BlueCamaroZ28

What is the gain and is there any harm.

Red96Lt1

Very little to no gain. Free's up the engine bay.

Bastardcat

I agree. You may want to try a search for a more in-depth answer to this question.

CamaroBoy96Z28

Removing both is real easy to do. Took me a little over an hour and a half to get both the AIR pump out and block off the EGR. Red96LT1 mentioned the reason for doing it already.

19formula94

would removing either mess up emssions at all?

smokerZ28

Removing either will make you fail the sniffer and visual more than likely.

Bastardcat

Yes.

Injuneer

AIR only operates for a few minutes at startup. They generally do not include this condition in a rolling emissions test. They will probably notice it is missing if they do a "visual" inspection. Will not set a code in OBD-I, as long as there is a good fuse in the circuit. Will set a code in OBD-II unless it is programmed out.

EGR operates under moderate RPM conditions, when "lugging" the engine in too high a gear. This condition is included in some rolling emissions drive cycles, and if you are already borderline on NOx, a missing EGR system could push you over into the "fail" zone. EGR will also help prevent detonation when lugging the engine. Might notice it is missing. Will set a code in OBD-II, unless it is programmed out. May set a code in OBD-I, but it is unusual.

Niether of these systems operates at WOT, so there is nothing to be gained except maybe less 10# weight loss.

19formula94

thanks for the info guys

Josh-'04 GTO

Fred hit the nail on the head, of course! Another good point to remember is that if you have an aftermarket cam, you probably have enough overlap where the EGR is redundant anyway. The LT4 Corvette is a good example of not needing an EGR valve.

Zachz28

So deleting EGR is a for sure fail on the NOx or just a maybe?

Josh-'04 GTO

Go back and reread my last post. The '96 LT4 Grand Sport Corvette had NO EGR from the factory. GM Powertrain deemed the overlap on the LT4 cam as enough to make an EGR system unnecessary.

So there is no guarantee that no EGR will make you fail emissions, unless they catch it visually.

mike 96 ws6

what exactly makes OBD-II set a code with the EGR blocked?

meengreen 94z

Theres a vacuum line from the egr valve that measures the intake of the egr. If its sucking in clean air instead of unspent gases it will throw a code.

mike 96 ws6

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the only vaccumn line on the valve itself is the one from the EGR control solenoid that applies vacumn to the diaphram that pulls the pintle off it's seat. i don't see how the PCM knows whether or not the pintle actually moves. there's no position sensor. maybe it doesn't get the info via physical position of the valve but rather by monitoring the manifold vaccumn and looking for a change via the MAP sensor. if there's no change when the EGR solenoid commands the valve open as the PCM is expecting, it sets a code. i'm just wondering if there's a way to keep the PCM from expecting this change other than modifying the program? or connect the EGR supply tube to crankcase vent and let the EGR valve induct crankcase vapor instead of super hot exhaust gasses.