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Discussion Starter #1
Hello all!
Let me thank everyone who has posted in the past and helped me work through what I've already worked on with my truck, to at least get me to this point. But through all the searching, I can't find the answer I am looking for, so I shall share my situation, and ask for advice afterwards.

1999 F350 7.3L ZF 6 speed

A couple weeks ago, I was on my way to work, and I was turning down a street, the engine stumbled, and almost stalled, but I got it to keep moving. As I got it to the gas station to fill up, it died in the parking lot, and after cranking, I got it to start again. I filled the tank, made it to the work parking lot with no problems, until I went to back it into the parking stall, and at that point, I was lucky to have gotten it all the way parked. I got the truck towed home and that weekend, I tore into the valve covers.
Under this initial inspection, I had found that one of the caps for the glow plugs had been broken, and I figured that that may have been shorting out on an injector. I bought 2 new valve cover gaskets, and soldered the new harnesses in - as the old ones, on each side, had seen better days. I ran the truck for a while, she seemed to run fine, and I called it good.
The following Monday, I drove the truck to town, about 15 miles, no issues. I went to the bank, deposited a check, got back to the truck, left the parking space, and as I was leaving, she died again. But with all the cranking I did, it wouldn't start up. I had her towed home again that night.
This is where I started throwing parts at her. I know, as a seasoned home garage "professional" this is not what to do. But with some of the other things I've come across in this truck, I figured new parts would not hurt anything but my bank account. She received a new IPR, ICP, CMP, I replaced all the seals in the fuel bowl (Those NEEDED replacing), and new injector o-rings. I'm happy I did the o-rings, two of them were damaged on the previous install, but not to the point off failure just yet. None of this got the truck to run, and finally came across that I needed 10.5 volts across both batteries to get the truck started. I charged them and she's fired back up.
Now this is where I am currently at. The program I have reads the ICP in kPa, at 3k-ish at idle, 5-6 k-ish at high idle (2k RPM). The old IPR ohms at 9.5 Ohms, the new IPR ohms at 12.5 Ohms. I did replace the plug for the IPR because the old one was very corroded at the back, and I figured that was shorting or doing something that I didn't want it to do - still no change.
When the truck idles, on her own, she does just fine. But as I hold the gas pedal between 1,800 and 2,500 she'll miss occasionally. When I try and snap the throttle, it's like the engine is getting flooded, and eventually will work it's way back into a normal rev, but it's a very consistent test that I can do.
I tested the fuel pressure this morning at the port for the fuel lines - 70-75 PSI, and during my throttle "test" the pressure does not change, so there is no clogged fuel line or apparent lapses in pressure.
When I looked at the wire loom, when I replaced the plug for the IPR, I did not see any other wires that could be causing an issue for shorts.

I am currently at a loss for ideas. The oil is brand new, as per required when doing the injectors. The CEL comes on for a blip when doing the throttle "test" and logs the p1211 - IPR open or closed longer than it's supposed to. What else should I be looking at?

In advance, thank you for your help!
 

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P1211 means HP oil pressure above or below desired pressure. Even though you're replaced the IPR, it could be sticky, or you could have something else going on. Did you confirm that the IPR coil nut is on snugly? If it's loose, the coil can slide back and forth, which makes the IPR act up.
 

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Discussion Starter #3
P1211 means HP oil pressure above or below desired pressure. Even though you're replaced the IPR, it could be sticky, or you could have something else going on. Did you confirm that the IPR coil nut is on snugly? If it's loose, the coil can slide back and forth, which makes the IPR act up.
That is one thing I double checked, at the time I was Ohming both solenoids, and even swapped one out for the other to see if there would be a difference.
The new solenoid held the pressure numbers more steady than the old one. I have replaced, and kept on, the new solenoid, and the nut on the back and nice and snug.

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Another question to the gallery:
This engine doesn't run on vacuum, like a gas engine does, right? I hooked up my vacuum gauge to the port that leads to the MAP sensor(?), on the passenger side of the engine bay, and ran the engine. At idle, the needle sat at 0. When I revved the engine to around 2k, the needle wasn't smooth, it had some vibration to it, but it wasn't sweeping, and made it to about 5 PSI boost. Now that I'm writing this, I don't recall that specific, but it was somewhere within that vicinity.

