jtcz28

I was looking into getting Jet hot LT's but was looking into what all I need to do if I got them without emisions. What all do I need to do to delete the Air and EGR and the pros/cons of doing this. Thanks!

-Justin

Injuneer

The issue is the SES light and codes you will get for the missing AIR and EGR in OBD-II. It is possible to have both the AIR and EGR diagnostics turned off in the PCM, but that will result in two "system not ready" errors when they hook the emissions computer to your PCM. Some states allow 2 "not readies".

If you delete the after-cat O2 sensors, and have them "programmed out", now you have three "not readies". The alternative here is O2 "sims" to eliminate the code without reprogramming.

There is an alternative on the EGR as well. There a spoof cricuit floating around that inserts a resistor in the MAP sensor circuit when the EGR solenoid is supposed to activate, tricking the PCM by showing the required change in MAP sensor reading when the EGR system is cycled by the PCM. You'd have to do a search for someone that has the circuit.

There are no performance advantages from deleting AIR or EGR, other than some minor weight reduction. Neither system operates at WOT. It would eliminate the possibility of a leaking EGR valve, which would hurt performance. And if you don't have cats, there's no need for the AIR.

You also need to consider whether you need to pass a "visual" emissions inspection. They might notice the AIR and EGR are not connected.

jtcz28

So were would I find a EGR and AIR delete package? or write up?

-Justin

2cub49

The spoof circiut uses a car alarm relay or such. Two wires are run from the wires going to the EGR valve. It doesn't matter which wire you put to which +or - side of relay as either way will work. Just make sure the relay closes when you apply power to it and the ciciut goes on. Some relays have 5 posts with one for having it on and one for having it off when it closes. You'll have to pick the right one.
The other 2 wires go to the center and rear wires at the MAP sensor with a 75 ohm or 2 150 ohm resistors in parallel spliced into 1 of the wires.
So when the pcm commands the egr to open it actually engages the relay which puts a 75 ohm resistance over the rear 2 wires on the MAP sensor which fools the pcm into thinking the correct amount of exhaust gas has entered the manifold and therefore no PO400 code.
I think you don't even need an EGR valve in place for this to work.
However 5 months after putting this in, my car would just cut out after a block or 2 and it turned out my MAP went bad which almost never happens.
I unhooked the relay and within a day the car threw the PO400 code.I have Proscan and 0BD2SPY which both showed me that the EGR monitor read ready even though the SES light was on.
I have LT-1 Edit and there's a way to program the EGR to impossible values that guarantees the pcm will not command the EGR valve to open and the monitor will read ready after some miles of driving.
However after 300 miles the monitor was still not reading ready, so I reset the EGR to the stock values and set the SES light off for PO400.
After reflashing the pcm the EGR monitor read ready after 25 miles and the light stayed off so I think that's the best way to deal with the EGR if you have OBDII tuning software.
02 simms will give you those 2 02 monitors so you'll have the 3 out of 5 that you need if both reset after a reflash of the pcm.
Twice I've had both 02s read ready and twice only the 02 heater read ready at the 2 tanks of gas mark.
I kept my AIR and that montor reads ready but it takes about 2 tanks of gas to reset.
I passed my last inspection with the spoof relay for the EGR, 02 simms for the rear 02s with only the 02 heater reading ready and the AIR ready.