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+--- Thread: High exhaust back pressure (/showthread.php?tid=6332)
RE: High exhaust back pressure - Rawze - 06-28-2020
(06-27-2020 )DannyA Wrote: ... Fault code 2973. ...
2973 = imap sensor signal is intermittent.
That is more likely to be a wiring issue than anything else. Maybe your engine wiring harness grounds, alternator, etc.. has some problems of you replaced the sensor and this code came back. - would explain a lot of things including turbo and other systems acting up.
RE: High exhaust back pressure - DannyA - 07-08-2020
(06-27-2020 )DannyA Wrote:(06-26-2020 )Rawze Wrote: pull the cans, take pics of the faces and post em here,... take em to a stealers$it and have em baked, de-ashed, and flow tested.Hi Rawze,
check the decomp tube while you are at it...
http://rawze.com/forums/showthread.php?tid=283&pid=1807#pid1807
use a boroscope and check the face of the SCR element to see if it is face-plugged too.
=========
while it is apart, pressurize the whole engine up to about 30 psi and check for leaks via block plates on intake and exhaust of turbo + air supplied in where the turbo inlet temp sensor goes. fix any leaks found.
after that, do a turbo inspection if u suspect ur new turbo.
https://youtu.be/ZUpKb5umv_0
Also verify you put the right turbo part# on your engine. Seen where stealers$it or other shops use wrong model turbo on engine assuming they are all same because they look same. They look same on outside but there are different turbo's w different turbines for different tier engines and it can greatly effect regen problems. Register an account on quickserv.cummins.com with your esn number and look up the right part#. Compare it to part# on turbo and invoice.
I will take the cans out for cleaning sometime next week. I know it may sound dumb but what do you mean by pressurizing the whole engine? How I will do that?
Today anew code came on. Fault code 2973. Replaced the IMAP sensor 2 miles down the road the code came back on.
I fill like I will never be able to get this truck running. Thank you for help
Finally I got the filters down for a bake and clean. I attached pictures of the filters before cleaning. I have them back together and run a aftertreatment regeneration analysis and failed. Exhaust gas pressure to high. Exhaust gass gas pressure is around 160 during the regen, intake pressure 32 and turbo runs at 75k-77k.
It pass the filter flow test.
In NoX correction is around 165 and the out 175.
Any idea on what can cause this high exhaust pressure? Is possible to have a failed SCR and is blocking the exhaust? If the SCR is bad will not show up as some kind of NOX codes?
Anyone have an ideea?
RE: High exhaust back pressure - tree98 - 07-08-2020
There's a whole list of things Rawze gave you to do. Baking the cans was the first thing on it. You got 5 more to go.
RE: High exhaust back pressure - jimeneztrans84 - 07-08-2020
I would do egr tune up, check decomp tube where def injects to see if u have a crystalized volcano which more than likely u will. Check dpf wiring, and also some scr cans had a recall. I found out after...
RE: High exhaust back pressure - JimT - 07-09-2020
(06-26-2020 )Rawze Wrote: check the decomp tube while you are at it...
http://rawze.com/forums/showthread.php?tid=283&pid=1807#pid1807
use a boroscope and check the face of the SCR element to see if it is face-plugged too.
^^^^^^^^^^^ Do this! ^^^^^^^^^^
(07-08-2020 )DannyA Wrote: Any idea on what can cause this high exhaust pressure? Is possible to have a failed SCR and is blocking the exhaust? If the SCR is bad will not show up as some kind of NOX codes?
Anyone have an ideea?
NOx related codes are just that, NOx related. In your case something is causing an exhaust restriction. Or you have a bad sensor. Start by checking the decomp tube for a cone of DEF buildup. Then move on to the SCR can. Internally it looks just like a DPF and if particulate (including dried up DEF) works it's way in there it can clog up. Try disconnecting the exhaust pipes in different places to see if that changes the pressure readings. Start at the SCR can and work your way back until you find the source.
RE: High exhaust back pressure - DannyA - 07-09-2020
(07-09-2020 )JimT Wrote:(06-26-2020 )Rawze Wrote: check the decomp tube while you are at it...
http://rawze.com/forums/showthread.php?tid=283&pid=1807#pid1807
use a boroscope and check the face of the SCR element to see if it is face-plugged too.
