egr 101 question
 

Does the exhaust gas that's recirculated have adequate oxygen to support efficient combustion in the cylinder? I'm trying to understand how exhaust air can possibly add anything to combustion.

In a gas car at least the EGR cools (cool is a relative term inside an engine) the combustion chamber and tops of the pistons to reduce NOx emissions. On a diesel its intention is also to reduce emissions.

It "adds" nothing to the performance of the car, it cuts down your emissions for the EPA.

It reduces the performance of the car, and has the unintended consequence when combined with oil fumes from crankcase ventilation of clogging your intake system with carbon.

Since you have a 95 E300D, this thread may be of interest: http://www.peachparts.com/shopforum/diesel-discussion/219264-easy-reversible-egr-delete-95-96-97-non-turbos.html.

yup
 

Yea, I've been reading it. I blocked my egr a while ago. I've been trying everything to find out why she's still sluggish. I'm guessing here, but the only available air for the intake comes from the air filter box and the egr orifice. With egr blocked, that air isn't available. I want to add it back, but only fresh air. I'm not crazy about the way the little filter looks.

It does not add anything beneficial to the engine in my experience. The only reason they were ever installed is because the EPA has a long arm and mandated it be installed. There is no reason you would want burnt fuel in your intake. It is dirty and has little to no oxygen that is need for combustion. It can have the effect of reducing certain emissions but it also increases others. IE: reduces NoX but increases Co2, etc. It is trading one "evil" for another.

Something else is wrong with your car, a good running car you shouldn't be able to tell the difference with or without EGR. It saps like 2-3hp... Maybe. And by disabling the EGR you have not reduced the amount of air going into your engine, so there is no way to restore EGR flow without the exhaust gas if that's what you are asking.


More than likely the first 250k miles or whatever on your car with the EGR has loaded up your intake runners with crud. Removing/disabling the EGR will stop additional buildup but it won't clean out what's already in there.


You may need to pull the intake manifold off and manually clean it and get all the crud out.


Also! Did you lock the intake flap open or remove it? I think if you just unhook the EGR on a 606 the intake flap with stay shut. The flap is designed to create some vacuum to help pull in exhaust gasses at idle since diesels don't product manifold vacuum. But if its staying shut all the time you have a big air restriction at big rpms

At that mileage, maybe the cat is clogged. That was the problem with mine.

And yes, that flapper valve needs to be wired open from what I understand.

its like rebreathing in a plastic bag.All my cars I disable them

done and done and then some
 

Intake is clean as a whistle, cat removed last summer, tank screen clean, lift pump rebuilt, all new o-rings on fuel pipe connections, resonance flaps function properly, new fuel filters, new breather pipes, exhaust manifold pipes clear, delivery valve seals replaced, egr valve flap removed when egr port blocked, throttle cable adjusted, linkage moves freely, injectors rebuilt w/bosio and balanced. Starts easily, idles smooth, good mileage 28-30 with a/c. I just don't get it.

Define/quantify "sluggish."

slug
 

0-60 = 25 seconds.
Driving around northern Virginia, I have pedal to the floor a lot.
Can't get past 3500 rpm on interstate...about 80-85 mph.
Can't rev past 4200 in neutral
And to get it to shift to the next gear, I have to let off the throttle a tiny bit, then mash the pedal again.
Sux

Have you verified your timing?

That is slow....0-60 spec is 12.6 seconds.

Might be down in the Chantilly area this weekend. Maybe we could meetup and be able to confirm whether it's slow enough to be concerned about.