Sit Rep: Still Stuck

[Samarath]

Codes: 343 Excessive Exhaust Back Pressure
327 Power Reduced to Match Cooling System Performance "M"

Service Performed:
-EBP sensor replacement
-EBP Tube cleaned out (with sensor removed, there's a healthy flow)
-MAP sensor replacement
-Turbo replacement with no effect. (Reinstalled the old turbo to prevent damaging the new one)
-visual inspection of harnesses for corrosion/bent pins
-ServiceMaxx J1708 - snapshots of warm-up and a short move (hopefully I did this right)
-Controlled VGT via ServiceMaxx and verified operation (Duty Cycle, Vanes open and hold as demanded)


I am conducting circuit tests today on all sensors, VGT actuator and EGR valve. I did some resistance checks before, but now I think I may have a better comprehension of the procedures and I want to record my results. I wonder if somehow a short is causing the pulsewidth signal to the VGT actuator to such a high duty cycle, but I wonder why I am not getting a code for VGT over duty cycle. If those screenshots actually post, the green dotted line that seems to be all over the graph is the Turbo Duty Cycle%. It stays frozen at 353% with intermittent drops to 30-80% for a fraction of a second.

I will try to collect more information on the electrical testing, and if anyone wants to see some specific info under certain conditions, please lmk. Thanks for your time and attention.

[Samarath]

EBP sensor
Volt KOEO
A to gnd = .07v (if voltage is present, check for short to B+ or Vref)
B to gnd = 5.07v (ok)
C to gnd = 0v (ok)

Key off battery disconnect
Connector resistance
A to gnd = .575k ohm (575ohm? Open circuit)
B to gnd = 3.3k ohm (ok)
C to gnd = 56.8k ohm (ok)

Harness resistance check (all ok)
X1-6 to A = 0ohm
X1-14 to B = 0ohm
X2-8 to C = 0ohm

MAP sensor
Volt KOEO
A to gnd = .07v (ok <.25v)
B to gnd = 0v (Vref circuit short to gnd or B+)
C to find = 5.07v (Signal gnd short to Vref or B+)

Key off battery disconnect
Connector resistance
A to gnd = .574k ohm (open circuit)
B to gnd = 57k ohm (ok)
C to gnd = 3.3k ohm (ok)

Harness resistance
X1-6 to A = 0ohm (ok)
X1-14 to B = 76.3k ohm (open Vref wire)
X2-3 to C = Open (open Signal wire)

[Samarath]

Originally Posted by Samarath

EBP sensor
Volt KOEO
A to gnd = .07v (if voltage is present, check for short to B+ or Vref)
B to gnd = 5.07v (ok)
C to gnd = 0v (ok)

Key off battery disconnect
Connector resistance
A to gnd = .575k ohm (575ohm? Open circuit)
B to gnd = 3.3k ohm (ok)
C to gnd = 56.8k ohm (ok)

Harness resistance check (all ok)
X1-6 to A = 0ohm
X1-14 to B = 0ohm
X2-8 to C = 0ohm

MAP sensor
Volt KOEO
A to gnd = .07v (ok <.25v)
B to gnd = 0v (Vref circuit short to gnd or B+)
C to find = 5.07v (Signal gnd short to Vref or B+)

Key off battery disconnect
Connector resistance
A to gnd = .574k ohm (open circuit)
B to gnd = 57k ohm (ok)
C to gnd = 3.3k ohm (ok)

Harness resistance
X1-6 to A = 0ohm (ok)
X1-14 to B = 76.3k ohm (open Vref wire)
X2-3 to C = Open (open Signal wire)

So the ECM harness to the EBP connector is good. Right? Does that mean that somewhere from the ECM x1-6 to wherever that "grounds" is my problem area for the EBP sensor? I guess the same applies to the MAP sensor since it grounds at the same x1-6 and also has an open circuit. I guess the MAP sensor also has an issue between the ECM, and B and C pins of the connector. So strip the plastic/e-tape/plastic wrap off of the wire run from the map sensor towards the ECM until I find a problem?
Is my thinking off?

