Last Updated: 01/29/2022 @ 04:19 pm
Member Credit: Fuzzyknub / EddyMaxx
If you eliminate your EGR valve, you’ll likely get a P0400 Exhaust Gas Recirculation Flow Malfunction trouble code. But no worries, here’s what you need to do to get rid of the code.
EGR stands for Exhaust Gas Re-circulation. It takes the exhaust and recirculates it back into the engine so it will burn any unburnt fuel left to create a better emission. It only does a small portion, not all of it the cats take care of most of it. The EGR is a federally mandated system designed to control tailpipe exhaust emissions.
The EGR system reduces emissions by returning small amounts of metered exhaust gases back to the engine intake. The theory is that by using exhaust gas as part of the intake air/fuel mixture, there is less oxygen to burn, which lowers the temperature of combustion. Cooler cylinder head temps lead to less formation of pollutants, specifically nitrogen oxide (NOx) compounds.
The reason most people delete the system is it really doesn’t work after 20+ years of built up gunk and crap in the system. If you take yours off, I will bet you have carbon build up in the tubes and nothing i getting through that. All its doing now is directing all of it into the exhaust system. Another reason is it ends up being a major source to a vacuum leak. All the EGR valve is, is a rubber diaphragm. They usually fail after 10-15 yrs or after 100k miles. They don’t make parts for it anymore or if they do it is insanely expensive.
What are the benefits and why do this?
- The majority of Nissan owners do this modification when they install headers and eliminate the EGR valve. When eliminating the EGR, it throws a code. This mod makes it easy to keep the headers and avoid CEL codes.
- It’s a very simple mod to do and won’t effect your engine performance.
- There have been no major known issues when doing this modification. The EGR is designed to be mainly operational when the engine is cruising and already warmed up. Removing the EGR should not put the engine under increased risk. The EGR is only working when the engine is under minimal stress.
EGR (What you will be eliminating/deleting)
1. EGR Block-off Plate
Buy the EGR blockoff plate from NWP (you can also make your own). This will go on the intake manifold when you disconnect the piping from the EGR system. If you are doing an HR swap or have a 07-08 Maxima, then you don’t need to do this. They cost $35 bucks from NWP.
2. EGR Exhaust Plug
For the exhaust side plumbing you’ll either need a plug for the exhaust bung or have headers that don’t have an EGR bung. The EGR exhaust bung plug is a M24 plug. You can actually buy it directly from Nissan using this: Plug Taper – Nissan (14052-21R00)
3. EGR Temp Sensor
This is the smallest of the 2 sensors on the EGR piping under the hood. You can either leave it in the engine bay reading ambient air temp or you can trick the ECM by sticking a 10k ohm resistor in the female connector (as my picture illustrates above). I don’t believe you will go into limp mode if you totally remove this sensor and don’t do the resistor trick but you will throw a P0406 (EGR flow sensor A circuit high input) code.
RadioShack Part #: 2711335 10K-Ohm 1/4-Watt Carbon Film Resistor (5-Pack)
Important Note: Make sure resistor is 10K-Ohm not 10-Ohm.
4. EGR Valve Sensor
I removed this sensor (4 screws secure it to the piping) from the piping, left it plugged in to the factory harness and zip tied it to some other wiring under the hood. This one is a big deal as you WILL go into limp mode and can’t rev over approx 3k rpms if you take this sensor out from under the hood! Ask me how I know
5. Coolant Lines
If I remember correctly my coolant lines went to the EGR valve, out to the throttle body and back out to the return plumbing. I basically just took the EGR out of the lineup. So the coolant line runs straight to the Throttle body and back out to the return plumbing. I’ll delete the coolant lines to the throttle body at a later date and time as I was doing a LOT of mods at once and didn’t feel like fooling with it at that time & point.
That should do it!
Update from EddyMaxx (June 24th, 2018)
I performed this on my 2004 Nissan Maxima and drove 3K+ miles. No issues or CEL from the EGR delete. The emissions readiness monitors also pick up EGR as PASS!
Photo of my car (Taken Sept 2nd, 2018):