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huge wall of text
You're right, EGR on modern diesel engines is far more complex that most people (including myself) think.

I do agree with you that a delete tune will get rid of EGR and also block that throttle plate wide open. Depending on where it is in the engine intake, I wonder how difficult it would be to remove the throttle plate?
The throttle body is right up top easy to access. I don't remember off top of my head if the throttle blade is pinned in place or screwed, so not sure how easy it would be to remove the blade.
 

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The throttle body is right up top easy to access. I don't remember off top of my head if the throttle blade is pinned in place or screwed, so not sure how easy it would be to remove the blade.
I need to investigate. If it's something like popping a couple screws off to remove the butterfly valve, I'm curious if it would throw a CEL if it were removed. If the valve actuation is measured only by whatever electronic or vacuum actuator exists to turn the valve, it's possible the ECU could get "correct" throttle plate position readings even if the throttle plate itself were removed.
 

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Is there anyway to make sure the throttle plate is wide open all the time?
You'd probably have to do one of three things:
1. Disable (disconnect) any electronic throttle adjustment if the plate is held wide-open by a spring. This would likely give you a CEL on the instrument panel.
2. Remove the throttle plate if it's attached to an actuator with screws or some other fastener. This *MIGHT* give you a CEL if there is some other engine sensors that detect things are going wrong. If the only input to the ECU is a throttle position sensor, it might not trigger a CEL.
3. Aftermarket tuning for the engine.

If this engine is like other diesel engines, the throttle plate is also there for shutdown of the engine. To prevent something that a more than typical shuddering of the engine when it shuts down, some diesel engines snap the throttle plate closed so the pistons are fighting against vacuum to quickly stop the engine.
 

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I don't know definitively what's going on under the hood, but I can tell you there's almost zero engine braking.
that sux

gen1 td uses the variable vanes of the turbo for engine braking....i go down a 6 mile 10% hill near my house in 3rd...holds steady 65mph
 

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If the EGR valve were unplugged, what is the worst outcome? If it's just a CEL on the instrument cluster and basically nothing else, I don't have a problem with that.

I'm obviously not an engine designer, but why haven't modern diesel engines been changed to take exhaust gases from after the DPF? It seems like it would be better/easier to take clean, soot-free exhaust gases from after the DPF and put them into the intake right before the turbocharger.
 

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The throttle body is right up top easy to access. I don't remember off top of my head if the throttle blade is pinned in place or screwed, so not sure how easy it would be to remove the blade.
What is your knowledge of what happens if you unplug the EGR valve? Does it stay closed and just display a CEL on the dashboard with no other detrimental effects?
 

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The throttle body is right up top easy to access. I don't remember off top of my head if the throttle blade is pinned in place or screwed, so not sure how easy it would be to remove the blade.
What is your knowledge of what happens if you unplug the EGR valve? Does it stay closed and just display a CEL on the dashboard with no other detrimental effects?
An unplugged EGR valve will set NUMEROUS codes, some type A, some type B. You're likely to get a "Service Emission System" message, and may even go into tamper reduced power
 

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An unplugged EGR valve will set NUMEROUS codes, some type A, some type B. You're likely to get a "Service Emission System" message, and may even go into tamper reduced power
How often does the ECU check for EGR valve function?

I ask because a friend of mine has a Jeep Liberty with the CRD engine. That is over a decade ago, so different emissions system and no DPF. Still, the fix for those engines is to wire the EGR valve with a switch in the cab. When you start the vehicle you leave EGR on for 30-45 seconds and that is apparently the length of time the ECU checks for EGR function. After that you can flip the switch to turn off EGR and nothing happens (no CEL). You save all the soot from going into your intake and your fuel economy jumps by 10-15%.
 

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Has anyone unplugged the EGR in 1.6l diesel?
I did, as an experiment.

I have friends with some Cummins pickups in the 2007-2012 range. Their choices of emissions tinkering include some unplugging EGR and just living with a constant CEL that is a "soft" malfunction, I.E., it doesn't affect functioning of the vehicle.

My unplugging of the EGR resulted in an immediate CEL when I started the car and a warning message that I was 75 miles away from reduced function of the engine (limited to 65 mph top speed). I assume that if I go past that it will drop to 55 mph, and then down to the 4 mph speed limit that results when you run out of DEF. It's a "hard" malfunction in that it impedes functioning of the vehicle.
 

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I did, as an experiment.

I have friends with some Cummins pickups in the 2007-2012 range. Their choices of emissions tinkering include some unplugging EGR and just living with a constant CEL that is a "soft" malfunction, I.E., it doesn't affect functioning of the vehicle.

My unplugging of the EGR resulted in an immediate CEL when I started the car and a warning message that I was 75 miles away from reduced function of the engine (limited to 65 mph top speed). I assume that if I go past that it will drop to 55 mph, and then down to the 4 mph speed limit that results when you run out of DEF. It's a "hard" malfunction in that it impedes functioning of the vehicle.

That's what will happen with any newer diesel. It's mandated by the feds that the engine will derate with most emissions malfunctions.

100% because of the federal emissions laws. 0% because it'll hurt the engine.
 

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I emailed and received response that Oz Tuner has done the necessary deletes but are working on a security method...So basically they would rather develop something and keep it from the market than release it and have people copy there work.
 

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At least you got a response, my inquiry about a month ago was never addressed... Glad to hear there is something in the works though, being that the production of our cars was halted. I'm coming up on the end of my power-train, eager to modify once I get there!
 

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View attachment 271525 For my education, what is the issue (system function, failures, resulting impact) with the EGR circuit in the GEN2 Diesel.
The issue? Regarding my recommendation to not install a catch can on it?
The issue is that it's exhaust gas....It's fairly hot. Besides any temp related concerns it's also a fairly complex arrangement and not conducive to installing one, additionally a catch can isn't going to trap exhaust particulate matter, so I don't see the point.
 

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I apologize about not being verbose enough - my rephrased question is - What is it about the Chevrolet GEN2 Diesel's EGR system that causes it to fail or cause other issues? Could an improvement (perhaps from another Diesel system made by another manufacturer) improve upon Chevrolet's design to prevent or prolong the EGR issue?
 
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