[Samarath]

The continuity test to the negative battery cable should include all of the negative battery cables I guess. I will have to check again when the sun comes up. My Voltage to Ground checks should be accurate, but I will have to run the resistance checks with all Neg cables included I guess. One day someone will ask questions about a vt365 and I will have so many answers.....one day...

[Samarath]

The eges-240 that I have is from 2002. My engine has some differences such as ICP sensor location, icp connector appearance, EGR valve connector, and my MAP sensor seems to match the EBP sensor pinout instead of the diagram in my 2002 book. Any chance there is a revised edition for 04-06?

[joeblack5]

I do not know since I do not have your engine..but I like that you document your efforts. I would have thought more people adding their knowledge now that you are supplying more data.

Hope you get it resolved and that it is nothing major.. at least you got intimate with your engine and that will help you down the road.

Good luck, johan

[joeblack5]

It looks your ebp ground is compromised.. likely that wiring runs thru the valley and is hard to inspect.. can you splice it and run a wire directly to the negative battery terminal.. we have a 7.3 and the wiring in the valley is a real pain..

Good progress..
Johan

[skoontz]

I found a EGES-295-2 manual online that might be a better fit for your engine:
https://www.manualslib.com/manual/84...65.html#manual

Sorry this was meant to reply to the post above

[headdownlow0624]

Hello! After reading through this, it appears your situation can be summarized as this:
Situation #1: You have a "legitimate exhaust restriction" (Turbo vanes stuck/seized/unison ring failure, or poor VGT control due to insufficient oil pressure at the VGT solenoid), or something else downstream in the muffler or pipe (not likely).
Situation #2: No actual restriction, just "perceived", through a bad EBP sensor reading at the computer. (Not saying the computer is bad, just suggesting that the EBP sensor could be good, but with bad wiring, or good wiring with a faulty sensor, or both.)

Chaffed wiring is a red flag and must be repaired.

EBP sensors have a high failure rate - OEM parts recommended.

Your oil cooler beginning to clog (as demonstrated through your temperature difference between coolant and oil) is another red flag. A 15 degree difference in temperature is bad.

*EDIT* Sorry - just read that you already replaced some of these components. If the wiring repair doesn't remedy the situation, it may be time for a new oil cooler (and at that point, evaluating and likely replacing your IPR valve and EGR cooler). Does your motor already have a coolant filter installed?

[Samarath]

Originally Posted by skoontz

I found a EGES-295-2 manual online that might be a better fit for your engine:
https://www.manualslib.com/manual/84...65.html#manual

Sorry this was meant to reply to the post above

That is the service manual. I guess the eges-240 is the diagnostic manual. I can't seem to find a later revision of the 240. I do have the eges-295-2 which is where I found some differences while searching for the icp sensor and a revised pinpoint diagnosis for the EGR valve.

The local shop told me that we can drop the bus off, but we can't stay in the bus while they diagnose the issue. I printed some pages for the pressure sensors, temp sensors, and Vref circuit diagnosis. I am almost convinced that the turbo solenoid is shorted to B+ because it is at such a high duty cycle%353. The ecm normally sends a pulsewidth to the turbo solenoid. I wonder if a short is giving it a steady 12v resulting in the crazy high duty cycle. I almost spliced a new wire from the solenoid to the ecm, but if it was shorted like that, I don't think that I would be able to command the vgt output with service Maxx and have it respond appropriately. I got a couple of sewing needles and alligator clips for back probing harnesses and will completely check my circuits for all temp and pressure sensors. I am still at a loss on the EGR valve diagram, but I can monitor voltage via service Maxx while commanding a low output state during a continuous monitor test.

I will record all of my circuit tests, KOEO temp and psi readings and voltage, and...damn this is overwhelming. I'll post some data as I get it.

[Samarath]

Originally Posted by headdownlow0624

Hello! After reading through this, it appears your situation can be summarized as this:
Situation #1: You have a "legitimate exhaust restriction" (Turbo vanes stuck/seized/unison ring failure, or poor VGT control due to insufficient oil pressure at the VGT solenoid), or something else downstream in the muffler or pipe (not likely).
Situation #2: No actual restriction, just "perceived", through a bad EBP sensor reading at the computer. (Not saying the computer is bad, just suggesting that the EBP sensor could be good, but with bad wiring, or good wiring with a faulty sensor, or both.)

