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Discussion Starter · #1 ·
Not an original idea I know and with information from others on the board I decided to try it. 2017 Colorado, no tune, stock except for an oil separator.

I disconnected the line from the oil separator going to EGT cooler/intake hose. I used an AN 10 cap and screwed it into the line going to the intake to plug it off. I just left the outbound side of the oil separator to vent to atmosphere under the hood (for now). I believe I remember someone saying that if you left the hose going to the cooler/intake open to atmosphere the truck will set a code, so I capped it off. I’m not sure why this would be other than you are allowing unfiltered air into the turbo inlet, don’t know why it would set a code. Not conclusive but I took the truck on a 30 minute drive both around town and for about 10 minutes of highway at 75. No codes were set. Not sure if I’ll eventually set a code or not. I will need to route a hose from the oil separator down to the frame as I don’t want soot being sprayed all over the engine bay. I did like the fact that when I lifted the hood that it slightly smelled like a diesel, very faint.

Pro’s:
No soot or oil getting to intake.
Cleaner oil
Probably a little better response since there is no exhaust going into the combustion chamber.
Possibly a little better power? I don’t know if under heavy load the ECU shuts the EGR. If it does then it’ll have no effect at WOT.
Maybe better fuel economy? Questionable at best.

Con’s:
Might set a code, time will tell. Limp mode?
Slight diesel smell (I liked it personally)
Could cause more frequent regens? I’d have to think this one thru more as I don’t know why burning soot in the combustion chamber vs. venting it to atmosphere would cause more regens.
 

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Not able to follow what you did.
But
if you disconnected the hose going from the crank case vent to the turbo intake.
Then blocked the turbo end and left the hose hang down to vent.
ok that’s good.
I did that to but added on to the hose and ran it inside the frame .
The smell was to strong in the cab.

If this is what you did you will not have cleaner oil.
This will not stop soot from getting to the EGR and then into the engine.

What it will do is stop the oil mist from mixing with the exhaust soot in the EGR .
When oil mist from the crank case mixes with the soot it plugs up the EGR.
Oil and soot turns to a nasty goo.

If you disconnect anything going to the EGR it will throw a code.
The only way to stop soot from being dumped into the engine is to get the ECU reprogrammed and then delete the EGR or block off the pipe from the exhaust....
The computer even monitors exhaust temperatures and will know if exhaust isn’t getting to the EGR.

Rob
 

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Discussion Starter · #3 ·
Sorry, let me re-explain. I had previously installed an ADP oil separator. As instructed, I disconnected the molded hose that goes from what I assume is the EGR on top of the engine (towards the back). That molded hose I plugged into the out-bound side of the oil separator. I then took the supplied 5/8" heater hose and plugged one end into the input side of the separator and then other end of the hose into what I believe is the EGR on top of the engine.

what I did last night was disconnect the molded hose that came from the outbound side of the separator and plugged it. The other end of that hose goes to the turbo intake hose. When running I can feel pressure puffing out of the oil separator. Once warmed up the puffing is hot.

Maybe I'm work and this isn't the EGR? I had just assume it was, maybe it's the diesel version of a PCV? What's that called CCV or something like that? If it is, where's the EGR and can you just unplug the hose?
 

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Sorry, let me re-explain. I had previously installed an ADP oil separator. As instructed, I disconnected the molded hose that goes from what I assume is the EGR on top of the engine (towards the back). That molded hose I plugged into the out-bound side of the oil separator. I then took the supplied 5/8" heater hose and plugged one end into the input side of the separator and then other end of the hose into what I believe is the EGR on top of the engine.

what I did last night was disconnect the molded hose that came from the outbound side of the separator and plugged it. The other end of that hose goes to the turbo intake hose. When running I can feel pressure puffing out of the oil separator. Once warmed up the puffing is hot.

Maybe I'm work and this isn't the EGR? I had just assume it was, maybe it's the diesel version of a PCV? What's that called CCV or something like that? If it is, where's the EGR and can you just unplug the hose?
EGR Is on the right side of the engine if looking at it from the front. Turbo and what you're messing with (I believe) is on the left side of the engine. EGR is a long, rectangular-ish silver deal.
 

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Discussion Starter · #5 ·
Yes, what I'm talking about when looking from the front is on the left rear of the engine. Where does the EGR exhaust gasses enter the intake track? Is it internal to the head or intake manifold the way older gas engines did or does it route somewhere via a hose or duct? If internal then not sure how to vent it to atmosphere. I had wrongly assumed that the the thing on the rear left of the engine was an EGR but maybe it's a crank case vent.
 

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Discussion Starter · #7 ·
Did a little checking. Anyone tried this? Basically making a block-off plate to sandwich between the tube and the valve so exhaust gasses can't enter the intake. Assumption is it would add soot load to the DPF since some soot isn't being re-burned but you would not get added soot to the oil or the intake track.

