Exhaust Back Pressure at Idle . Turbo boost spiking

Brandon0928 · Nov 28, 2022

TruckerPete1990 said: ↑

Looks good I would just run it. These emissions engines do weird things at weird times. Unless you log it while it's doing one of those weird things it's a guessing game.
Click to expand...

I thought I did log it while it was doing it but seems like I can only see the info from when I first connect to when I disconnect. Nothing inbetween

DG Laron · Jul 15, 2024

Brandon0928 said: ↑

X15 CM2350 X114B
Having exhaust back pressure at idle. Doesn’t matter if engines cold or hot. At 700 rpm it’s not very noticeable but you can hear the turbo boost intermittently. At 800 rpm boost goes up to 10. At 950 goes up to 20. When idle reaches 1000 it goes away. Seems as there is a rattle in the valve train (been the way since I bought the truck)

Engine has 660,000 miles. Rebuild at 590,000. Bought it at 640,000. New emissions during overhaul.
I just got insite and have done the rail leak test. 288 drop in 60 seconds. Did the cylinder cut out test and it passed. Just now did a forced regen to make sure it would complete one. Completed regen in about an hour. I have geo tab and it has been showing a constant active regen.
Insite shows no fault codes.
Parts I’ve replaced
Inlet Nox Sensor 11-16-22 due to code 3725
Air filter
Crankcase pressure sensor
Egr Differential Pressure sensor
Dpf differential pressure sensor
Exhaust gas pressure sensor
Intake manifold air pressure sensor

- from egr cooler inlet to the intake I took off all pipes and cleaned them with carb cleaner. I replaced the egr cooler inlet gasket, and all o rings and seals to the intake. Replaced all CAC hoses and clamps.

Exhaust outlet pipe replaced with Part # 5579020 when I first got the truck. 644233
Bellow pipe was replaced as it was leaking and sending smoke into the cab at 655,616

RIGHT NOW.
— after regen truck is idling on its own at 800rpm. Usually always idles on its own at 700. I always bump it up. So with the truck idling by itself at 800 I’m not getting the exhaust back pressure with turbo boost spiking. Bump it up to 900 and still doesn’t do it. No change at 1000rmp. Usually when it idles at 700rpm and I bump the cruise up 1 notch it goes up to 800. Now with it idling at 800, I bump it up 1 notch it only goes to 830.

What do I do next ? Is there a way I can send info from insite to someone to look it over to see if something’s out of line? Appreciate all the help I can get.

-This all started after I got the 3725 code-
I did send in an oil sample and it came back good

Shut the truck off for 30 minutes. Turned it back on. Idle at 700 like normal. Bump cruise up to 800. Turbo isn’t boosting. Let it run for a little bit and get back in the truck and idle is back up to 800. Turbo wasn’t boosting but sounded like maybe it was just a tiny bit.

posted on rawze earlier. just looking for all opinions and if someone had something similar happen to them and what the fix was
Click to expand...

DG Laron · Jul 15, 2024

Did you ever find out what the problem was?
I’m having the same issues with my Pete.

DG Laron · Jul 15, 2024

Brandon0928 said: ↑

X15 CM2350 X114B
Having exhaust back pressure at idle. Doesn’t matter if engines cold or hot. At 700 rpm it’s not very noticeable but you can hear the turbo boost intermittently. At 800 rpm boost goes up to 10. At 950 goes up to 20. When idle reaches 1000 it goes away. Seems as there is a rattle in the valve train (been the way since I bought the truck)

Engine has 660,000 miles. Rebuild at 590,000. Bought it at 640,000. New emissions during overhaul.
I just got insite and have done the rail leak test. 288 drop in 60 seconds. Did the cylinder cut out test and it passed. Just now did a forced regen to make sure it would complete one. Completed regen in about an hour. I have geo tab and it has been showing a constant active regen.
Insite shows no fault codes.
Parts I’ve replaced
Inlet Nox Sensor 11-16-22 due to code 3725
Air filter
Crankcase pressure sensor
Egr Differential Pressure sensor
Dpf differential pressure sensor
Exhaust gas pressure sensor
Intake manifold air pressure sensor

- from egr cooler inlet to the intake I took off all pipes and cleaned them with carb cleaner. I replaced the egr cooler inlet gasket, and all o rings and seals to the intake. Replaced all CAC hoses and clamps.

Exhaust outlet pipe replaced with Part # 5579020 when I first got the truck. 644233
Bellow pipe was replaced as it was leaking and sending smoke into the cab at 655,616

RIGHT NOW.
— after regen truck is idling on its own at 800rpm. Usually always idles on its own at 700. I always bump it up. So with the truck idling by itself at 800 I’m not getting the exhaust back pressure with turbo boost spiking. Bump it up to 900 and still doesn’t do it. No change at 1000rmp. Usually when it idles at 700rpm and I bump the cruise up 1 notch it goes up to 800. Now with it idling at 800, I bump it up 1 notch it only goes to 830.

What do I do next ? Is there a way I can send info from insite to someone to look it over to see if something’s out of line? Appreciate all the help I can get.

-This all started after I got the 3725 code-
I did send in an oil sample and it came back good

Shut the truck off for 30 minutes. Turned it back on. Idle at 700 like normal. Bump cruise up to 800. Turbo isn’t boosting. Let it run for a little bit and get back in the truck and idle is back up to 800. Turbo wasn’t boosting but sounded like maybe it was just a tiny bit.

posted on rawze earlier. just looking for all opinions and if someone had something similar happen to them and what the fix was
Click to expand...

Did you ever get to the bottom of this issue. I’m having the same problem with my Pete now.

Diesel Dave · Jul 16, 2024

DG Laron said: ↑

Did you ever get to the bottom of this issue. I’m having the same problem with my Pete now.
Click to expand...

Is that your “Cane Corso” in your avatar?

DG Laron · Jul 18, 2024

Diesel Dave said: ↑

Is that your “Cane Corso” in your avatar?
Click to expand...

yes it is !!

Diesel Dave · Jul 20, 2024

Here’s mine.

DG Laron · Jul 22, 2024

Diesel Dave said: ↑

Here’s mine. View attachment 522222
Click to expand...

Beautiful Pup!!!

sirrepairsalot · Jul 23, 2024

I had a 2012 Freightliner Coronado give me grief one time. The Emissions system kept trying to regen the system and failing each time giving the ECM a failure "status". DPF was plugged and replaced (not saying yours is), but with the Inlet Sensor issue the emissions system may need to be reset in Insite saying to go ahead and consider it serviced and put it back into active mode for Regens during normal operation. It is under a procedure tab of some sort, you basically go in and reset DPF Service.

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