I too am curious about the CDR valve. My intake looks terrible.
I really appreciate all the advice. I started it this morning and the white smoke was better at idle. I checked with a test light and I am getting power to the fast idle solenoid but I think I need to adjust it more because it pretty much does nothing to bring up the rpm. If I push the plunger on the solenoid all the way with the engine running the rpm does not come up. That might be part of my issue that the cold advance is working and the rpm was not coming up to match it? I drove it to work again and the black smoke is at least half what it was at all speeds and loads so I am happy with how it's running. Should I install a new CDR valve at some point? Does it need the CDR valve to allow the engine to suck in the crankcase vapors? What about just running the tube from the oil fill neck down below the frame like a traditional draft tube that a semi runs and deleting the valve and tubes that run to the intake? That is how I have my 6.0L powerstroke setup. Way cleaner in the intake without all that oily crap going back in there mixing with the egr fumes.
It sounds like I can just unplug the vacuum to the egr like you did and it will be "deleted" that way until I remove the intake some day and change out hard parts. I did notice that when I went from a non-working vacuum pump to a working one the engine tone at idle changed. Not sure why.
I too am curious about the CDR valve. My intake looks terrible.
I've been told an additive helps with a lot of things. I've had a couple of my shops tell me the run a bottle in every tank. I don't have the attention span to do that, nor the wallet.
Todays ultra low sulfur diesel is horrible for fuel systems. They have taken out all of the lubricity in the fuel so it is really hard on the whole system since it uses the fuel to lubricate everything it runs through. I always run an additive. If I have access to it I run any kind of petroleum based oil in my tank to help it out. On my powerstroke and now my blazer also. Sometimes I get waste transformer oil(WTO) from work which is like 10 weight hyd oil and burns very well. I'll run a 5 gallon bucket to a 28 gallon tank of diesel. I have about 6-5 gallon buckets of clean used hyd oil at home now and I run a bucket of that to each tank of fuel on my powerstroke. I throw new atf in there also if I get some new stuff that isn't needed for anything else. I will prob start running the Stanadyne brand additive in my blazer since it has a Stanadyne pump. I've heard good things about it. I use Diesel Power Service or Howe's in our fleet at work. On anything newer with either a common rail injection system or a DPF you have to be careful and run the correct additive for the system. Common rail is a pretty tight tolerance system so I don't like to throw any extra weird crap in with those systems just regular additives. On the dpf systems(07 and newer) it needs to be an additive approved for a dpf.
I will research the CDR valve and most likely convert it to a standard draft tube and just cap off the ports on the intake that it goes to now.

No whistle. If I have the engine running and pull the vacuum line off the top of the pump the engine changes it's sound. Possibly egr related or something. I'm not worried about it I was just curious.You will have deleted the function, but you will still have the valve plugging your intake manifold. The non-emissions j-code intakes have noticeably larger air passages. Ditto for the 6.5 intakes like I'm running.
The vacuum pump can generate quite a whistle if it's not hooked up. Not sure if that's what you're dealing with.
No whistle. If I have the engine running and pull the vacuum line off the top of the pump the engine changes it's sound. Possibly egr related or something. I'm not worried about it I was just curious.
Yeah one side of the tee goes to the HVAC and the other to the egr and some other engine stuff. Not sure what. I did have to egr vacuum plugged off before I did the pump but after changing the pump I hooked it back up to make sure that wasn't affecting my smoking/running issues.I thought you said EGR was already unhooked. Interesting. When I unhook my pump I get an obnoxious whistle on the pump end. You can't have much hooked up to the pump. Should just be emissions and HVAC if you have A/C. No tranny vacuum line unless you have a TH400 (which wasn't offered in civilian blazers).
Yeah one side of the tee goes to the HVAC and the other to the egr and some other engine stuff. Not sure what. I did have to egr vacuum plugged off before I did the pump but after changing the pump I hooked it back up to make sure that wasn't affecting my smoking/running issues.
I do have a gallon of Lucas Fuel additive. I usually run it in my gasser's every couple of tanks. It says it's good for diesel use too. Would that be efficient enough?

No you won't notice anything. It will just add some of the sulfur back into the fuel which is what keeps injectors and pumps happy and well lubed. Some of the additives you will get a little better mileage and maybe notice a slight difference but I'm never consistent enough to notice. I used to run this stuff called "Drew's Brew" that I read about on another site. It is 8 oz of Marvel Mystery oil and 16 oz of Diesel Power Service I believe and you run it in every tank and it cleans out your fuel system and helps it run better. I did notice a mileage increase with it and maybe a slightly quieter/smoother running engine but you gotta buy and mix it yourself and consistently run it every tank or it doesn't work right.1 quart per 34 gallon tank?
Will I notice any changes in the way it runs?