DPF delete passed Nevada smog




Nevada smog include probe and running on the rolls, but they do not plug OBD scanners.
So my car pass the sniff test, (what I did expect) with no problem. Would they plug OBD - it would show "n/a" at DPF and I guess that would be a problem in California, who do OBD check.
The test results don't show any numbers, when couple years ago they would, but what I do care? It passed period.
I would think the same for a dpf delete. Also, did you take both the cat and dpf out? They are in the same box and it's hard to just chisel out the dpf portion without dislodging the cat.




Not a big difference thought.
Now I heard that California changed the smog laws for newer cars and depends on MY they will pass even with 2 failed features.
I did last California smog a year ago and my impression that technicians have no idea what they see under MB hood did not change.
That said, NV technician open the hood as well. Same impression




- Gasoline Vehicles
- 1996-1999 Gasoline Vehicles can have 1 monitor not-ready
- 2000 and newer gas vehicles must have ALL monitors in a ready state with the exception of the EVAP monitor.
- Diesel Vehicles
- 1996-2006 Diesel Vehicles can have 1 monitor in a not ready state.
- 2007 and newer Diesel vehicles can have 2 OBD2 monitors in a not ready state




I don't think there is any equipement who can check particles. What is the car will start regeneration during the test?
Diesel tests, at least in California were triggered by pickup owners, who tuned factory 250 HP engines up to 1000 HP, obviously having no regards to emission or noise levels.
So checking EGR and mufflers on trucks is primary goal for the law.
MB diesel owners got sideswiped.
I don't think there is any equipement who can check particles. What is the car will start regeneration during the test?
Diesel tests, at least in California were triggered by pickup owners, who tuned factory 250 HP engines up to 1000 HP, obviously having no regards to emission or noise levels.
So checking EGR and mufflers on trucks is primary goal for the law.
MB diesel owners got sideswiped.
Here is a document for diesel testing in Nevada: https://dmvnv.com/pdfforms/ec4.pdf
They basically stick a opaque material in front of exhaust to see if it picks up any visible particulates.
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Washoe County is Reno, what leaves about 90% of Nevada not having smog tests (something to think about)
But now I read that the probe is opacity tester.
So either my MB is so clean that it doesn't emit particles even with DPF deleted, or the opacitor does lousy job.
I hope it stays that way, no matter what it is.

EDIT. I found smog results from year ago, when car had working DPF. Opacity number was 0.8%.
New test is not giving the number, only PASS.
Can't find much info about opacity testing, but California for heavy diesels allows 5% , what is new number for 2019
Last edited by kajtek1; Aug 16, 2019 at 07:14 PM.
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I had more time today and read the smog results again.
So there is a number of opacity with DPF delete. I did not notice it the 1st time becouse the number was 0 (ZERO).
So how the car with working DPF makes 0.8 opacity, when with DPF delete makes 0 ?
Beats me.




Each measuring equipment has its measuring tolerances, but zero is zero.




I used to drive 1980 Chevy El Camino, who never passed California smog without putting few hundred$ in it. Finally took it to state referee and got legal exception as the law can't force citizens to put big money into old car only to be pollution compliant.
Than, when the car with deleted DPF pollute less than with working DPF......


