EGR Delete Option?

TestDriver · **Posted:** Thu May 18, 2017 10:51 am

I'm in the middle of a head stud install and considering gutting the EGR system. But, before removing it, I have a possible option in mind. Has anyone tried routing fresh air off the turbo outlet side to the EGR inlet instead? Conceptually, this air would be under marginally higher pressure than the post intercooler air so it would flow into the intake tract. Plus, the FCV closing promotes flow there as well. If the EGR has temperature sensing capability, this air would also be quite a bit hotter than post IC air.

Any thoughts?

flash7210 · **Posted:** Thu May 18, 2017 1:51 pm

Dont do it.

The EGR valve is just a solenoid, it senses nothing.
The method you describe would cause a low power underboost condition.

GordnadoCRD · **Posted:** Thu May 18, 2017 2:07 pm

Bypassing the intercooler will cause much hotter and much less dense air to be delivered to the intake manifold. You will lose a substantial amount of power. Much more than your marginally higher (theoretical) pressure. You would need a new tune with much less fuel to correct the black smoke situation caused by that modification also.

Flash X2
Don't do it.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

X3; nothing else to add from me.

WWDiesel · **Posted:** Thu May 18, 2017 3:02 pm

X4, Bad idea!!! :banghead:

Just block it off or totally remove all the junk with a Weeks Kit from Sasquatch Parts! :wink:

TestDriver · **Posted:** Thu May 18, 2017 3:24 pm

Perhaps I'm confusing some. The setup I'm thinking about would bleed off a very small amount of compressed air. Only enough to "fool" the control module into not setting off a code. What normally happens if the EGR is blocked off but the wiring is left in place?

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

TestDriver wrote:

Perhaps I'm confusing some. The setup I'm thinking about would bleed off a very small amount of compressed air. Only enough to "fool" the control module into not setting off a code. What normally happens if the EGR is blocked off but the wiring is left in place?

Why re-invent the wheel? Fixes for this problem are already in place, and the risks in all of these alternative fixes are mitigated, if not outright eliminated. You do not know what may happen if you start fooling around with diverting turbo pressure. The reasons to NOT do this as described above are all well reasoned likely outcomes if you do this. At the VERY least you will lose power; NEVER a good thing.

I believe you will get a check engine light and a code thrown if you simply block off the EGR. Do yourself a favour; get a Green Diesel Engineering set of tunes while you still can; one for the engine, and another matching tune for the transmission. Problem solved.

WWDiesel · **Posted:** Thu May 18, 2017 4:07 pm

TURBO-DIESEL-FREAK wrote:

TestDriver wrote:

Perhaps I'm confusing some. The setup I'm thinking about would bleed off a very small amount of compressed air. Only enough to "fool" the control module into not setting off a code. What normally happens if the EGR is blocked off but the wiring is left in place?

Why re-invent the wheel? Fixes for this problem are already in place, and the risks in all of these alternative fixes are mitigated, if not outright eliminated. You do not know what may happen if you start fooling around with diverting turbo pressure. The reasons to NOT do this as described above are all well reasoned likely outcomes if you do this. At the VERY least you will lose power; NEVER a good thing.
I believe you will get a check engine light and a code thrown if you simply block off the EGR. Do yourself a favour; get a Green Diesel Engineering set of tunes while you still can; one for the engine, and another matching tune for the transmission. Problem solved.

If you install a block off plate, you may or may not get an occasional DTC; I ran for well over a year with just a block off plate and I think I only got 2-3 DTC pertaining to P0101 before I installed the Weeks Elbow Kit and a DIY tune!
Simply block it off with a block off plate and install a Do-It-Yourself Tune available on this forum if you are just wanting to leave all the parts in place for visual reasons.
There is absolutely nothing to gain from trying to pipe turbo air through the system but certainly issues that could be created by doing this!!!! :roll:

Block off Plate Dimensions and install instructions:> viewtopic.php?f=5&t=76576

DIY Tunes and instructions:> viewtopic.php?f=98&t=78418

TestDriver · **Posted:** Thu May 18, 2017 4:40 pm

Simply put, I want to forgo the cost. GDE is actually minutes from my house. I've bought stuff from Keith before but I don't want to spend the ''tunes'' money. Likewise, I'm not going to toss nearly $300 to someone for a hose and some clamps. Admitedly, that's a simplification but, c'mon! If I went that way, I'd make the hardware myself.

I just read on the manual that the control module monitors the flow through the EGR valve. It has to. Otherwise, it would be unable to set off codes. This monitoring is why we can't simply block off the exgaust gasses and what I'm looking to recreate but with clean air and no trouble codes. I think what I'll do is, I'll make it reversible so I can just go back to stock.