Is there a chance this is a boost leak type issue? Are there gaskets or o-rings I should be looking at that might cause a vacuum type issue to mess with the air/fuel ratio?
 

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No, a diesel doesn't rely on vacuum. The only reason there's a vacuum on a gas engine is because there's a throttle plate, that's not present on a diesel. The fuel on you truck is metered at the injectors directly into the cylinders. There's really not a strict air/fuel ratio on diesels. They get the same volume of air (roughly), and the power is regulated by how much fuel is injected. So at idle, a diesel is extremely lean.
If there are leaks in the air intake system, they would just affect the volume of air delivered to the engine, and it would be down on power only at max load. But it wouldn't hurt to check for leaks in the air supply. You can do that by getting a 3" plastic pipe cap from a hardware store, drill and tap it to accept an air hose adapter, clamp that affair into the intake hose to the turbo (inboard of the plastic gizmo at the valve cover, and apply about 5-10 psi of air from your air compressor. Then listen/feel for leaks.
 

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Discussion Starter #5
I'd like to add a small update:
I did the boost leak test and couldn't find any noticeable leaks.
I felt confident enough to do a road test today:
1-2 hard throttle was responsive enough. 3rd gear felt like a miss on a cylinder. 4th gear, mash on the throttle, and the engine stays at whatever RPM I shifted into the gear at. I'd have to put the clutch in and gas it a bit before I could put the transmission back in gear and continue. Noticeable cylinder miss.
Off to take the valve covers off again. But the last I checked, all were throwing oil just fine.

EDIT: on the drive test, the vacuum gauge in the cab read steady (redid the piping for it this morning as well). 3rd gear at around 3k, 12 PSI. Otherwise, fluctuated just fine as far as I could see.
 

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Discussion Starter #6
Another Update:
I found bubbles coming up from one of the glow plugs. So I tightened that one down. And I went through and double checked the torque on the rest of them, and found one that didn't want to seat right. So I chased the threads with a tap and lots of WD-40. After expelling all the oil from the cylinders, the batteries are dead again.
Currently charging. Next update pending charged batteries and time in the day.
 

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Discussion Starter #7 (Edited)
Today's update.
I started off by replacing a plug for whatever plugs in beneath the turbo, on its pedestal. The wires weren't fully destroyed, but I figured I'd change that out while I'm digging around, and just for peace of mind.

With the batteries charged, I fired her up again. Still had the stumble.

I broke down and figured I'd look at my install of the o-rings. I feel very confident that I installed them properly and will no damage, but I figured that would be the next step.

As I went to drain the oil rail, I noticed that the first one I went to was loose. Seeing as that runs a chance for introducing air into the oil line, I tightened them back down, and fired the truck up again. That right there made a difference, but didn't fully fix the problem. My lesson from this part is to double check those puppies. I can understand not wanting to strip them out, but this one was just an overlooked one on accident.

I figured the oil rails needed to be burped again. But this time, taking her on to the road, I brought the laptop along to read live data, not expecting to find much. I kept her in 1st and 2nd gear. A good amount of time at 2k RPM and up to 2,500 at times, revving along the way.

I'm not too entirely sure how I got this response, but I feel this is the key to my problem:

The top red line is the IPR sensor.
The bottom two are ICP readings.

Normally, the ICP is a very wavy form, but it follows the general flow of the IPR readings.




I was at 2k RPM when this event happened, and I tried mashing the throttle to see if there would be a change of response. But the oil pressure in the lines steadily dropped, while the IPR was calling on more pressure. Whatever caused that pressure drop, the pressure built up again and I got an engine surge.



Could this be from a failing check valve in the HPOP, leaking HPOP seals, bearings? There's no noticeable leaks of oil coming from the unit. What is the purpose of the plug on the top of the HPOP?
 

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Discussion Starter #8 (Edited)
Update:
I think I found the cause of my stumbling during revs.

Doing research on the HPOP, I found that the 1211 code can be from gunk in the edge filter. Although the specific statement in the reading material cited a different example, I figured it was close enough to my situation to clean out the HPOP and replace the o-rings.

Upon disassembly, I found that one of the lock/retaining rings for the high pressure lines that goes from the pump to the head was broken. That was the only noticeably broken part. All the other o-rings looked fine, but replaced none-the-less.

