Hello,

I have an 1983 300D.

I have been troubleshooting some transmission problems recently that are now solved. In the process, I have eliminated the vacuum to the switch over valve system (box mounted on top of valve cover) and thus the EGR valve as well.

I know people recommend disabling the EGR system, but I would like to make it operational again. I have the vacuum diagram for my model, and can physically hook it all back up. What I don't have is any explanation about how the system works and what vacuum levels I should see at various points. The switch over valve seems to control two systems:
1) the EGR and
2) Reducing (I think) the vacuum seen at the vacuum control valve (the plastic thing on top of the Injector Pump that controls the signal to the transmission.) I assume this is for smoothing up shifting or down shifting.

1) For the EGR system, there are 2 points to measure:
a) From the switch over valve to the electronic temp switch: With the engine off and cool, should the line from the switchover valve to the temp switch hold a vacuum? Mine leaks slowly. What about when hot?

b) From the other end of the temp switch to the EGR valve. Should the line from the switch to the EVR hold a vacuum? Mine doesn't at all.


2) For the vacuum control switch:
What vacuum levels should I see in the line from the switchover valve to the vacuum control switch (intake)?


Thanks
Doug

For the EGR: Do you have access to the engine manual? It has multiple diagrams of where the vacuum is being applied at various temps and throttle settings. I don't know if says how much vacuum, possibly either "some" or "none."

That's for the '83 617 w/ CA emissions, or Fed?

I do have a PDF manual and the answers are there, although not exactly clear. I will test it.
How can I tell if I have Fed or California? The manual only gives a diagram for CA starting in 1984, and mine is 1983 and seems to match the diagram in the PDF that is labeled 1981 - USA.

I should have phrased that differently, as in: did the '83 have different emissions, and based on your location in LA, is your car a CA or Fed. It does look like 84 was the odd year out.

I am guessing its CA (I am the 3rd owner and it was bough in CA), but I am not sure if there was a difference in 1983 from Fed to CA then - at least from the diagrams in the PDF. However, I do not know that with any certainty.

If anyone needs a ThermoValve I have one brand new I'm not using and would like to sell

__________________
-SpecialDelivery
1985 300CD Silver/Blue H&R Suspension (Sold, still cryin over that)
1982 300SD Silver/Blue '85 OM617 (Sold)
1982 300D - Blue/Blue (Sold)

What color is yours (temp) and how much?

Also, I am looking for working EGR valve (holds a vacuum) - fits a 300D 1983

Also, that little black nipple things with 5 nipples on one side and six on the other that connects the 3/2 switch to the rubber connector with 5 wholes. Does anyone know the name for this piece or part number?

black, i paid 50 something plus shipping, i'll send it to you for $40 shipped

__________________
-SpecialDelivery
1985 300CD Silver/Blue H&R Suspension (Sold, still cryin over that)
1982 300SD Silver/Blue '85 OM617 (Sold)
1982 300D - Blue/Blue (Sold)

Why would you want to enable the EGR? All it does is clog up the intake manifold and increase particulate emissions. It is the worst system ever put on a diesel engine.

dont quote me on this BUT i believe vacuum to the EGR should be at zero in two conditions, at idle and at wide open throttle. i don't know what the values should be inbetween those conditions.

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1981 NA 300D 310k miles