TURBO-DIESEL-FREAK · **Joined:** Sat Apr 17, 2010 3:29 pm **Posts:** 1167

TestDriver wrote:

Simply put, I want to forgo the cost. GDE is actually minutes from my house. I've bought stuff from Keith before but I don't want to spend the ''tunes'' money. Likewise, I'm not going to toss nearly $300 to someone for a hose and some clamps. Admitedly, that's a simplification but, c'mon! If I went that way, I'd make the hardware myself.

I just read on the manual that the control module monitors the flow through the EGR valve. It has to. Otherwise, it would be unable to set off codes. This monitoring is why we can't simply block off the exgaust gasses and what I'm looking to recreate but with clean air and no trouble codes. I think what I'll do is, I'll make it reversible so I can just go back to stock.

O.K., then... If you have the means to do so; make your own intake elbow, and do the DIY tune. Absolute minimal cost there. Do not try to out-think what the engineers have designed for this engine... you could be risking serious consequences by experimenting. Unless you are a automotive engineer, then what you are attempting is like playing with fire.

This is not a small block Chevy engine... it is not like you can get a quick repair or parts if something goes wrong with a CRD engine, and parts are EXPENSIVE! Do the upgrades that have been established to work reliably with this engine.

GordnadoCRD · **Posted:** Thu May 18, 2017 5:13 pm

TestDriver wrote:

Simply put, I want to forgo the cost. GDE is actually minutes from my house. I've bought stuff from Keith before but I don't want to spend the ''tunes'' money. Likewise, I'm not going to toss nearly $300 to someone for a hose and some clamps. Admitedly, that's a simplification but, c'mon! If I went that way, I'd make the hardware myself.

Viewpoint understood

I just read on the manual that the control module monitors the flow through the EGR valve. It has to. Otherwise, it would be unable to set off codes.

This is not technically correct.
There is no exhaust flow monitoring involved.
Also, it is not a simple open-close operation.
What it does is look at many things, such as current boost, current load% current throttle input, ETC, and it makes judgements based on all parameters against it's programming, and determines what % to tell the EGR solenoid to open the valve.
It uses the same square wave signal that it sends to every solenoid it commands, from Glow Plugs, to Fuel Pressure solenoids.
This signal is what it "monitors". Not from a sensor or observation point of view, but as the one sending the actual command.
Actual exhaust gas flow means nothing to it.

This monitoring is why we can't simply block off the exhaust gasses and what I'm looking to recreate but with clean air and no trouble codes. I think what I'll do is, I'll make it reversible so I can just go back to stock.

Well you are obviously free to do as you like, but I can tell you with 100% certainty that you are starting on a project with a complete misunderstanding of how the system works.

You can accomplish what you are trying to do by simply installing a blockoff plate, and removing the FCV "butterfly" valve, and leave the FCV and EGR valve electrical connectors in place. Heavier, and not as good as the Weeks kit, and you still have all the water hoses in place with their potential (fairly common) leaks, but it will do what you are trying to accomplish. What you are proposing to do, will not.

joe_ · **Posted:** Thu May 18, 2017 5:15 pm

TestDriver wrote:

I just read on the manual that the control module monitors the flow through the EGR valve. It has to. Otherwise, it would be unable to set off codes. This monitoring is why we can't simply block off the exgaust gasses and what I'm looking to recreate but with clean air and no trouble codes. I think what I'll do is, I'll make it reversible so I can just go back to stock.

It doesn't monitor the flow through the EGR valve per se, it looks for a drop in air flow at the mass airflow sensor (right by the air filter box) when the EGR valve is open, and assumes that loss in flow is due to exhaust gas being rerouted back into the intake manifold. If you pipe compressed air from the turbo outlet to the exhaust side of the EGR valve, that air has already passed through the MAF sensor and won't be causing the reduction in flow at the MAF sensor during EGR valve operation that the PCM is expecting. Long story short, this won't prevent an insufficient EGR flow any more than just blocking off the EGR valve, since either situation results in the same amount of airflow at the MAF sensor.

CHessMaster · **Posted:** Thu May 18, 2017 8:57 pm

[/quote] It doesn't monitor the flow through the EGR valve per se, it looks for a drop in air flow at the mass airflow sensor (right by the air filter box) when the EGR valve is open, and assumes that loss in flow is due to exhaust gas being rerouted back into the intake manifold. If you pipe compressed air from the turbo outlet to the exhaust side of the EGR valve, that air has already passed through the MAF sensor and won't be causing the reduction in flow at the MAF sensor during EGR valve operation that the PCM is expecting. Long story short, this won't prevent an insufficient EGR flow any more than just blocking off the EGR valve, since either situation results in the same amount of airflow at the MAF sensor.[/quote]

This is correct.
Put another way:
When the PCM commands the EGR to open via PWM (Pulse Width Modulation) it knows that (for example) 50% of EGR open time equals "X" amount of air flow displaced from the fresh air intake system (since it comes from the exhaust system instead of through the air filter). The PCM must see this corresponding drop in fresh air via monitoring the MAF sensor output. If the 2 are equal (within a set parameter), the PCM assumes that the EGR system is working.

