Blocking the EGR Valve

**togenshi** · 10th November 2015, 09:50 PM

Ok, so I flooded my Patrol "competition" ZD30DDti and had the car sitting for a while. Due to that my EGR unit internals rusted up. So instead of spending $700 or something stupid for another unit, I was looking to remove the entire EGR assembly completely.

The answer is "you can't". This is due to math done in the ECU whereby it compares MAP (found on the intercooler) and the MAF (air box). Unfortunately, these 2 sensors is the pulse for the engine so we cannot manipulate them without upsetting the engine. This is exasperated by the fly-by-wire throttle body whereby it would close under de-acceleration to suck in the exhaust gases (suspicion at this moment but most likely what I would do as engineer).

Luckily I managed to clean up my valve unit but I took out the the rest of it cause I aren't going back.

So what I am going to look into doing is see if the car will play ball by making a plate with a tube before the valve unit going to some clean air. Introducing a 3rd element is the only way to trick the CPU. Clean air > Exhaust gases. If clean air goes into the cylinder when its expecting dirty air... I think it should be alright.

I don't see an issue at this moment. I might have to experiment with how much pressure to apply to the intake. I do have a scan gauge 2 on hand. Just need to make plates for the exhaust manifold and EGR valve.

Also, for those that added a EGR block, leave the battery off overnight. Then in the morning start the car. DO NOT TOUCH THE THROTTLE OR MOVE THE CAR till the temperature gauge is where it should be when warmed up. This is to allow the ECU to learn about your engine. It should be fine after that.

**NissanPatrol.com.au** · 10th November 2015 09:50 PM

**Hodge** · 11th November 2015, 10:03 AM

Hey TOgenshi.
I have seen a similar concept on a YD25 C RD Navara. What the guy basically done is, put some sort of a Y pipe on the clean air intake. One goes to the normal intake as per usual, and the other one was piped into the EGR system. This kept the original flow of things but instead of the dirty gases, clean air was flowing through the EGR pipes, keeping the system happy, while keeping the engine cleaner.

**mudski** · 11th November 2015, 11:19 AM

Originally Posted by Hodge

Hey TOgenshi.
I have seen a similar concept on a YD25 C RD Navara. What the guy basically done is, put some sort of a Y pipe on the clean air intake. One goes to the normal intake as per usual, and the other one was piped into the EGR system. This kept the original flow of things but instead of the dirty gases, clean air was flowing through the EGR pipes, keeping the system happy, while keeping the engine cleaner.

After all that a 10buck egr plate would do a better job and is much quicker to fit... Lol.

**togenshi** · 11th November 2015, 12:06 PM

I already took the entire EGR assembly out. You should see how much more room I have to access everything. It aren't going back. I can replace the fuel filter without killing my fingers. Also I get access to most of the hoses which is a plus for when doing bush mechanics.

I got the exhaust side EGR blocked. Getting a few components for the water cooling today. A T-junction, joiner and/or spare hose is required to complete the water cooling circuit. Also will be making the EGR plate with the hole in it. I'll use some hoses to a small breather filter initially.

**threedogs** · 11th November 2015, 01:23 PM

Instead of using TEE's have you looked at using "Y's"
far less cavitation IMO

**togenshi** · 11th November 2015, 05:53 PM

Its for one of the smaller water hoses that goes into the throttle body I think?

**togenshi** · 19th November 2015, 05:49 PM

Step one. Got water hose bypass installed. Used a Ford Falcon heater hose and a T-junction to complete the cycle. EGR value is not getting water cooled any more. No need to.

Reinstalled my EGR valve and without a cover, switched on my car. Got P0400 error. Had to leave my battery off over night. Started the car and waiting till it heated up. No P0400/P0401 error so far. Will be making plate for it and a hose to after the air filter this weekend.

**foggs** · 19th November 2015, 07:48 PM

Originally Posted by togenshi

.....Also, for those that added a EGR block, leave the battery off overnight. Then in the morning start the car. DO NOT TOUCH THE THROTTLE OR MOVE THE CAR till the temperature gauge is where it should be when warmed up. This is to allow the ECU to learn about your engine. It should be fine after that.

I wasn't aware of this piece of info, I've had it blocked now for over a month.. is it still worth doing this?

**togenshi** · 23rd November 2015, 02:53 PM

If it works, don't touch it I guess.

As for me, got plate installed with air hose attachment fitted in however decided to do belt tensioner while I am at it and while getting the shroud off, I damaged my radiator...

*sigh*

edit: any changes to the whole combustion process, I would recommend having the CPU relearn so it can work with updated variables. Such as an increase in air flow or another intercooler.

**Rossko07** · 24th November 2015, 08:44 AM

Originally Posted by togenshi

Also, for those that added a EGR block, leave the battery off overnight. Then in the morning start the car. DO NOT TOUCH THE THROTTLE OR MOVE THE CAR till the temperature gauge is where it should be when warmed up. This is to allow the ECU to learn about your engine. It should be fine after that.

What exactly will the ecu relearn?

Will this method prevent the car throwing EGR flow codes?

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