 

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We have a complex computer driven system of checks and balances. If EGR was physically blocked off as shown in the video, NOx production would rise, and the ECM would detect that via the NOx sensor in the exhaust and spray more DEF to compensate. The system already does this when the truck is in DPF regeneration mode - EGR is turned off during regens to get exhaust gas temps higher to assist with cleaning the DPF.

Assuming it does not throw a code, DEF usage would go through the roof with the EGR physically blocked off. Also, the SCR (selective catalyst reduction) in the after treatment system where NOx is addressed might not like that much DEF being sprayed into it all the time.

Really the only way to do what you want to do with EGR is to have the ECM flashed with an emissions intact tune (which turns off EGR all the time like the truck is in permanent regen mode, plus programming to either turn off or address DEF usage) or a full delete tune with physical removal of the after treatment system.

New EPA legal emissions compliant tunes are now just hitting the market. I am interested in hearing about how they address EGR and stay compliant with EPA regs. I have to imagine they are still running EGR. Perhaps a little less EGR and more DEF? I dunno. If in the market for an EPA legal tune, I would be willing to have to add more DEF to reduce EGR usage, within reason and the SCR's ability to handle it.
 

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Discussion Starter · #9 ·
I do agree, there is no silver bullet. Turning off the EGR probably adds soot load on the SCR system and DEF injection volume. Same as a block off I'd imagine. You could probably get more complex and block off EGR intake port and then vent the exhaust to atmosphere. Yes you'd add smell to your truck from the vented untreated EGR exhaust but you are probably reducing soot load as some soot is being vented. Might even reduce DEF injection and slightly longer times between regens. All theory of course.
 

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I do agree, there is no silver bullet. Turning off the EGR probably adds soot load on the SCR system and DEF injection volume. Same as a block off I'd imagine. You could probably get more complex and block off EGR intake port and then vent the exhaust to atmosphere. Yes you'd add smell to your truck from the vented untreated EGR exhaust but you are probably reducing soot load as some soot is being vented. Might even reduce DEF injection and slightly longer times between regens. All theory of course.
Be very careful messing with this system. If you block off the CCV it will do major engine damage. If you block off the steel pipe to the EGR it will throw a code and probably go into limp mode.
Like Dukem4evr said it’s a complex system.
And it is very unforgiving to experimentation.
There is no simple solutions.
You need reprogramming to make any progressive changes to the system.
I just don’t want to see you damage a very expensive engine.

Rob
 

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Discussion Starter · #11 ·
No, I didn't block off the CCV, I plugged up the hose to the intake that the CCV feeds. The CCV was going thru my oil separator and then venting to atmosphere. I'm certainly not at a point to try and vent the EGR to atmosphere as that would take a little engineering that I quite frankly don't have the time or drive to do. I don't know how much actual exhaust by percentage is fed from the EGR to the intake as a percentage of exhaust volume. That percentage assuming it didn't throw a code could probably be the increase in soot load and regen cycles if blocked off. Doing a block off is probably the easiest and cheapest to try and to put back if a code is set.

I'm not sure how to "reset limp mode". I've read of people resetting limp mode but I don't know how it's done. Is it as simple as clearing codes with OBD Fusion or is it a trip to the dealer?
 

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Turning off egr will give you higher combustion temps which should actually reduced the load on the dpf since the fuel is burned more completely. The nox production though would go through the roof though, and not just a little bit but a lot. In a write up from John Deere on developing their newer emissions compliant diesels they claim that with egr the def usage is 1-3% of fuel usage to hit emissions compliance while without egr the def usage was 6-9% of fuel consumption. So imagine a 4x increase in def usage without egr in order to hit emissions compliance. John Deere Tier 4 Final engines using EGR and SCR. . With just a 5.5gal def tank it'd only lasts you a handful of tanks before needing filled.
 

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Discussion Starter · #13 ·
That's an interesting article, thanks for the info. Seems the only way around it would be to vent it but that's more of a job since you'd need to run a small exhaust pipe under the truck to keep fumes away. Thanks again for he interesting read!
 

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Not an original idea I know and with information from others on the board I decided to try it. 2017 Colorado, no tune, stock except for an oil separator.

I disconnected the line from the oil separator going to EGT cooler/intake hose. I used an AN 10 cap and screwed it into the line going to the intake to plug it off. I just left the outbound side of the oil separator to vent to atmosphere under the hood (for now). I believe I remember someone saying that if you left the hose going to the cooler/intake open to atmosphere the truck will set a code, so I capped it off. I’m not sure why this would be other than you are allowing unfiltered air into the turbo inlet, don’t know why it would set a code. Not conclusive but I took the truck on a 30 minute drive both around town and for about 10 minutes of highway at 75. No codes were set. Not sure if I’ll eventually set a code or not. I will need to route a hose from the oil separator down to the frame as I don’t want soot being sprayed all over the engine bay. I did like the fact that when I lifted the hood that it slightly smelled like a diesel, very faint.

