Hey guys. I'm starting a new thread because my last one was getting kind of long and people didn't really feel like reading through all of the pages. So here is the new thread.

A couple of weeks ago I started my truck up and it ran fine for about 10-15 minutes before it suddenly died. I checked the oil and it was pretty low so I immediately changed it. When I went to restart it, it again ran fine until it warmed up and would die. Some times it will die at idle and other times it will die if you try and touch the gas. It does not throw any codes and will not restart again until you let it cool down. It was working fine the last time I used it (it sat for about 2 weeks). I've never had this type of issue before and the truck has never shown signs of malfunctions. As mentioned earlier, this is a second post so here is what I have done so far:

Parts replaced:

Replaced the IPR
Replaced the CPS (Not OEM but didn't change symptoms)
Fuel filter
Fuel pump
Hutch/Harpoon Mod

AutoEnginuity tests ran:

KOEO:
- Test Completed Sucessfully

KOER:
- P1211 Injector Control Pressure Higher/Lower Than Desired

KOER Glow Plug:
- P1397 Variable Valve Timing Solenoid B Circuit Low Input

KOER Cylinder Contribution:
- Test Completed Sucessfully

Readings while cold:
IPR Duty Cycle - 14%
IPR Voltage - 1.2
ICP - 800 psi

Readings while warm at idle (it let me run the numbers before it died):
IPR Duty Cycle - 11.72%
IPR Voltage - .9
ICP - 500 psi

Readings at 2k RPMs (not sure if the motor was warmed up or not but it eventually sputtered and died)
IPR Duty Cycle - 20%
ICP - 1200 psi

Other tests ran:

Injector harness ohmed out good
HPOP gear bolt is tight
Took out fuel filter and visually saw the fuel bowl fill at a good rate

What else could there be?

Bad HPOP
Leaky injector O-ring
Bad ICP <!-- / message -->

 

Come on guys I know there is someone out there with some advice. What would you do to go about testing the injectors for leaks and whether or not the HPOP is doing its job?

 

Truck still out of comission. You know what really sucks about this problem is that I have found a bunch of threads over the internet where people were having EXACTLY the same problem as I am having and the IPR fixed just about every one of them. That was the first thing I did and it didn't work. What are the chances that the IPR that I put in was bad, or, what could cause the IPR not to function correctly?

Right now I am in the process of changing out the injector o rings. I've got the driver side done and will work on the passenger side this weekend. Started it up after changing the driver side and it still died.

 

Can you monitor icp after it dies while cranking? If you don't get around 500 psi the injectors won't fire. Since you are doing injectors you might want to check the armature plate clearance: http://www.dieselpro.ca/Poppet%20Valve.pdf

In my signature under the ford doctor link there is a good hpop guide for our trucks. Hopefully others will have some more ideas.

 

Have it in the shop right now. Didn't want to do it but I'm getting pretty tired of throwing parts at it.

 

It sounds like you have extremely low fuel pressure. It will run "fine" when the engine is cold, but as soon as it warms up, it will start to miss, etc. My suspicion is that when it's warm and you're hitting the gas, the fuel pressure is very, very low.

It may be caused by a blockage in your fuel line from the tank, or a gunked up pickup foot screen (in the tank). You could remove the fuel line from the tank to the pump, and blow air back towards the tank to try and block any obstructions. Make sure your fuel cap is off when you do this, and if your tank is full...just a short burst, otherwise fuel will spill out.

Could be a dying fuel pump.

Have you checked your fuel bowl lately? That is, under the filter? Sometimes you can get A TON of sediment and crap in the bottom of the bowl, and it lets just enough fuel through to idle, but not enough for more than idle. A friend of mine once bought a F350 CC Dually for a song because of the exact problem you're talking about. He cleaned out the fuel bowl, ran like a champ.

That's all I got. Please post up what the solution is, once it's figured out!

 

Update for you guys:

Problem still not fixed. Took it to a shop where they have some VERY experienced Ford diesel mechs. Just got off the phone with them and they are pissed because this is the first 7.3 that they have never been able to figure out. This is what they have come up with though: they say that there is an issue between the PCM and the IDM. They put in a donor IDM and it didn't fix the problem. They say that they cannot read the specific between the two because they don't have the equipment. Here is my thought: How in the hell can something like this just happen right out of the blue? I'm skeptic about this being the issue. Also, if there was a communication error between the two, wouldn't it throw a code stating that there was a problem? This thing is getting out of hand.

 

Sorry, it was between the FICM and the PCM. The code they were chasing was 1670 and they tried a new FICM and it didn't fix the problem.

 

Have you checked the hot oil pressure (low-side - not HPOP)?

 

Watching this intently. I changed my injectors over to SS last year and changed the IPR at the same time. I had it on the shelf and it was easy to get to with everything out. Anyway in stock tune after it warms up it wont idle. HPOP pressure goes towards 300 psi truck starts to die and it recovers itself 500 psi and idles normally for a second then does it again. In any other tune besides stock it doesnt do it. I just start it in stock then switch tunes as it warms up. I havent taken the time to mess with it yet. please let us know what you find.

 

You were right the first time. We don't have a FICM. They started using those on the 6.0. We have an IDM.

Got a chip in the truck? What are your ICP psi, IPR duty %, rpm, injector pulsewidth ms, battery voltage, vref, and EOT readings while cranking when it's hot and won't start?

While it's cold and running, can you grab and wiggle any wiring and make it stall? ICP, IPR, main engine harness, wires over the driver front shock, etc.

Can you watch EOT and see if it always stalls at the same temp? If so, what temp is it? Also, what temp does it have to cool down to before it will start again?

Were you sure to lube up the IPR o-rings very good before you installed this new IPR?

 

No on this, can you please explain?

 

Yeah, I realized the FICM thing not to long after posting, IDM not FICM.
No chip but I do have Edge (not sure if that classifies as a "Chip")
Take it with a grain of salt, but the mechanic told me that every indication he got from the truck (ICP, IPR, voltages, everything) says that it should be running.

I think what we need to start thinking about is "What can happen to a truck that has been sitting for two weeks that may cause this type of problem?" I say this becase nothing was done to the truck when this issue surfaced so it's not like going back to the last thing you did. One thing that I haven't tried is cleaning the bottom of the fuel bowl.

Would it be possible that sediments are restricting fuel flow from the bowl to the injectors? And no, I do not have a fuel pressure gauge.

 

Originally Posted by SteveH-CO View Post
Have you checked the hot oil pressure (low-side - not HPOP)?

Your LPOP feeds your HPOP, and without sufficient oil, your HPOP won't function. It's an easy test to check the low oil pressure, which is what you'd call the regular oil pressure on a gas engine. I would just check it as part of ruling out any other issues. More than a few people on this forum have had to replace the LPOP - search for some of the stories.

 

I had the same issues years ago. Was a bad injector. Once the oil got warm it would leak past the poppet and cause a no start.