I have taken it for a test spin, and like I said, the stumble at 2k is gone. Now it is acting like I believe only air pockets in the system to exist. But as I'm driving it (it's raining out today) I finally get a quality miss in the engine, and get a code P0344. I found a post regarding a full pinpoint test, but do not have the breakout box the testing calls for.

In my initial lookings, I did pull and inspect the IDM. The pins looked just fine, and the box showed no significant signs of deterioration that would lead me to suspect water intrusion.

Unless someone has other ideas, I'm assuming that I will have to pull the whole harness again and inspect the wiring more carefully, although I do not recall seeing anything that would cause me any alarm. I did check the pins. KOEO, I have battery voltage on one pin, and 5 volts at the middle pin. Key off, I do have ground at only 1 exterior pin. But, I get a momentary blip of continunity between the center pin and vehicle ground. Is that normal? Something to do with the computer having residual power in it?

Could I please ask someone to attempt to verify that blip on their own vehicle?

Thank you for your help, both now and through the research I was able to look at up until this point on this forum.
 

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Discussion Starter #9 (Edited)
3,525Update:
Last night, I replaced the CMP plug. When finally plugging it in, I noticed it was a lot more secure than the old one. I'm wondering if that added to my collection of issues.

I'm still having an issue with the truck though. I took it for a few road tests today, hoping bleeding the lines would be a part of that issue.

Will someone please describe their experience with post injector replacement bleeding. What did the purging of air from the system do to how the engine ran? I've read plenty of places that it takes 50-100 miles of hard driving to purge the air, and granted I haven't even gone 20, I would still like to know the "symptoms" of the process.

I checked fuel pressure under load during one of the tests. It never dropped below 65 PSI.

I recorded one of my trips, taking note of (From top to bottom) Throttle Position, Engine RPM, IPR %, ICPx2 in KPa, Manifold Absolute Pressure, and Vehicle Speed.


My biggest hiccup in the engine occurs at around 2,300 RPM. When I try to floor it from there, that's when the IPR opens up and the ICP reads a negative pressure increment. At that point, I have to put the clutch in, let off and pump the gas pedal for the engine to "catch" again. The truck has acceleration power in gears 1, 2, and 3. 4th gear does not want to increase in speed - noticeably no power. On the dash, the oil pressure stays steady, so I am assuming that my low pressure oil pump is working just fine. According to the graph above, when the pressure finally resumes, it peaks at 24,305 KPa, or 3,525 PSI; which is an improvement from after I changed out the oil seals in the pump.

The HPOP is a re-manufactured unit. And I got two codes to pop today: p1211 again and a new one p1209 (Injector Control Pressure System Fault). Upon searching these, someone brought up that these tend to come up with chipped trucks and the HPOP resivior running out of oil. One person even figured the pump was going out. Is there any belief here on that being the potential issue? I do not want to drop that much money to maybe fix my problem. I feel investing in the equipment to pressure test the HPOP would be a good next step, but if it cranks just fine, would that appear in the pressure test?

EDIT: After posting this, I poked around in the engine bay and felt the line that goes to the passenger side head quick fitting has much more movement than the line at the driver's side head (no wiggle room at all). I did not change these when I did the rings on the pump. I have ordered new o-rings for both fittings, but I currently only plan on replacing the one side for now.
 

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Discussion Starter #10 (Edited by Moderator)
I think it's fixed.... or at least I hope so.

The main source of my problem was a bad o-ring for the oil galley; the oil passage to the injectors. The plug on the passenger's side, back end of the block, is prone to failure, being right underneath the down pipe of the exhaust.



I took off the turbo and pedestal while I was doing this job. I've replaced all the other o-rings, why not these? And it made a whole bunch more space to get the ratchet back there, as well as a small sledge to give the extra umpf to break the plug loose.

I think I'm down to just burping the oil system. After a few more runs today, The truck is still kinda jerky, but I'm expecting that to be just be the air bubbles.

I'll add this in here too. I was having the wooshing sound that so many people have talked about while driving. For the back pressure exhaust solenoid. The wires on this truck needed some replacement, regarless off all the other issues. But fixing that plug fixed a huge problem I didn't know I even had. And I didn't do simple butt connects under the loom. I made sure to do this one right. Now not all my solders were this good, but this was among the best I did.
 
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