EGR theory

Jackie chan

Member
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Pro5
I have an idea that i need to run by you guys regarding the deletion of the egr. This is most commonly done by cutting the pipe, capping the header, and throwing a breather filter on the pipe. This lets unmetered air into the intake manifold which could cause a lean condition. Many have had no ill effects from doing this, but it seems as though the results vary from car to car. Some get a cel, some dont. If you block off the valve completely, you will definitely get a code. My idea is if you cut the pipe, capped off the header, and then ran a hose from the pipe to a T off one of the other vacuum lines. This would cause the egr to suck air that has already been accounted for by the MAF. I havent heard anyone with this idea yet and I just want some input. Thanks
 
Hhmmmh.


My thoughts:
EGR cools the cylinder temps. You may induce a knock by doing this...

The car already runs pig-rich at WOT now... Would this make it worse?

Why would just isolating the EGR flow cause a CEL? As long as the solenoid still opens/closes the valve - it should not generate a code. The EGR doesn't measure flow...

meh.
 
There is an EGR "boost" sensor that looks for a change in pressure when the valvle is opened/closed. If this change is not detected the CEL is triggered. Since the sensor is hooked up the vacuum system I'd think your proposal would not cause a change in pressure sufficient enough to avoid the CEL.

I guess the bigger question is why do you need/want to remove the EGR? The ECU is tuned to compensate for it operating so unless you have a mechanical need to remove it (e.g. exhaust manifold doesn't have the EGR port) there's no benefit.
 
There is an EGR "boost" sensor that looks for a change in pressure when the valvle is opened/closed. If this change is not detected the CEL is triggered. Since the sensor is hooked up the vacuum system I'd think your proposal would not cause a change in pressure sufficient enough to avoid the CEL.

I guess the bigger question is why do you need/want to remove the EGR? The ECU is tuned to compensate for it operating so unless you have a mechanical need to remove it (e.g. exhaust manifold doesn't have the EGR port) there's no benefit.

also, EGR only operates during cruise. if its working, keep it. if its not working, replace the valve.
 
I have an idea that i need to run by you guys regarding the deletion of the egr. This is most commonly done by cutting the pipe, capping the header, and throwing a breather filter on the pipe. This lets unmetered air into the intake manifold which could cause a lean condition. Many have had no ill effects from doing this, but it seems as though the results vary from car to car. Some get a cel, some dont. If you block off the valve completely, you will definitely get a code. My idea is if you cut the pipe, capped off the header, and then ran a hose from the pipe to a T off one of the other vacuum lines. This would cause the egr to suck air that has already been accounted for by the MAF. I havent heard anyone with this idea yet and I just want some input. Thanks

Odd you should say that. I did some work on my MPV last weekend. The EGR valve has one extra connection the Protege5 doesn't have. It has one point where exhaust gas comes from the exhaust manifold. There's another point where air goes into the intake manifold. Then, there's this rubber hose that goes from the EGR valve to the air box on the filtered air side of the airbox. I don't think it's to feed exhaust gases into the intake air because that would dirty the MAF sensor. I think it's feeding fresh air into the intake manifold. It's a V6 so getting to the rear bank of cylinder head that required the removal of the intake manifold which required detachment of the EGR valve.
 
Odd you should say that. I did some work on my MPV last weekend. The EGR valve has one extra connection the Protege5 doesn't have. It has one point where exhaust gas comes from the exhaust manifold. There's another point where air goes into the intake manifold. Then, there's this rubber hose that goes from the EGR valve to the air box on the filtered air side of the airbox. I don't think it's to feed exhaust gases into the intake air because that would dirty the MAF sensor. I think it's feeding fresh air into the intake manifold. It's a V6 so getting to the rear bank of cylinder head that required the removal of the intake manifold which required detachment of the EGR valve.

that rubber hose is just a breather vent to help evacuate any water vapor that might collect and cause the valve to rust and not work properly. the rubber tube has no no additional input to the function of the valve.
 
ah! okay.

There is an EGR "boost" sensor that looks for a change in pressure when the valvle is opened/closed. If this change is not detected the CEL is triggered. Since the sensor is hooked up the vacuum system I'd think your proposal would not cause a change in pressure sufficient enough to avoid the CEL.

I guess the bigger question is why do you need/want to remove the EGR? The ECU is tuned to compensate for it operating so unless you have a mechanical need to remove it (e.g. exhaust manifold doesn't have the EGR port) there's no benefit.
 
that rubber hose is just a breather vent to help evacuate any water vapor that might collect and cause the valve to rust and not work properly. the rubber tube has no no additional input to the function of the valve.

Evaucate? So you're saying it allows air within the valve body to vent out this tube and into the air intake? I'm guessing it's when the EGR valve is closed so exhaust gas is not recirculating into the air box.
If it's just to vent out air, why would they connect it to the air box rather than keep the other end of the tube to remain unconnected to anything and vent out air into the atmosphere?
Just curious.
 
The "Canadian" version of the EGR has coolant line attachments as well as that vent tube,... however it isn't normally connected to the intake and just stuck in the frame somewhere. Everyone who installed one of these has never had a problem with their EGR since.

For whatever reason,.. it isn't listed as an option for the P5 at Rockauto,... it is listed under the regular 2.0 l protege. (Their is no installation issues for the P5)

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