So; to do a EGR "bypass", you would need to plumb the EGR system so that when the EGR valve opened, instead of getting exhaust gasses, you let fresh filtered air through the EGR valve (from anywhere except AFTER the MAF sensor). This would satisfy the above conditions for the PCM and would not turn on any EGR related code(s).

WWDiesel · **Posted:** Thu May 18, 2017 9:04 pm

I suspect you will find huge differences between turbo boost pressure entering the EGR valve verses exhaust manifold pre turbo pressures from where the EGR normally gets it's supply!
I still fail to understand the logic in all of this when a simple EGR block-off plate along with a FREE DIY tune will solve all these problems and issues. Cost is basically $0!
Seems like a big waste of time and energy to me, but it is your vehicle so do as you please! Several of us on here have tried to steer you in a better direction but it looks like it is to no avail.... :shock:

GordnadoCRD · **Posted:** Fri May 19, 2017 1:49 am

I sort of suspect CHessMaster knows that P0234 is not an EGR-related code, and that it Will result in a limp home situation.
Oh Well. Sometimes I have to learn the hard way too.
WWDiesel x 2

TestDriver · **Posted:** Fri May 19, 2017 9:02 am

CHessMaster wrote:

It doesn't monitor the flow through the EGR valve per se, it looks for a drop in air flow at the mass airflow sensor (right by the air filter box) when the EGR valve is open, and assumes that loss in flow is due to exhaust gas being rerouted back into the intake manifold. If you pipe compressed air from the turbo outlet to the exhaust side of the EGR valve, that air has already passed through the MAF sensor and won't be causing the reduction in flow at the MAF sensor during EGR valve operation that the PCM is expecting. Long story short, this won't prevent an insufficient EGR flow any more than just blocking off the EGR valve, since either situation results in the same amount of airflow at the MAF sensor.[/quote]

This is correct.
Put another way:
When the PCM commands the EGR to open via PWM (Pulse Width Modulation) it knows that (for example) 50% of EGR open time equals "X" amount of air flow displaced from the fresh air intake system (since it comes from the exhaust system instead of through the air filter). The PCM must see this corresponding drop in fresh air via monitoring the MAF sensor output. If the 2 are equal (within a set parameter), the PCM assumes that the EGR system is working.

So; to do a EGR "bypass", you would need to plumb the EGR system so that when the EGR valve opened, instead of getting exhaust gasses, you let fresh filtered air through the EGR valve (from anywhere except AFTER the MAF sensor). This would satisfy the above conditions for the PCM and would not turn on any EGR related code(s).[/quote]

Ah! This is the kind of information I was looking for. So no, my original concept won't work. It would take airflow not accounted for by the MAF.

By the way, I am an automotive engineer. But, I'm not in powertrain or emmisions. I'm in dynamics and kind of subscribe to Carrol Smith's views on engines. That is, untill I have to put money into them. I'll delve into the DIY tunes now.

Thanks to everyone for the input!

jws84_02 · **Posted:** Fri May 19, 2017 4:12 pm

Why not just cut the stock pipes, fold them over, then weld them shut, then reinstall them. Then install a diy tune. That's what I do on all my deletes

TestDriver · **Posted:** Fri May 19, 2017 7:14 pm

jws84_02 wrote:

Why not just cut the stock pipes, fold them over, then weld them shut, then reinstall them. Then install a diy tune. That's what I do on all my deletes

Precisely my plan.

No $300 hose and clamp kit!

WWDiesel · **Posted:** Fri May 19, 2017 8:32 pm

TestDriver wrote:

jws84_02 wrote:

Why not just cut the stock pipes, fold them over, then weld them shut, then reinstall them. Then install a diy tune. That's what I do on all my deletes

Precisely my plan.
No $300 hose and clamp kit!

Even simpler than that; make a block off plate out of soup can lid or some other similar thin metal, slide it in between the feed tube and the EGR valve and you are done!
Cost is $0, and can be done in a few minutes with no welding involved or R&R of the EGR feed tube required.... :idea:

Block-off plate dimensions posted earlier in this thread! :wink:

EGR Delete Option?

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