Unplugging egt sensor fixes low power issue. But why?

Thanks to all who make these forums great.
2013 VNL 430 D13- 600K
Truck boost builds to usually 10-12 psi (but can vary 8-20 psi) then stops and engine shutters. So the problem is more pronounced when loaded and on hills where boost is required. This always happens between 1400-1600 rpms. fuel pressure always 60psi plus, Turbo speed maxes at 90,000 rpms. Seems to also be temperature related. The first minute it runs fine.
If I unplug the egt sensor on the cross over tube, the problem is gone. The truck runs great unplugged.
Codes are SPN 1127 FMI 10,14,18. All turbo related.

New-Batteries, Batt cut-off switch, Engine wiring harness, Delta P sensor, MAP sensor (4 times), egt temp sensor, CAC boots, Turbo, fuel filters, oil filter, coolant tank, new dpf gaskets on install, overhead completed,

Cleaned-DPF, DOC, egr, egr cooler,

Tested-turbo before replacement 4 times, EGR was replaced with a new one and problem still there, relative cylinder compression, fuel pressure, clear tube test, ECM swapped at Volvo and tested (old ECM re-installed), DPF after cleaning, boost test to 25psi (tiny leak in CAC), blow by passed

Programmed- turbo actuator twice from Volvo and another shop.

Like I said it runs great if egt sensor is unplugged. My next guess is the egr oil lines. Particularly the return line. Does anyone have experience that can point me in the right direction?

 

Thanks for your reply. Your response got me thinking. If the truck is not heating up then maybe it is the egt sensor. After the truck spent an additional 20 hours at Volvo getting diagnosed, I did not consider that the egt sensor after the exhaust side of the turbo may be the culprit. This truck does not have a dash egt gauge. It may be in the digital options.

I will confirm my oil temp and egts tomorrow.
Coolant 175 degrees running flat ground at 70mph load with 72K, 1600 rpm. On hills coolant goes up to 195. Fan kicks on and holds it there. 80 degree outside temp.

The truck will exhibit the problem bobtailing around the block.

For the threads information the old crossover temp sensor’s ohms were 220. The new Volvo sensor was 230. No change in truck performance so I think this is a good value if trouble shooting.

 

Temp ambient—85
Gross weight—73K
Oil temp warm idle—205
Oil temp flat is—
Oil temp hill—240-245

Coolant warm idle—168
Coolant flat—175
Coolant on hill—195

Oil pressure warm idle—17-37psi why does this change?
Oil pressure flat—60psi
Oil pressure on hills—60psi

EGTs idle—290
EGTs hill—750


After searching oil temps on the D13 on the forum it looks like 240 is normal. Post title is “2014 D13 Oil Temp”
My oil temp looks normal.

I also checked the egr valve outlet orifice and there is a screen that would prevent any chunks from the inlet line or parts of the egr valve breaking down and flowing back to the engine.

 

Any additional information or interpretation of these numbers or this problem would be appreciated. Thanks

 

Wait. I have one more thing to check from your suggestion. I’ll post back tomorrow.

 

Didn’t change. Plugged in or unplugged the numbers are the same. So, I still need help on this one.

 

I have cleaned the air side of the egr cooler. Is there a screen on the coolant side of the egr cooler that can get blocked? Does the coolant part of cooler get plugged? I will take a temp reading when, the truck is hot, of the inlet and outlet air tubes of the cooler. I’ll use a IR temp gun. Does anyone have the inlet and outlet temps of the coolant and air for this heat exchanger? Or the delta T?