Just got SPN 4364 FMI 18 code

it will take 2-4 weeks to get fleet id. $500 plus sales tax for 1 year.

 

Nope, got the low NOx code again for about 30 seconds. And it was a Monday morning again.
I have my scan gauge set to read inlet and outlet NOx ppm sensors.
The inlet read 280 - 600 ppm under load while the outlet read 150 - 280 under load, less than 10 while cruising.

 

inlet value is normal. outlet value is very little high.

 

Saw outlet around 150-165 today. Seems to change with atmospheric conditions.

 

possible. I have seen increased values of outlet nox in Flagstaff, AZ area .

 

Just noticed today that when I’m using my full jake brake, my secondary air pressure drops right in step with the jake.
Do I have a leak on the turbo actuator/ wastegate ?
If so, could this be the cause of the NOx issue?

 

your air pressure gauge is electronic or mechanical? even if you have a leak I don't think it will cause nox conversion issue. did you install def awning?

 

Yes I had the DEF awning installed. Didn't make a difference.
I saw tonight that the air leak gets progressively worse depending on the strength of the jake brake setting. But never does it under power, even full boost. Probably the wastegate. Just a coincidence.

 

@mhyn
Finally seem to have solved my Low NOx Efficiency code popping up every Monday.
Back in November I heard a rattling noise under the hood which went away in short order. Later I discovered one of the exhaust manifold bolts, number 4 cylinder, was missing. Hense the rattle noise when it was on it's way out. Saw evidence of a gasket failure, there was soot around the number four manifold port.
That was the second exhaust bolt to have fallen out. A year before one from the number three cyclinder had also fallen out. But there was no soot, so we thought it was fine.
All this time I had exhaust leaks, which screws up the EGR system and soot control.
Freightliner replaced all the exhaust manifold gaskets with new improved design under warranty.
The first week after this, I saw the low NOx code twice, probably cleaning itself out. Never seen it since then.
Now I seen outlet NOx under 50ppm most of the time, even under 10ppm. Instead of over 150ppm.

 

@uncleal13 thank you for sharing it . I have never seen exhaust bolts come out itself on pre EPA17 engines...