Chaffed wiring is a red flag and must be repaired.

EBP sensors have a high failure rate - OEM parts recommended.

Your oil cooler beginning to clog (as demonstrated through your temperature difference between coolant and oil) is another red flag. A 15 degree difference in temperature is bad.

*EDIT* Sorry - just read that you already replaced some of these components. If the wiring repair doesn't remedy the situation, it may be time for a new oil cooler (and at that point, evaluating and likely replacing your IPR valve and EGR cooler). Does your motor already have a coolant filter installed?

I think that the oil cooler, EGR cooler, and maybe the EGR valve all need to be replaced based on the temperature difference in oil and coolant. I am also under the impression that high EBP can cause higher cylinder temps and the oil temp can climb away. I think these are real issues, but would any of these issues cause my ecm to command my turbo to a 353% duty cycle? The way that it intermittently drops to a proper reading 25-80% seems to be a clue, but I don't know what it all means. Is the turbocharger malfunction causing the temperature difference, or the other way around. If there wasn't enough oil psi, wouldn't the turbo fall into an opened position? Anyway, knowing that the shop can't help with our current circumstances means that I don't even have the option to raise the white flag, so I will begin again with that in mind.

I am not sure about the coolant filter. It was inspected by the school district for the 2018-2019 school year. Would that have been a thing they would have done? Where would I look? Googling now...lol

[headdownlow0624]

The stock turbo on VT365s does NOT have a wastegate to regulate pressure. The moving vanes inside the turbo are the only method of controlling pressure. When the computer sees Exhaust Back Pressure(EBP) higher than target, it attempts to lower the EBP by increasing the duty cycle of the VGT actuator. This is an electrical part which contains a valve, which is actually a piston, which moves to one side when power is applied. The computer pulses a signal to the VGT actuator. This signal is ON or OFF. It switches this on-and-off very fast, a modern method called Pulse Width Modulation (PWM). If the computer is attempting 10% duty cycle, that means it's only pulsing power to it 10% of the time ("time" defined by the total cycle of the component). It will decrease duty cycle, down to 0%, to build boost while the engine is running. It will increase duty cycle to reduce/control boost. Anything over 100% just means it's attempting to keep the component activated well past it's normal cycle. Your high VGT actuator duty cycle is a direct response to your EBP sensor input. I'd almost certainly say it's a mechanical issue with your turbo. Gunk. Sludge. Stuck vanes. My friend had to disassemble and clean his turbo regularly, something like every 25k. There are some seals which are required to be replaced for this procedure, it's up on a few websites. You said you replaced the turbocharger with a new one? Was it used at all before you got it? Did it show any signs of being rebuilt?

Assuming your EBP is actually higher than spec, and that the turbocharger 100% is good, and that your VGT actuator is working properly/not sludged, than the only remaining issue would be the oil supply to the VGT actuator (and subsequently through the turbo).

[headdownlow0624]

VT365s do not come with a coolant filter. In 2007 they DID put out an "Uptime" campaign to add one, but it did not apply to VT365s produced after 1-09-06. I'm betting yours didn't get it. Mine didn't either. It's sort of a moot point since your temperatures indicate sludge in the oil cooler already. Once you change the oil cooler, you need to add a coolant filter to prevent the next one from getting clogged with crap.

[Samarath]

KOEO servicemaxx

BAP
14.6 psi
4.7 volts

EBP
0 psi (read 2376.3 for a moment)
.94 volts

MAP
0 psi
.92 volts

EOP
0 psi
.62 volts

MAT
39f
4.34 volts

IAT
41f
3.74 volts

ECT
41f
3.76 volts

EOT
41f
4.36 volts

Will follow up with each sensor. The book says that the VGT is a closed loop system with the EBP sensor, but it also seems to mention other things effecting the vgt controls. More to come.

[headdownlow0624]

Since the VGT actuator clicked in your hand, and you're sure it actually moved, then the VGT wiring probably isn't the issue. I recommend against applying voltage directly to it unless your using factory gauge wire (engine actuators and solenoids have very small windings that like to melt if you supply it with enough current, even if you're supplying appropriate voltage.)

