EGR Delete

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tin

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Post Date: Mon, 09/12/2013 - 5:22pm

Hello!

Has anyone on the forum had any experience with deleting their EGR system? What effects does this have? Check engine lights? Idle problems? Etc...

Doing a basic search on EGR function has revealed that the recirculated gasses are an essential element in the combustion mixture and that deleting/blocking the EGR system will effect engine speed at low RPM. On the other hand there are plenty of Mitsubishi forums where people are blocking and deleting their EGRs without any adverse effect. The Mistubishi engine manual states that the EGR valve is closed during wide open throttle, idle and warmup. So it is functioning only during normal driving conditions. Apparently there are also simple electronic circuits designed to trick the computer into thinking that the EGR is functioning when it's not even there. Ghost EGR:)

My reason for exploring this option is to minimise carbon buildup in a direct injection intake system of 4G93 GDI engine. This is a big problem for me!

ThreeSummers

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Post Number: #1
Post Date: Wed, 11/12/2013 - 11:48pm

I'd also like to see an

I'd also like to see an answer to this as my 2.0 4G94 seems to be suffering too.

tin

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Post Number: #2
Post Date: Thu, 12/12/2013 - 5:21am

Blocked

As it stands my EGR is blocked up with soot at the place where it enters the intake plenum. It's absoletely clogged so there is no exhaust gas flow at any time. The engine has a low idle problem and I haven't been able to figure out whether the disfunctional EGR is causing this or not. It's definately a possible cause but when looking up the problem on various forums the solutions vary so much, anything from ignition components to vacuum leaks to maladjusted throttle position sensor or MAF or even dirty injectors.

I would like to remove the EGR system entirely as I have the head off right now, but I would like to be certain that the EGR is not responsible for my low idle.

fordem

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Post Number: #3
Post Date: Thu, 12/12/2013 - 6:28am

A blocked EGR system is unlikely to cause low idle speed.

Under normal circumstances EGR is disabled at idle - a sticking EGR valve that allows EGR flow at idle will result in low, uneven idle & stalling, especially as the vehicle is coming to a stop

bob_oz

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Post Number: #4
Post Date: Thu, 12/12/2013 - 8:48am

fuel grade

The GDI motors need a high grade of low-sulphur fuel. if they are run on lower fuel they soot up.

try changing your fuel grade to the highest you can - I would err against blocking your EGR

fordem

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Post Number: #5
Post Date: Thu, 12/12/2013 - 1:30pm

The GDI motors will soot up regardless of fuel grade ...

The EGR is actually one of, if not the primary cause, of soot in the GDI intake, and according to what I've read, Mitsubishi in Europe have been blocking it, and reprogramming the ECU to compensate.

Think about it - how can soot, which is partially burned hydrocarbons, get into the intake system of an internal combustion engine?

On a carburetted or "normal EFI" (ie non direct injection) engine, if fitted with EGR (not all of them are so equipped), soot from the exhaust gets "re-routed" to the intake via the EGR, but rather than building up in the intake, it is "washed away" by the gasolene in the incoming fuel-air mixture - this does not happen with the GDI engines because the fuel is injected directly into the combustion chamber.

The 4G93 & 4G94 GDI engines represent the "first generation" of mass produced gasolene direct injection engines and suffer badly from soot in the intakes, the problem has pretty much plagued all manufacturers using direct injection and many are still developing ways to deal with the problem - one of which is to use a combination of direct injection and port injection to wash the soot out of the intake into the chambers where it can be burned.

Two of the three vehicles I own were not equipped with EGR from the factory, I don't think a blocked EGR on the GDI iO triggers an ECU fault code and the only reason I would hesitate to block the EGRis if the vehicle has to pass some sort of air care or smog testing.