^^^^^^^^^^^ Do this! ^^^^^^^^^^(07-08-2020 )DannyA Wrote: Any idea on what can cause this high exhaust pressure? Is possible to have a failed SCR and is blocking the exhaust? If the SCR is bad will not show up as some kind of NOX codes?
Anyone have an ideea?
NOx related codes are just that, NOx related. In your case something is causing an exhaust restriction. Or you have a bad sensor. Start by checking the decomp tube for a cone of DEF buildup. Then move on to the SCR can. Internally it looks just like a DPF and if particulate (including dried up DEF) works it's way in there it can clog up. Try disconnecting the exhaust pipes in different places to see if that changes the pressure readings. Start at the SCR can and work your way back until you find the source.
Rawze,
Thank you for your input so far. I didn't mention that turbocharger air cooler was pressurized and no air leak. Decomposition tube is perfectly clean and SCR looks OK. I know SCR had a recall and I replaced it 100-150k miles ago. EGR tune up was done changing the IMAP, Delta P and exhaust pressure sensor. Dealer was blaming the Turbo for all the headaches. Since we changed the turbo I'm getting the 2973 code. I only can assume this is caused by the eCM when is comparing the IMAP, turbo speed and exhaust pressure.
Rawze, any suggestions on a shop that can get me out of the hole?
RE: High exhaust back pressure - Waterloo - 07-09-2020
Mr Hag, Griffin GA... I also found this on QuickServe for the 2350... Technical Service Bulletin: TSB150071 Released Date: 20-Jan-2017
Symptom:
Fault Code(s) 2973, 122, 123, 124, or 125.
Root Cause:
New intake manifold pressure/temperature sensor, Part Number 2897333 and 2897334, were released in July 2014. The capacitor in the new intake manifold pressure/temperature sensor is not completely covered in protective silicone gel, leaving the capacitor exposed. Moisture intrusion from water spray and water/ice accumulation on the air intake manifold can cause corrosion and incorrect sensor readings.
Note : This issue does not affect obsolete intake manifold pressure/temperature sensor, Part Number 2872784 or 4921322.
Use INSITE™ electronic service tool to check for active or inactive Fault Code(s) 2973, 122, 123, 124, or 125.
If any fault codes listed above are present, remove intake manifold pressure/temperature sensor and confirm part number is 2897333 or 2897334. Part number can be found on connector.
If part number is 2897333 or 2897334, locate 16-digit serial number on intake manifold pressure/temperature sensor connector. See Figure 2 below.
For part number 2897334, if serial number is 91514383xxxxxxxx or above, published troubleshooting should be resumed. If serial number is 91514382xxxxxxxx or below, reference Resolution section below.
For part number 2897333, if serial number is 56514383xxxxxxxx or above, published troubleshooting should be resumed. If serial number is 56514382xxxxxxxx or below, reference Resolution section below.
Part number 2897334
91514383xxxxxxxx and above
OK
91514382xxxxxxxx and below
Not OK
Part number 2897333
56514383xxxxxxxx and above
OK
56514382xxxxxxxx and below
Not OK
If issue has been verified and intake manifold pressure/temperature sensor serial number range status is Not OK per Table 1, replace with part number 2897334 or 2897333, which has a serial number status that is OK per Table 1.
Note : Obsolete intake manifold pressure/temperature sensor, Part Number 2872784, can also be used to replace intake manifold pressure/temperature sensor, Part Number 2897334. Obsolete intake manifold pressure/temperature sensor, Part Number 4921322, can also be used to replace intake manifold pressure/temperature sensor, Part Number 2897333.
RE: High exhaust back pressure - DannyA - 07-09-2020
As I already said, I replaced all the sensors except one that is marked with question mark in the picture. Assuming that I'm correct with the other 2 sensors, the one will question mark will be the EGR Orifice Pressure sensor? Can that one give me a high exhaust pressure? I know that this question may sound dam for some of you but I don't know what else I can do
RE: High exhaust back pressure - Lonestar10 - 07-09-2020
When you said exh press was 160 what units was this in? Psi/kpa/inhg?
Also maybe if pressure possibly spiking was actuator installed on turbo correctly and calibrated? If the turbos arm for the vg ring wasn't in right spot or both install and installed calibrations weren't done right it can cause issues