[headdownlow0624]

Those KOEO readings look normal for a cold engine.

[Samarath]

Originally Posted by headdownlow0624

The stock turbo on VT365s does NOT have a wastegate to regulate pressure. The moving vanes inside the turbo are the only method of controlling pressure. When the computer sees Exhaust Back Pressure(EBP) higher than target, it attempts to lower the EBP by increasing the duty cycle of the VGT actuator. This is an electrical part which contains a valve, which is actually a piston, which moves to one side when power is applied. The computer pulses a signal to the VGT actuator. This signal is ON or OFF. It switches this on-and-off very fast, a modern method called Pulse Width Modulation (PWM). If the computer is attempting 10% duty cycle, that means it's only pulsing power to it 10% of the time ("time" defined by the total cycle of the component). It will decrease duty cycle, down to 0%, to build boost while the engine is running. It will increase duty cycle to reduce/control boost. Anything over 100% just means it's attempting to keep the component activated well past it's normal cycle. Your high VGT actuator duty cycle is a direct response to your EBP sensor input. I'd almost certainly say it's a mechanical issue with your turbo. Gunk. Sludge. Stuck vanes. My friend had to disassemble and clean his turbo regularly, something like every 25k. There are some seals which are required to be replaced for this procedure, it's up on a few websites. You said you replaced the turbocharger with a new one? Was it used at all before you got it? Did it show any signs of being rebuilt?

Assuming your EBP is actually higher than spec, and that the turbocharger 100% is good, and that your VGT actuator is working properly/not sludged, than the only remaining issue would be the oil supply to the VGT actuator (and subsequently through the turbo).

Initially I suspected that the turbo vanes were just stuck from buildup, but I didn't want to tear into it while on the road. I thought to save a few bucks by getting a "refurbished" turbo from eBay. I swapped it and there was no change, and so I took apart the exhaust side of my old one and cleaned it up with a DeWalt and a wire wheel and reinstalled it. I sent the ebay turbo back and bought a brand new Garrett at NAPA. There was no change in the operation of the turbo in all of these instances, and so I removed the new turbo and installed the original to prevent doing any harm to my New(now slightly used) turbo.

A low duty cycle on the turbo means it is not commanding much boost and so the vanes are relatively open and an EBP reduction results. A high duty cycle represents more demand, and so the vanes are relatively closed resulting in higher EBP, and in effect, higher boost. This is my understanding. Unplugging the turbo actuator causes the turbo to default to an "open" position and at low idle, my EBP drops from 6-7psi(plugged in) to 0.3psi(unplugged). I am not certain, but I feel like trying to get down the road with the turbo wide open causes issues with the flow of gases that are trying to be manipulated by the EGR and was placing a higher strain on everything. I unplugged the EGR valve and turbo solenoid to limp to my current location (AMC Theatres parking lot).

Certainly these events have stressed the oil cooler/EGR cooler/EGR valve, and may have roasted my sensors near the EGR. I just don't understand how these things play into the commanded duty cycle. From what I have read, the vgt control is primarily a closed loop system with the EBP sensor, but I have also read that the oil/coolant temp, and egrp sensors can effect the vgt control solenoid. I welcome all knowledge, and please correct me. I appreciate the responses to maintain my sense of hope....lol

[Samarath]

Originally Posted by Samarath

KOEO servicemaxx

BAP
14.6 psi
4.7 volts

EBP
0 psi (read 2376.3 for a moment)
.94 volts

MAP
0 psi
.92 volts

EOP
0 psi
.62 volts

MAT
39f
4.34 volts

IAT
41f
3.74 volts

ECT
41f
3.76 volts

EOT
41f
4.36 volts

Will follow up with each sensor. The book says that the VGT is a closed loop system with the EBP sensor, but it also seems to mention other things effecting the vgt controls. More to come.

Also, the vgt duty cycle KOEO is at 353% with intermittent drops to 0%

[Samarath]

Can you read this?

[headdownlow0624]

Isn't yours a 2006? That book is not accurate for 2006. Reference EGES295-2. But yes, your thumbnail posts are visible.