Hey all. Quite awhile since I've visited, but I have a dilemma that has me stumped.

Quick history.
I had a pedestal leak and decided to replace the EBPV with a non EBPV pedestal. While I was in there I rebuilt the turbo, added a WW2. Bellowed up- pipes. New manifolds. AFE wastegate. Riffraff crossover line and CVDs.

Got everything together and found out the hard way there was a small threaded hole in the non EBPV pedestal that wasn't plugged and wound up puking about 1.5 gallons of oil in the driveway. The 7.3 wasnt thrilled about that and celebrated with coughing, bucking, e.t.c, e.t.c.
Long story short, I had her shut down within seconds after realizing what was happening. Tore it back down, fixed the issue and got her back together.

Prior to this, it ran fine. Not even a hiccup. The only issue I found was when it was cold out it was sluggish. I figured maybe the EBPV was a little sticky. Once warmed up, she was fine.

Now it's back together. Fires up, idles mint, but at about 1100-1700 rpms there's a shutter. Seems like a miss.

I downloaded a program for android, "car gauge pro" and via bluetooth you can buzz test and run a cylinder contribution test. I have torque pro, but that wasn't cutting it.
Fast forward. The truck on the contribution test flags PO269 and PO284. Cylinder 4 and 8 for contribution/ balance. On the buzz test, I get a good buzz on all 8.

Oil is fresh rotella after I did the work. Year old motorcraft CPS. Year old ICP. Both unplugged give a bad result.
Year old Bosch pump. Broken pickup tube, but I have 3/4 tank.
Fresh filter in the bowl.
3 year old motorcraft glow plugs.
Recent batteries with no alternating/ fluctuating sounds/ rotations of the motor.

I've checked all the wiring from the IDM all the way up the the connector at the valve cover and I can find nothing loose, or any abrasions. Pulled the valve cover today to check on the gasket and all connections seem mint. I pulled the 4 injector today hoping to find something but came up empty other than finding a broken zip tie that broke inside from the wiring. I recovered that and reassembled. Started it back up and pulled the connectors at each injector which revealed each injector was providing fuel through hearing the rpms drop.

At idle it runs excellent. Above 1700 it seems fine. The only thing I haven't really tackled is the FPR at the bowl.

There arent any any other codes other than EBP. I replaced the tube, but apparently the sensor is bad.

Per CGPro, my injector pressure is at 608psi (idle).
Duty cycle (if that matters), 24.9.
On any, "misfire" test, I get a, "no" misfire from the software.
No smoke on startup other than what I would consider normal for a cold truck. 30-ish degrees. Any smoke mostly clears after 15-20 seconds.

I have another injector on the way, as well as a new VC gasket, however after taking that apart, I was surprised at how everything looked.

If anyone has any ideas, I'd appreciate it. Im running out of options other than replacing the IDM and FPR.

 

what is the code you referred to as EGR? There is no EGR on a 7.3 and it sounds like you're referring to the exhaust back pressure sensor. How do you know it's bad?

It sounds like it could be a valve cover gasket wiring issue.

 

Correct. My apologies. It's EBP.
Code is PO470. I'm only assuming it's bad based on the code. The tube is new.
I've checked the gasket wiring and it seems fine. Nothing discolored or melted. Visually I can't find anything wrong with it. On a glow plug test it comes back ok. Buzz test works on all 8 injectors and unplugging them one by one reveals they are firing.
- shrugs shoulders -

 

https://www.ford-trucks.com/forums/5...-no-power.html

Let us know how it works after changing the EBP sensor. If it fixes it, forget about the gasket and injector.

 

Fixed my PO470. That sensor and tube where the sensor mounts was bound up good with sludge/ rust/soot.

Got everything back together today. I went as far as replacing my number 4 injector.

The miss is still there. The truck is throwing P1278 and P1274. It's also taking a few seconds longer to start than usual.

So, with that said, Cylinder 4 and 8 "high to low side open" is what she's complaining about now!

This comes up when I do a buzz test. Everything I've read says the 8 is pretty common after replacing the cam sensor. My suspicion is that 4 isn't performing and it feels like Im missing a cylinder. However, I can hear it buzz on the test. I've unplugged it while running and I can also hear it drop out. Harness and connectors on the valve cover, both inside and out look good. I can't find a hint of anything peculiar. I have another gasket I bought a few days but opted not to install it given the condition of the OEM harness. I guess I should probe wires from the harness to the idm.
Is it possible to pass the buzz test, but still lose the cylinder?
I would think if it passes the buzz test, and can verify hearing the cylinder drop out when I disconnect the injector, it would be ok?
No... yeah...? I'm not certain I understand the injector having what seems like an open circuit. Seems like either it has a connection, or it doesn't.

