Yes.... They are A LOT different.

That component would be #126 on his car. That is the Boost switchover valve.

__________________
AJ

1985 300D (SOLD)

As per Delivery Valve's instructions, I plugged up vacuum lines 63b and after #81. Transmission shifts smoothly as before so i removed the rest of the lines. However I can't find the line to the #71, because I'm not sure where #71 is. Its below the EGR valve? All runs well, no noticeable difference in performance though, but ticking and sticky tach is gone.

SnookWhaler, your shiny engine compartment is making me jealous.

__________________
1985 300TD Turbo Diesel Wagon
273,000 miles

#71 runs from the ARV over to the middle of that switchover valve #81.

The ARV is over by the EGR valve and below.

__________________
AJ

1985 300D (SOLD)

I believe this diagram can be used for my 1983 300td. Can someone confirm that?

I like the way elimination of the EGR cleans up access in the engine compartment. This is my 1983. I also totally removed the thermo-vac switch and replaced it with a simple brass pipe plug.

Note that normally the EGR only operates during cold start to warmup thus eliminating a major source of unburned hydrocarbons. That's why the EGR valve is controlled by the thermo-vac sensor. It's effectiveness for a diesel has always been questionable.

Also, be aware that if you have to emission-test your car and your state also requires a visual inspection you will flunk without the EGR valve physically in place no matter how clean your emissions.

Attached Thumbnails

 

Wrong on all points. Want to try again?

No, that's for a later engine, it has a few items not found on your car.

https://www.youtube.com/watch?v=qaubu8OcWR8

The above should help.

__________________
83 SD

84 CD

Watch out, we got a bad ass over here.

__________________
CENSORED due to not family friendly words

Well, the egr valve does not open on a cold engine, only hot.

As far as how effective it is, can't prove anything.

Yet allowing hot carbon monoxide mixed with soot into the intake, well, that's just a detriment to performance. Then after many years will clog the intake, further reducing performance.

Internal combustion engines operate at their best when fed cold oxygen. Ignition is a form of fire. Fire has a triangle of components, fuel (diesel), ignition (compression) and oxygen. Remove any of those and you put out the fire (combustion).

Attached Thumbnails

 

__________________
83 SD

84 CD

The EGR opens on a warm engine. All the more reason to eliminate it, particularly with a diesel.

Mxfrank was right. Could have been a little smoother but right anyway.

The purpose of EGR is to reduce NOx emissions. It's effectiveness can be measured with a gas tester.

The effect of adding unburnable components to the intake charge isn't very significant with a diesel, especially if it's equipped with something like Mercedes' EDS system. The reason is that Diesels operate with excess air in most conditions. All EGR does is move the combustion mix closer to stochiometric, which is to say, enough air for combustion with less excess. With electronic controls like EDS, the EGR valve will only be open under light load conditions, but it will shut under high loads. In other words, when you are cruising along at steady speed, you will have maximum EGR, but when you press the pedal and need power, it goes away. If your car is working well, then you're not going to see much effect on performance or fuel economy by blocking off EGR. And it certainly doesn't "put out the fire".

The issue of clogging manifolds is more tangible. But if the car is running well, cleaning the manifold every 150-200K miles will be the worst of it. At that, it's more asthetic than real. Better to have a clogged manifold than clogged lungs, anyway.

Yes, I've seen photos of obstructed manifolds, and heard tales of rapid build up of soot, but my bet is that there's another, more serious problem involved with these extreme problems...like miscalibrated injectors, a leaky turbo seal, partially blocked turbo return line, or damage to the vapor separator.

To sum up, there's no valid reason to remove EGR. The downside? If an increase in NOx emissions doesn't matter to you, the potential of being fined by EPA or CARB should.

The vehicle in question does not have any electronic controls, no EDS.

The only mis-calibration is a weak injector spring or clogged injector (pintle). The latter caused by soot getting into the intake.

These older cars egr system operates as in the previous post, temp only.

If you would like better engine performance, remove the egr system, as stated before.

__________________
83 SD

84 CD

Not sure if above means the OP should remove the cabin vent & filter when discarding the EGR components. I removed the EGR on my 84 & 85 300D, and still have the cabin vent & filter. In the 1985 vacuum diagram posted, "a" is "cabin vent", which the VCV still needs (transmission shift control above I.P.). I don't recall the EGR stuff in the 84 engine being any different than 85, but both are CA cars so may differ from federal. I put Roll Guy's EGR block-off plates on one car and like it - cleaner, easier access to alternator.

Other things I did to improve the engine bays were eliminating the electric water pump (not needed, can cause a dash fire), installed 1985 tranny vacuum controls (blue moon amplifier), and 1985 CA air cleaner (frame-mounted, w/ silicone 90 deg duct to turbo).

Keep the vent line from the VCV to the inside of the cabin, this is part of the transmission shifting mechanism.

Nothing to do with the egr.

__________________
83 SD

84 CD

I've recently been working following some of the steps in this thread for my '85 300D. My car has the vacuum set up described in this picture below but does not have the California air cleaner and trap oxidizer.

I blocked off vacuum to the EGR quite a while ago, then recently (about a month ago) I took the EGR valve off for inspection and found it stuck open. I cut a piece of thin aluminum to block off the EGR opening and put it between the valve and the manifold. I also cleaned out the alda banjo bolt at the back of the manifold which turned out to be pretty dirty. None of this made a noticeable difference in how the car ran.

Last week I followed the diagram below and blocked off the lines going to the EGR vacuum convertors and switchover valves (#81 and #84). The car is running noticeably better now; boost seems to come in quicker, I think it is shifting better and, when warm, it is idling much better.

However, when cold, it is starting much rougher than it ever has. E.g. it shakes more violently at first turnover then I ever remember it doing (I've had the car for four years). It's also putting out a decent amount of smoke as it tries to get going. After about 10-15 seconds it smooths out to about what I would expect for a usual cold start for this car, i.e. a bit shaky but not concerning.

Is this just a coincidence, or could messing with the EGR vacuum components have a negative affect on cold starts?