1.6L CY engine code EGR/vac lines

[as4k]

Looking for some help on a project car I acquired. Its a 1981 Audi 4000 turbo diesel. It was originally an emissions testing car from Audi, so its a bit of an odd/rare car. I acquired the car with the long block installed but everything else in boxes. The car needs put back together, which I'm in the middle of.
There arent a whole lot of diagrams out there for a few things. This car has an EGR and also some odd contraption that has a bracket on top of the injection pump. It has 3 vac ports and also an arm that connects to a ball on the injection pump. I have no clue what this is or what vac lines hook up to it. There is also a coolant sensor with 2 vac ports. I cannot find where the vac lines for this go to/come from.
Anyone here familiar or have some engine bay photos? I've been searching pretty much every night and its tough to find info. Putting this thing back together is like doing a puzzle without a box. Its fun, but dang so weird because its so uncommon.

Hope these photos link ok

Few photos of the car itself.

 

[d24tdi]

Given the unique history of your particular car as an engineering mule, I can understand why you might want to try to get the experimental EGR system hooked up and working. But... the best course of action is probably to not do that. If it were me I would just eliminate any EGR-related components (save them for historical display if you wish, but on a shelf in your garage, not on the car ). They will not succeed in doing much if any good and will be a challenge to get working and maintain, overall a liability with no benefit.

Some other diesels from this era (late OM617 Mercedes and D24T Volvo among others) used mechanically controlled EGR systems similar in concept to what you are dealing with on this car. They used a system of electrical switches on the throttle lever that acted at idle and WOT, as well as a vacuum modulator on the IP throttle lever and a thermo vacuum switch, plus various electrical vacuum valves and regulators, all operating a vacuum controlled EGR valve at the end of the chain. The system on your car appears to be designed to work in a similar way. That is what the linkage on the IP throttle lever is for, for example. (Cool to see the custom made ball and socket ends on that btw!)

Problem is, these systems were extremely crude and primitive at best -- when they were NEW, and on factory-built cars. These 40+ years later now, you can assume any or every component might be malfunctioning. You will end up not opening the EGR valve when it should, or opening it when it shouldn't, etc. And since the system is fully mechanical, it has no feedback control, nor any diagnostic capability, two things that are vital to making systems like this work (and integral to modern computer controlled systems such as found on a TDI etc). You could go all-out with installing monitoring devices and run the car on the road under various conditions to see if the system worked as it should.... but even if you succeeded in that, it could malfunction the next day and you'd never know it except for by the driveability symptoms. No MIL to light, etc.

On top of that, sourcing replacement components would be all but impossible. That is the case for the EGR systems on the old Volvos and Benzes and the like, and those are factory-installed systems. Your one-off setup would be even more of a challenge unless you wanted to homebrew replacement parts.... and then that probably defeats the preservation purpose, eh?

On the EGR-equipped Volvos I have owned, the best move is to simply unplug and remove all the primitive EGR stuff. That prevents the problems that come from improper EGR operation (power loss, smoke, intake manifold clogging). In cases where appearance matters, you can source non-EGR exhaust and intake manifolds to eliminate the valve and plumbing also. In your case it would probably be easy to do the same from non-EGR 1.6TD engines.

Note that I am saying this as someone who is personally no fan of emissions deletes or the folks who tend to do them, on modern rigs. But on this ancient caveman-technology emissions stuff it is unfortunately the only realistic way unless you want to devote massive resources to making them work.

Cool car either way. Do you know where it has been all these years and the story of how it escaped from Audi R&D's grip?

 

[as4k]

Appreciate the reply! In all honesty I'd be fine without any of it. Is there any harm in leaving the EGR pipe from the intake to exhaust manifold, but plugging the vac port in back? Or is the correct way to make block off plates? In terms of the mechanical piece on the injection pump bracket, I'd gladly do without it. I honestly didnt quite know what it was, but suspected EGR related when I eventually found a few vacuum diagrams for a gas injection car. I just wasnt sure if leaving the pipe there caused any harm.
Interesting history on this car, and actually I'm doing more research on it, so more to come. This car showed up at our club area at the Import Kit/Replicar Nationals in 2010, but on a dolly. I think I remember who owned it then, but he is no longer alive. The car had a hole in the block, so not running, but whatever happened looked "fresh" so not long prior. My friend in Georgia bought the car and it was there ever since I acquired it at the end of July. A new (rebuilt) CY engine block was sourced, original head rebuilt, and all sorts of parts ordered, but never put together. Injection pump was done by Giles in Canada. The car arrived with crates full of stuff from the engine bay. Some stuff original, some VW specific parts (which I dont need), and nuts, bolts, etc. Finding where everything goes has been fun, and parts ordering/finding is always fun with ANY older Audi.
In terms of Audi using it for emissions testing, I'm waiting on more info. I have the original maintenance booklet. In one month the car did 6000 miles. Pretty wild. I'll post up more pics and information as I get it. Appreciate any help on if I can just leave the EGR pipe there or not