Pro’s:
No soot or oil getting to intake.
Cleaner oil
Probably a little better response since there is no exhaust going into the combustion chamber.
Possibly a little better power? I don’t know if under heavy load the ECU shuts the EGR. If it does then it’ll have no effect at WOT.
Maybe better fuel economy? Questionable at best.

Con’s:
Might set a code, time will tell. Limp mode?
Slight diesel smell (I liked it personally)
Could cause more frequent regens? I’d have to think this one thru more as I don’t know why burning soot in the combustion chamber vs. venting it to atmosphere would cause more regens.
I did the same thing on my Toyota Hilux. The issue is the system is engineered to have the intake suck the blowby out of the crankcase. Just venting into the atmosphere does not vent the pressure enough which causes stress on the piston rings and will cause additional blowby which causes a snowball effect. My Hilux only has 40,000 miles and was using oil due to the blowby. After reconnecting the vent tube to the intake it stopped using oil. The better option is to leave the crankcase blowby breather connected and delete- block the EGR. The crankcase blowby will not build up on the intake with the EGR blocked off. However with the EGR on the extreme heat cooks the crankcase blowby oil which bakes it onto the egr valve and intake. My truck was having issues not running correctly, using oil, limp mode and had heavy blowby with the crankcase venting to the atmosphere. A test, take the oil cap off the valve cover with the engine running and put your hand over it to feel the amount of blowby pressure in the valve cover. Reconnect the crankcase vent breather to the intake and then check it again. My toyota Hilux diesel has a major notable difference in less blowby in the valve cover after reconnecting the blowby tube to the intake.
 

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I did the same thing on my Toyota Hilux. The issue is the system is engineered to have the intake suck the blowby out of the crankcase. Just venting into the atmosphere does not vent the pressure enough which causes stress on the piston rings and will cause additional blowby which causes a snowball effect. My Hilux only has 40,000 miles and was using oil due to the blowby. After reconnecting the vent tube to the intake it stopped using oil. The better option is to leave the crankcase blowby breather connected and delete- block the EGR. The crankcase blowby will not build up on the intake with the EGR blocked off. However with the EGR on the extreme heat cooks the crankcase blowby oil which bakes it onto the egr valve and intake. My truck was having issues not running correctly, using oil, limp mode and had heavy blowby with the crankcase venting to the atmosphere. A test, take the oil cap off the valve cover with the engine running and put your hand over it to feel the amount of blowby pressure in the valve cover. Reconnect the crankcase vent breather to the intake and then check it again. My toyota Hilux diesel has a major notable difference in less blowby in the valve cover after reconnecting the blowby tube to the intake.
Having some crank case pressure has absolutely NO effect on the rings. None.
when the diesel fuel fires there is an extream amount of pressure on the rings. Not from not having a vacuum in the crank case.
Even today’s direct injection GAS engines are building massive amounts of buildup on the intake valves because of sucking blow by out of the crank case.
Because today’s cars do not spray fuel into the intake manifold any more there is no way to wash the blow by off the valves.
You will have more blow by with a vacuum on the crank case because the vacuum sucks some of the combustion gases past the rings.
When an engine is running oil is being sprayed on the bottom of the pistons oil is running out of the every spinning part that has an oil passage.
That causes oil mist inside the engine. That mist gets sucked out of the crank case by the turbo then saturates your intercooler. Very bad ....
Then that oil mist mixes with the carbon from the exhaust in the EGR. And that makes a real mess.
The only danger from venting to atmosphere is IF the vent hose gets kinked or gets blocked off because of moisture freezing in the vent hose, it will blow the crank seals out of the motor....
So make sure the vent runs down hill so moisture will drip out.
And make sure the hose is big enough to allow the blow by to easily vent...... You don’t want pressure building up in the crank case.
 

