some times it starts/runs fine, sometimes it takes 2-3 times of starting/turning off to get there.
Since HPOP replacement, I have put new orings on and cleaned IPV, cleaned HPOP resevoir, checked all connections, etc.........

When its running its runs awesome.

Any ideas?
Thanks in advance.

 

Check your glow plug relay, and glow plugs

 

Moved to the 7.3L PSD forum.

Stewart

 

I'm not certain I under stand "IPV". I assume you're referring to the IPR?

When you say you cleaned the IPV, please explain the depth of your cleaning. I know of resealing the IPR.

The IPR suffers mostly because of the lack of maintenance (Oil & Filter). And, of course, time and wear.

Are you using the correct oil?

Is it at the required level?

Do you use an additive?

Does it start cold (ambient temperature) without issue?

Have you monitored the IPR, ICP, and ICPv? That would provide some insight as where to begin.

 

Thomas White,
Correct, I meant IPR.
I meticulously maintain my vehicles.
Oil=Rotella T, since I purchased it with 65k miles.
Motorcraft Filter. Change every 4000mi.
I have not used an additive until after this issue started. A local diesel tech recommended "Hot Shot" I added that this past oil change. Runs noticeably quieter, thats about it.
Have not had any issues starting "cold".
Monitor IPR, ICP, ICPv? I will guess I need a diagnostic computer for this?

 

Your description can be indicative of several circumstances. It could be the IPR, or an Injector O-Ring, an issue with Boost, Fuel delivery, or another sensor not working properly drawing down the Reference Voltage, etc.

Before you begin to "throw parts at it" which can lead to a Second Mortgage on a 7.3L, some firm data should be collected to move forward. Perhaps you know someone with a Scantool capable of performing what's necessary.

There are Android OS Software used with Bluetooth Dongles and some laptop computer software / hardware bundles as well. Anywhere from say $12.00 - $1,200.00 for most and even more for additional bundles.

Tools Needed: OBD-II On-Board Diagnostics, Phase 2 Vehicle Media Communications Unit (Scantool), or Android OS Software: Torque-Pro with Bluetooth OBD-II Connector or, Scan Gauge II - X-Gauge.

1. Select the parameters indicated from the Scantool parameter list and monitor while cranking engine and while the engine is at OT.

Data List Monitoring Parameter:

2. V-PWR: Need to ensure the Batt Voltage does not fall below .10.5 VDC Minimum. (The CMP may fall out of the PCM circuit if vehicle voltage falls below 10.5v). This can also occur several minutes after the vehicle is started as Glow Plugs and EBPV' perform their designed functions. V-PWR indicating a low voltage condition, check battery voltage, charging system or power and ground circuits to the PCM.

3. RPM: If, for some reason, the vehicle's RPM's drop below a few hundred the engine can hiccup or stall. If, it can't maintain 100 RPM Minimum (0 - both the IPR, ICP, and CMP Suspect)

4. ICP: The ICP on a cold engine should not fall lower than 500 PSI or 3.4 MPAM Minimum the ICP should steadily climb during cranking. This indicates a healthy HPOP depending upon how high it climbs. However, with EOT 140*F and AIT > 50*F a ICP of 450 - 550 is normal when stopped. The IPR % generally, during a stop should not rise more than10% - 15% and more importantly be steady. 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.

5. ICPv (KOEO) Spec 0.20v - 0.30v : It's important to validate the ICP's Voltage at KOEO to ensure it is within specifications.

6. FUEL PW: 1 MS - 6 MS (<1 / >6 IDM Suspect) This is a snap shot of the "injector on time" commanded by the PCM.

7. DC% - Cranking NTE 20% / 65% is closed. (IPR Suspect)

9. RPM - Low RPM could be an indication of starting / charging system problems **

10. No RPM indicated with the engine cranking - could be CMP circuit fault, check for DTC’s.

11. 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.

12. Because the PCM adjusts injector output based on oil temperature information received from the Engine Oil Temperature sensor and turbo boost information received from the Manifold Absolute Pressure (MAP) Sensor, and the Barometric pressure (BARO) sensor.

12a. These corrections are necessary to meet emissions requirements and to optimize power. MAT: Manifold Air Temperature The PCM uses this signal to adjust fuel and timing.

Hope this helps,

Tom

 

For something that random my first thought is 42 pin harness. It drapes across the DS valve cover where it can chafe underneath, resulting in intermittent shorts. Loosen bolt on connector, pull back the harness and check it out. If it's not worn thru yet slap a length of split heater hose over the harness to protect it for the future.