 

[d24tdi]

Is there any harm in leaving the EGR pipe from the intake to exhaust manifold, but plugging the vac port in back? Or is the correct way to make block off plates?

Nope, that will work just fine for defeating the EGR system. Disconnecting the vacuum line will just leave the valve closed at all times. So, provided the valve is physically intact and not leaking (you can take it off and check/test if you want to be sure), that will have the effect of making it as if the EGR system is not there. The valve and pipe will be present but will have no functional effect.

If you want to be extra certain you could replace one of the steel gaskets with a piece of sheetmetal as a blockoff. That way you physically prevent exhaust gas flow but keep the underhood appearance original without having to use cheesy blockoff plates.

Glad you are getting it back on the road! Would be fun to know more about the history if you get more info.

 

[as4k]

Ok, that is good news. This will clean the engine bay up just a bit with that one piece removed. Knowing that I can keep the EGR pipe is good. This actually solves the vacuum line mystery (since I dont have to worry about it now!). Now its just waiting for the turbo to get checked out, etc, put the radiators in, and drain the fuel thats in the tank. Once I know the engine runs I can work on other things. Here are more photos for now. The first 4 are from 2010 when I first saw and learned about this car.

Engine back in. L to R...Me, my friend Zach (who is the diesel guru), and Tyler.

Wild dual radiator setup for "warm climate" vehicles. I've seen 2 radiators, but not one with 2 fans!

Touchup paint for a few areas

 

[d24tdi]

That is really cool, a piece of history.

Another thing I think is true but someone will correct me on if not: I believe 1982 was the first year for availability of turbo diesel engines in the US (in any VW vehicle). Maybe it wasn't even until 1983. Note the badge on the trunklid only says "diesel" not "turbo diesel". So this 1981 car must have been a testing mule for the TD engine and maybe also for its emission controls. I have never been up close with a Quantum TD but wonder if any of these EGR systems made their way into production on those cars? The rest of the setup (turbo, manifolds, exhaust) look similar to a Quantum TD so at least that may be a source of parts if you need it.

As a matter of fact I am not sure you could even get any diesel engine (turbo or not) in a 4000 until 1982 from what I am seeing. And also judging from your photo of the warranty book which mentions a 5000 diesel but no 4000 diesel. So yet another way in which this is unique.

It is surprising that someone was obviously eventually able to register it for regular civilian road use and put some miles on it, at least judging by the oil leaks and general wear and tear. Almost certain that this engine would not have been emissions certified for 1981 and was probably only operating under a manufactuer testing exemption so someone must have found a loophole or done something sneaky. What does the odometer say?

Clearly they wanted it to stay cool with the TD engine, I never knew about the possibility of double radiators in these.

All in all, a one of a kind vehicle, glad that it is going to see the road again.

 

[as4k]

I know of another 4k turbo diesel, but believe its an 83. From a badging perspective I didnt even think of the "turbo" being missing.
Funny you mention the Quantum. A friend saw a listing on fb for a maroon Quantum turbo diesel 5spd in CA. Got some engine bay shots and its pretty close to what I have, minus the weird EGR stuff at the injection pump bracket.
I'm really hoping to procure some concrete info on this car! For its age the car is in good shape. Its also Helios Blue Metallic with no sunroof, which a lot of older Audi's had. Its also a non AC car, which is a bit surprising.
I'm pretty excited. I'll plug my instagram (mikesvirtualgarage) and YouTube (Mike's Virtual Garage) since there will be content on this soon.
I def think the dual radiators are overkill, but I'm keeping it for originality sake. The car came with a brand new Behr radiator if I ever wanted to switch to the conventional single rad/dual fan set up.

