I have read posts about owners deleting their EGR valves and blocking off the openings with a plate and a plug.

Doesn't putting a piece of vacuum hose with a golf tee on the EGR port and vacuum supply line accomplish the same thing?

Kind of, but they can open themselves or may be partially stuck open from soot build-up. It's just cleaner and foolproof to remove it completely.

When I got my blue car, someone had attempted to "delete" the EGR with a BB in the vacuum line. They put one in right at the EGR valve, and another in the climate control line...

So it turned out the EGR valve was stuck wide open, and now also the climate control was stuck on defrost.
I have since remedied both problems.

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1982 300D (w123, "Grey Car")
1982 300D (w123, "Blue Car")
2001 Ford F150 "Clifford" (The Big Red Truck)
1997 Dodge Ram 2500 12V Cummins
1996 Dodge Ram 2500 12V Cummins
Previous Vehicles:
1995 E300D, 1980 300SD, 1992 Buick Century, 2005 Saturn Ion

Once you disconnect the vacuum line from the EGR diaphragm/actuator, the valve is now inoperative. Simply plug the one rubber line you removed with your choice of "stopper". I prefer a golf tee for obvious reasons. No need to plug the nipple on the EGR valve itself as the valve is now a "brick".....will not function. As mentioned, the valve may be stuck open, partially or fully, due to carbon/soot deposits, corrosion, etc. around the pintle or shaft. You may be able to crank the valve fully closed as there should be an adjusting nut (probably 10mm) somewhere on the valve body near the diaphragm. This nut enables adjustment of pintle travel and how far "open" the valve is to the stream of exhaust gases. Dunno how difficult access is to the adjusting nut or exhaust/intake connections on your car (fairly easy on my 240D). You could disconnect one or the other (int/exh) and try to spray some solvent in there to loosen up any deposits (also may be totally unnecessary) or just "crank it down", fully seating the pintle and completely closing the valve permanently. The adjusting nut should easily overcome any soot/carbon deposits that are present.

I have an 85 CA with the trap oxidizer. Rollguy’s bypass kit includes a plate to block off the EGR valve that would have nowhere to go without the trap.

On my 82 I put a Softair BB in the hose. I think it is 5mm. I couldn’t tell if it was plugged or not. Eventually I connected the EGR vacuum again and plumbed it to the thermo valve. No noticeable difference to me.

Anyone feel the difference between defeated EGR and stock?

I’m a little worried about my 85 being all simplified. I plumbed the vacuum like my 82 SD. It is much simpler to understand now but I worry the state will someday finger it as a gross polluter and demand I make it functional.

Probably unrealistic. I think the my state has given up on us old diesel people and expect the cars will retire themselves over time.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

Rest assured that you will not be able to make the EGR valve functional without a working EGR computer, which you are unlikely to have anyway. So rest easy, because there is nothing you can do to make your EGR functional again.

Good point. That system was really complex. I ripped out 90% of it. No idea what it did or if it even worked at all.

I’m just echoing a fear I have in my mind that the CARB Nazis will demand some kind of inspection at some point. In reality we are such a small group nobody cares about our NOX. They did force retroactive mods on big rig tractors though.

The system was something like my 82 but the thermo valve was electric. I think the EGR computer used water temperature to trigger the switchover valve going to the EGR,valve. Then there was some stuff going to the ARV that I ripped out that was related. I never figured out what the plug to the injection pump did.

Making all that work and verifying it actually worked is not in the realm of a state emissions test. But the way I’ve rigged it all up like an 82 vacuum system with the block off plates and trap bypass it won’t pas a visual equipment inspection.

I remember on my old 88 Toyota Celica the smog guy would undo the upstream side of my EGR thermo vacuum switch and pull on it with a mityvac to see if it held vacuum and see the engine rpm changed. He failed me on it once when I had a small crack on the thermo vacuum switch.

A similar thing happened on my 72:Volvo many years ago (1988). A smog man in Oakland, CA looked at my system and said something is wrong. He got out some books and there were diagrams of something that he said was missing. Most likely EGR control lines. He failed me but I think he was a new tech school grad hoping to flex his ego on a kid.

I’m just worried at some point in time somebody will say “where is all the stuff.” Probably will never happen. But still I regret gleefully throwing all that smog hardware in the trash. Had second thoughts long after it was gone.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles

I kept my parts ...... Somewhere. But this is TN so it won't matter (probably).

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85SD 240K & stopped counting painted, putting bac together. 84SD 180,000. sold to a neighbor and member here but I forget his handle. The 84 is much improved from when I had it. 85TD beginning to repair to DD status. Lots of stuff to do.

Hopefully it’ll be a non issue. I think when that day comes I’ll let the car go.

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79 300TD “Old Smokey” AKA “The Mistake” (SOLD)
82 240D stick shift 335k miles (SOLD)
82 300SD 300k miles
85 300D Turbodiesel 170k miles