Dissconnected EGR 300D 1983 - PeachParts Mercedes-Benz Forum

coachgeo · #1 12-29-2003, 07:41 PM

The EGR valve (think that is what it is) has a place for two lines (I assume vaccum?) to be attached. Niether one has a line on it.

How would this effect the engine? What is the best way to go from here when your dimes are limited?

Lycoming-8 · #2 12-30-2003, 12:08 AM

Concensus here over many posts and months is to leave it (EGR valve) the way it is. All that it really does is to recycle soot from exhaust to the intake and any oil (diesel) along with it. This then has the bad habit of forming a black plaque on the intake system, which really plays havoc with performance. The bad stuff also usually migrates down the line from the banjo bolt toward the ALDA. Also not good, as it will adversly affect how the ALDA works.

coachgeo · #3 12-30-2003, 12:25 AM

Mucho Tanx.... one less thing to worry about

Lycoming-8 · #4 12-30-2003, 12:57 AM

Another thing you might want to do is to check to see how bad the crud level is in the intake, the banjo bolt, and line to the ALDA. If messy, clean and reconnect everything. And finally.... a lot of folks here have fabricated a metal plate, without a hole, to replace the gasket between the EGR and I believe the exhaust. This makes sure that, even without a vacuum signal, no gasses leak into the intake.

BoostnBenz · #5 12-30-2003, 02:21 AM

Yes the solid plate may be the only sure way to know you've stopped it. If the EGR valve goes bad then by disconnecting the vacuum source to it you won't stop it from leaking the exhaust around, that only works on good EGR valves. The EGR valve itself only has a spot for one line, the thermo valve has two, and the EGR control box (black box on the camshaft cover) has three lines.

GottaDiesel · #6 12-30-2003, 10:25 AM

Hey boost,

I know this has been talked about like crazy... but here's my story.

I'm faced with needing 1 new switch (on valve cover) and 1 new switch lever -- about $40. -- not a big deal.

On the other hand, I have NO idea if my EGR is even good!

Soooo... a) how do I test it? (can it be tested? I don't even know)
and b) is the ONLY purpose of those switches on the valve cover for the EGR? Or do they have other purposes? I'm thinking I may rip all of it off, and not deal with it -- but I'd like to get your feel on it!

Oh, one more thing. I'm not sure I understand exactly HOW the egr works... if you have any links, or you're willing to give a quick education... that would be

Thanks and have a HAPPY NEW YEAR!

Pete

BoostnBenz · #7 12-30-2003, 10:53 AM

I've never tried to test one, but I suppose you could take off both ends and try running pressure into it, if any air comes out of it then it is bad.

Yes that is the only purpose for that whole box of switches atop of the camshaft cover.

While I haven't looked into this very much it is my taking that there is a spring pushing this valve shut, when vacuum is applied to the unit it counters the spring and begins to open which allows the gases through. If you take the EGR off and see what I seen you'd be very prone to yanking yours out. I wonder if I have a picture of that....

If you want to to keep the look and not the EGR just substitute a new gasket in on top of the other one, except this one is made out of metal like a pop can or such and doens't have a hole in it.

GottaDiesel · #8 12-30-2003, 11:00 AM

What is it that you've seen when you've yanked it out!

Come on now... no keeping me in suspense like that!

BoostnBenz · #9 12-30-2003, 11:04 AM

LOL, and that wasn't just stuck to the gasket, it went all the way down that hole to. I know it is very hard to see in the picture....

GottaDiesel · #10 12-30-2003, 11:08 AM

So you're saying that is crud that is PACKED in the hole?

What the heck?

BoostnBenz · #11 12-30-2003, 11:10 AM

Yes, compliments of the lovely EGR valve. Fortunately after cleaning all of that out with the side of a screwdriver eventually I could see the bottom and fortunately it still looked like aluminum on bottom of the intake!

GottaDiesel · #12 12-30-2003, 11:12 AM

Ok, just so I'm a bit more eduacted than I was before... what would the symptoms be if mine was either a) clogged or b) not working...

Then I'll leave you alone. lol

BoostnBenz · #13 12-30-2003, 11:26 AM

If that hole were clogged and not the intake you probably wouldn't notice much difference as it is only opening when the throttle is near wide open. The number one reason that the EGR valve removed is to keep the intake clean, then after that is for more room and better look, it probably doesn't affect power that much unless it is leaking. If it were not working correctly (leaking) you'd probably get some excessive smoke and idling problems as it is hard to add exhaust to the intake when such little air is flowing through the motor as is.

Lol, well it is no bother you can just IM (aim: boostnbenz y!: BoostnBenz) me if you want to rather than posting every couple minutes back and forth.