 

When my #2 went out earlier this year the engine ran like trash and i got the code for that injector circuit open. I ran the buzz test and I heard all 8 buzz, but the #2 and a couple others in the bank weren't as loud as the rest. What do yours sound like? They all need to buzz LOUD and HARD if any of them sound a little muffled that could be the problem. My #2 sounded like it was under a big blanket. I replaced my UVCH and that solved my issue. My connector under the valve cover had failed and the pins had poor contact and high resistance.

 

They all seem pretty crisp, and strong. I'll tear into it again tomorrow. Im getting good at taking it apart at this point. Lol.
I have another harness. Im going to install it and be done on that end of things. I'll ohm out my wires too.
After that, I'm going to consider another IDM.

 

Update to anyone following.

I probed the injectors through the harness. I got various readings. Some under 5 ohms, some over.
I have another VC gasket I bought just in case, so I pulled the VC again to replace it. While I was in there I probed the injectors individually and all read 2.7 - 2.8 ohms at the injectors themselves. I probed through the oem harness while it was out and got various readings to all the pigtails that would connect to the injectors and glow plugs. They didn't just, "zero" out. Visually, I see nothing wrong with it. The under cover plug/ junction had some oil in it. Maybe that amounts for something?
Anywho, I got it back together. Same symptoms. I would like to mention when the truck is running at idle with the VC offer, the oil coming through the head to feed the valvetrain seemed slightly aerated. Very, very fine bubbles almost giving a gravy appearance. I never noticed that before. Fyi, there's roughly 10 miles on this rotella.

Just for the hell of it, I ran another cylinder contribution test.
PO269/PO284. Both 4 and 8 again.

Did a buzz test as well. Up until this point I never had a problem doing this, however on one test it will buzz all 8 and then fail to complete the test. If I clear it, reset and try again, it won't buzz. The software keeps trying, but throwing, "unknown code" prompts.
Try again, it may buzz, but won't complete. Try again and it throws, "unknowns".

Where im at?
The injectors ("appear") ok, at least according to an ohm test. The VC gasket is new. Exterior harness that plugs into the VC gasket is passing a visual. Since I did manifolds I still have the drivers fender well out. I decided to look over the IDM. Connection was good, but the case is severely oxidized and there's a plug that wasn't seated any longer in the case leaving it exposed to moisture.

Im wondering if the IDM is having some issue considering I can't get it to complete a buzz test and its throwing, "unknowns" according to software. For 200 on Ebay I can get a refurb, so I think im going to try that. In my mind, that leaves wiring to dig through. So far though, any areas you would think you'd have issues, seem clear of any. It would only leave a break in the middle of the harness somewhere which would seem unusual to me. Especially when all the junction and, "rub" points seem fine.

 

New IDM. No difference. The last IDM was in rough shape so I don't doubt it wasnt too long for this world.
Anyhow, I pulled both VCs today. Verified oil was exhausting from each injector. Physically pulled each injector plug and and verified the engine stumbled on each cylinder.

Im questioning if they might be compromised with debris somehow. First thing this AM I shot my manifold with a laser thermometer and found all different readings. Even setting my idle at 1250 rpms I didn't get much over 200 degrees on only 3 cylinders.

I've also noticed what seems to be excessive, raw oil coming out of my top driver's side IC pipe. Im due for new boots, but I didn't have this before the work. Fast forward and i found my turbo pedestal is also leaking at the mount between the pedestal and the turbo. I tore into that as well and it seems that on the larger Oring (which is new motorcraft parts) was leaking toward the back. The groove the oring sits in, looking down on it, it appears the groove is deeper from 10 o'clock to 1 o'clock. Thus, the new oring doesn't sit up enough to seal. I don't know if this has any relation to how the truck is running, but it certainly, imo, could contribute to some loss of pressure or aeration of oil. Maybe, maybe not??

So far, I'm back to the truck being torn down to where it was a month ago. I'll pull the turbo apart tonight and see if anything stands out. The housing where the exhaust and center section meet has a damp oil appearance all the way around. I dont know if its leaking in that area, or if its oil that's worked it's way around that seam from the pedestal leaking.

Just putting this out there for a record in case it helps someone else. If it continues after reassembly, I'll have to wave the white flag and pay someone to figure this out. I'd love to solve it on my own though. Lol