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Turning off egr will give you higher combustion temps which should actually reduced the load on the dpf since the fuel is burned more completely. The nox production though would go through the roof though, and not just a little bit but a lot. In a write up from John Deere on developing their newer emissions compliant diesels they claim that with egr the def usage is 1-3% of fuel usage to hit emissions compliance while without egr the def usage was 6-9% of fuel consumption. So imagine a 4x increase in def usage without egr in order to hit emissions compliance. John Deere Tier 4 Final engines using EGR and SCR. . With just a 5.5gal def tank it'd only lasts you a handful of tanks before needing filled.
The EGR re burns some of the soot that would reach the DPF . By re burnin some of the soot laden exhaust you actually lower the amount of soot making it to the DPF .
Also re burning some of the exhaust lowers NOX. That means less DEF is needed to control NOX.
John Deers new Tier 4 is basically the same system we have.
GM has reduced the amount of EGR used on the new 3.0 diesel. Probably to slow down the time it takes to plug the intake.
Check out how much DEF that engine uses. It’s about 3 to 4 times more than the 2.8

If you look at the EGTs on our little diesel you will see how extremely high they are when under a load like pulling a heavy trailer. Lower combustion temps are not a bad idea.
But on the other hand dumping abrasive soot into the combustion chambers is not a good idea ether.

And what’s really bad is allowing blow by to fill your intercooler then mix with the soot and plug up the intake.
 

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Having some crank case pressure has absolutely NO effect on the rings. None.
when the diesel fuel fires there is an extream amount of pressure on the rings. Not from not having a vacuum in the crank case.
Even today’s direct injection GAS engines are building massive amounts of buildup on the intake valves because of sucking blow by out of the crank case.
Because today’s cars do not spray fuel into the intake manifold any more there is no way to wash the blow by off the valves.
You will have more blow by with a vacuum on the crank case because the vacuum sucks some of the combustion gases past the rings.
When an engine is running oil is being sprayed on the bottom of the pistons oil is running out of the every spinning part that has an oil passage.
That causes oil mist inside the engine. That mist gets sucked out of the crank case by the turbo then saturates your intercooler. Very bad ....
Then that oil mist mixes with the carbon from the exhaust in the EGR. And that makes a real mess.
The only danger from venting to atmosphere is IF the vent hose gets kinked or gets blocked off because of moisture freezing in the vent hose, it will blow the crank seals out of the motor....
So make sure the vent runs down hill so moisture will drip out.
And make sure the hose is big enough to allow the blow by to easily vent...... You don’t want pressure building up in the crank case.
Ok i will try it on my Duramax to see if it has any issues. The toyota did not work out well venting to atmosphere. I was thinking another option would be to put a bung on the exhaust after the muffler and connecting a long hose from the crankcase breather to the bung on the exhaust as a way to vent out the blowby.
 

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No, I didn't block off the CCV, I plugged up the hose to the intake that the CCV feeds. The CCV was going thru my oil separator and then venting to atmosphere. I'm certainly not at a point to try and vent the EGR to atmosphere as that would take a little engineering that I quite frankly don't have the time or drive to do. I don't know how much actual exhaust by percentage is fed from the EGR to the intake as a percentage of exhaust volume. That percentage assuming it didn't throw a code could probably be the increase in soot load and regen cycles if blocked off. Doing a block off is probably the easiest and cheapest to try and to put back if a code is set.

I'm not sure how to "reset limp mode". I've read of people resetting limp mode but I don't know how it's done. Is it as simple as clearing codes with OBD Fusion or is it a trip to the dealer?
My Hilux goes into limp mode often as I have been experimenting with blocking the egr, Venting the crankcase blowby to atmosphere etc. Just need a cheap ODB scanner. Plug into OBD port and clear codes instantly clears limp mode. Only way to really eliminate these issues a a good tuner to reflash the ecu .
 

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Discussion Starter · #19 ·
My Hilux goes into limp mode often as I have been experimenting with blocking the egr, Venting the crankcase blowby to atmosphere etc. Just need a cheap ODB scanner. Plug into OBD port and clear codes instantly clears limp mode. Only way to really eliminate these issues a a good tuner to reflash the ecu .
I have since plugged the CCV back into the intake. I have an oil separator that is catching some oil so I know it's doing it's job. My factory warranty is up in a month so I'll probably get a tune at that point. Eventually I may try blocking off the EGR to see if it sets a code. If it doesn't maybe I'll vent the EGR to atmosphere so les sooty exhaust gets to the DPF and I should use even less DEF.
 

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Ok i will try it on my Duramax to see if it has any issues. The toyota did not work out well venting to atmosphere. I was thinking another option would be to put a bung on the exhaust after the muffler and connecting a long hose from the crankcase breather to the bung on the exhaust as a way to vent out the blowby.
When you vent the crankcase to atmosphere some oil mist will come out of the hose.
That means you will lose some oil. But it’s a small price to pay to keep it out of the intercooler and EGR....
I thought of connecting the hose to the exhaust too but was afraid it would cause some back pressure in the crank case.
And there is no muffler on a 2.8 diesel.
There is so much restriction with the DOC and then the SCR and then another DOC just in front of the DPF in the same can that it’s very hard to get the exhaust out the tail pipe. The back pressure is very high.
Good luck
Be careful to make sure the the vent hose let’s the blow by freely out of the crankcase....
 
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