Disabling DTCs

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Gmguy
Posts: 3
Joined: February 20th, 2025, 3:11 am

Disabling DTCs

Post by Gmguy »

Hi everyone,

I am looking at purchasing versatune for my 2007 cx7 with the 2.3t engine.

My question is regarding DTCs for EGR, if i want to disable the egr dtcs and blank the valve off am I able to do this if I purchase the lite version of the software or do I need to purchase the full version?
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Ugnius @ VersaTune
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Joined: March 19th, 2010, 11:57 am

Re: Disabling DTCs

Post by Ugnius @ VersaTune »

You can disable DTCs with VersaTuner Lite, but it is your responsibility to comply with all applicable emissions laws and regulations. Cars on public roads should only be operated with fully functioning emissions equipment to protect the environment and public health.
mituc
VersaTuner guru
Posts: 1411
Joined: December 17th, 2011, 2:47 pm
Location: Iasi/Romania

Re: Disabling DTCs

Post by mituc »

Gmguy wrote: March 4th, 2025, 6:55 am My question is regarding DTCs for EGR, if i want to disable the egr dtcs and blank the valve off am I able to do this if I purchase the lite version of the software or do I need to purchase the full version?
On a 2007 (gen1) CX7 is you block-off the EGR there's a pretty good chance the ECU will not care and you will not get a code.
However, usually blocking the EGR is not the right way. Adding catch-cans is what you may actually need if your only concern is contamination of intake and intake valves.
This is my setup:
Image

So you can see both catchcans here. My both cars pass emissions as measured (they may fail visual, but measured they pass even stricter norms). So it's possible to have no need to disable any emissions related code and also have more power.
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~550BHP @35PSI
2008 Icy Blue Mazda CX7
Built engine and stock exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 360-ish BHP
Gmguy
Posts: 3
Joined: February 20th, 2025, 3:11 am

Re: Disabling DTCs

Post by Gmguy »

mituc wrote: March 5th, 2025, 3:25 pm
Gmguy wrote: March 4th, 2025, 6:55 am My question is regarding DTCs for EGR, if i want to disable the egr dtcs and blank the valve off am I able to do this if I purchase the lite version of the software or do I need to purchase the full version?
On a 2007 (gen1) CX7 is you block-off the EGR there's a pretty good chance the ECU will not care and you will not get a code.
However, usually blocking the EGR is not the right way. Adding catch-cans is what you may actually need if your only concern is contamination of intake and intake valves.
This is my setup:
Image

So you can see both catchcans here. My both cars pass emissions as measured (they may fail visual, but measured they pass even stricter norms). So it's possible to have no need to disable any emissions related code and also have more power.
I would normally use WinOLS and zero out the egr control tables as well as remove the dtcs for a complete solution, however I have been unable to find any mappacks for this operating system.

A little bit of oil contamination in the intake is of no concern to me really as the pcv system is working as it is designed, my issue is with a direct injection engine and egr, without the presence of fuel to keep things clean it is just asking for trouble.
Gmguy
Posts: 3
Joined: February 20th, 2025, 3:11 am

Re: Disabling DTCs

Post by Gmguy »

mituc wrote: March 5th, 2025, 3:25 pm
Gmguy wrote: March 4th, 2025, 6:55 am My question is regarding DTCs for EGR, if i want to disable the egr dtcs and blank the valve off am I able to do this if I purchase the lite version of the software or do I need to purchase the full version?
On a 2007 (gen1) CX7 is you block-off the EGR there's a pretty good chance the ECU will not care and you will not get a code.
However, usually blocking the EGR is not the right way. Adding catch-cans is what you may actually need if your only concern is contamination of intake and intake valves.
This is my setup:
Image

So you can see both catchcans here. My both cars pass emissions as measured (they may fail visual, but measured they pass even stricter norms). So it's possible to have no need to disable any emissions related code and also have more power.
Also just out of curiosity why have you fitted a catch can on the fresh air inlet? That hose from the air intake pipe to the rocker cover is supplying clean air to the engine crankcase to offset the vac pressure that pcv system applies so there is no need for a catch can on that side of the engine
mituc
VersaTuner guru
Posts: 1411
Joined: December 17th, 2011, 2:47 pm
Location: Iasi/Romania

Re: Disabling DTCs

Post by mituc »

Gmguy wrote: March 8th, 2025, 6:54 am Also just out of curiosity why have you fitted a catch can on the fresh air inlet? That hose from the air intake pipe to the rocker cover is supplying clean air to the engine crankcase to offset the vac pressure that pcv system applies so there is no need for a catch can on that side of the engine
This is not entirely correct. During boost at least, the flow is from the valve cover to the intake almost all the time.
The PCV valve side of the crankcase ventilation works during vacuum, when the absolute pressure in the intake manifold is lower than the crankcase pressure, and that's when the valvecover breather may supply a bit of air to replace the volume sucked in through the PCV.
Then the valvecover breather line works pretty much all the time the turbo puts on some work, because it will create vacuum in the intake (before the turbo) which will invert the flow and vent the crankcase through the VC breather line.
The lower (oil pan/the back of the PCV case) and upper crankcase (valve cover) basically share the same volume, so BOTH vent the crankcase but in different conditions, and only in very specific conditions (low turbo DC and high IM vacuum) the valvecover breather line will have inverted flow.

That is why you need catchcans on both lines. And this setup is pretty efficient as well, condensing down those vapors will simply lower the quantity of potential expanding cases in the crankcase (that is the only way a catchcan will lower the crankcase pressure unless you drill additional vents, which I do not think you need unless you're making a huge amount of power, like 600-700+).
2008 Cosmic Blue Mazda 3MPS
Built engine + WMI + GTX3071 gen2, ~550BHP @35PSI
2008 Icy Blue Mazda CX7
Built engine and stock exhaust (YES!!), JBR3" + GTX2867 gen2 + Autotech HPFP, self-tuned to 360-ish BHP
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