 

[Steve Addy]

I know of another 4k turbo diesel, but believe its an 83. From a badging perspective I didnt even think of the "turbo" being missing.
Funny you mention the Quantum. A friend saw a listing on fb for a maroon Quantum turbo diesel 5spd in CA. Got some engine bay shots and its pretty close to what I have, minus the weird EGR stuff at the injection pump bracket.
I'm really hoping to procure some concrete info on this car! For its age the car is in good shape. Its also Helios Blue Metallic with no sunroof, which a lot of older Audi's had. Its also a non AC car, which is a bit surprising.
I'm pretty excited. I'll plug my instagram (mikesvirtualgarage) and YouTube (Mike's Virtual Garage) since there will be content on this soon.
I def think the dual radiators are overkill, but I'm keeping it for originality sake. The car came with a brand new Behr radiator if I ever wanted to switch to the conventional single rad/dual fan set up.

The B2 quantum is identical to a 4000 turbo diesel in the front end inner structure, subframe support etc, but with a different rear axle assembly. The 4000 used a different beam with a panhard rod whereas the Quantum (Passat) used VW's favorite beam axle assembly that would become typical for everything else FWD they built.

Nice to see a 4000 TD that unique, glad you got it!

Steve

 

[as4k]

Yikes, been a minute. Figure I owe whoever reads this an update (its been almost a year since my last post).
A lot has happened and I'll sum things up. I got a lot of stuff working.
Rear power window motors torn down, clean, lubed up and front window regulators just needed some lube. Now all 4 power windows work great. Power locks werent working right. Car needed a new vacuum pump and a few pin hole leaks in hardlines under the carpet fixed. Power locks (and trunk) work as they should now.
Installed H1/H4 quads, which should be a nice upgrade from the sealed beams.
Installed front seats from an 84 Audi 4000 LE (these had nice sport seats)
Added some good rebuilt calipers up front with new pads and rotors. Rear drums and wheel cylinders looked amazing so I left them alone. Installed new rear wheel bearings at least. Fresh brake fluid and bleed all around.
Main radiator recored (which I wanted ALL summer for), and I actually found a NOS secondary radiator on ebay.
Got some new injectors installed
New starter
Engine bay pretty much all put back together. After some fiddling with bleeding the injectors the car actually ran, which I was happy to see, hear, and smell. This was many months ago though. I got it running before sending the main radiator out for fixing. Car idled great and I got it up to temp. No drama or issues there. I had not driven it yet though because at that time the brakes werent the best.

So where are we?
I've gotten more parts in, mainly for a suspension refresh, which will happen when I know the car drives and stops properly.
Before I knew there was an issue with the brakes I got the car running and wanted to see if it would move. It moved but the brake pedal was really hard. Add to that the clutch pedal engagement was SUPER high, which actually made the car undrivable. Car stalled many times on my street before opting to push it back up the driveway and into the garage.
Having owned only another cable clutch VAG car and never having to mess with it, its all new for me. Looking at the Bentley I notice the release lever needs to be a certain distance from the bracket where the cable is held. I paid no attention to this but also didnt touch it. I assume this is my issue because no matter how I adjust the cable there is basically zero free play at the pedal. I'll work on getting the cable off and adjusting the lever.
Other issue is the brakes. I pulled the vac hose off the brake booster and really didnt feel much suction there. The pump on this car is the smaller, more round one with only 1 vac port on the top. No idea if its the same one that came on the car originally, but based on the original hose I took off, it looks like it. I took the vac pump out and figured there may be an issue here. Mistakes were made when I was trying to get the hose off of the pump. I ended up snapping the plastic piece on top off. That was bad news, but I found replacement tops with seals and such. After weeks it finally came in the mail today. To continue the punishment the top plate is slightly a different shape and the holes dont all line up, so I just extended them so it "worked". At this point I didnt put any new seals in and just tossed the pump in. Not a lot of vacuum at all, so my next move is to replace the 3 seals and see where that gets me. If not guess I'm looking at a new pump? I did try installing one of the larger ones, but it wont really fit right right turbo feed line there and thats a pain to move.

OH, one last thing for now. I went through a few months to even title this thing. Since Georgia doesnt require a title for anything older than 1985 that made things more challenging for me in Indiana. I ended up having to get a court order to acquire a title. Got all that done and registered the car with a period correct 1981 plate. Whats interesting is I do have the original New Jersey title from 1983 in my hands as well. Neat relic.

I'm dying to drive this thing. I'm REALLY hoping I dont have a bad brake booster because those seem tough to find. If anyone has BTDT on this, I'm all ears. Could be a bad master? Not sure.

Some random photos over the months for those that have been kind enough to read this.

The belly pan isnt pictured but I pulled it out from under the car for cleaning. I found 2 pieces of the original block on top. No idea how they survived me moving stuff around.