Why the sudden poor running of the engine?

That is what I'm sitting here wondering.

How many miles are on the car?

That was my thought. Time for the OP to buy a lottery ticket.

OP. Don't simply reset the cam timing without checking and dealing with the tensioner. It should be a ratcheting tensioner and will have to be reset.

Recap- I have no idea why it all of a sudden started running poorly. While checking various things I decided to check the timing chain and it looks just fine, has tension, no broken or flapping parts. The timing showed 20 degrees off which shocked me because it ran afterwards, albeit poorly. At the suggestion of another poster that the timing pointer may just be wrong I checked the IP timing and found it was also offset by the same 20 degrees. So now I'm supposing the timing didn't jump at all and there is some other explanation for the sudden change in operation. Next step is checking the lift pump pressure and compression.

Check the movement and operation of the dampers in the intake manifold.

That was one of the first things I checked. I pulled the crossover tube and started it up to eliminate the flaps and EGR valve as a potential problem. It ran exactly the same.

A distant memory for me is that the timing spec for the engine is something like 14 deg ATDC. +5 or so deg may just be chain stretch.

Bad fuel.

^x2

Did you refuel shortly before it happened?

Nope. This was a long distance trip and I had fueled up the day before and gone at least five hundred miles before it started. Thinking that maybe I had sucked some goo off of the bottom of the tank I changed the spin on fuel filter and checked the primary filter on the next fill up.

A few thoughts
 

Sudden air leaks on these lines is common.
http://www.peachparts.com/shopforum/mercedes-parts-reference-library/192082-1995-e300-d-plastic-injection-pump-lines-om606-910-a.html

Delivery valve seal or O-ring failure is also common.
http://www.peachparts.com/shopforum/general-information/173991-om60_series-ip-delivery-valve-reseal.html

Warning ALL Diesel Owners
http://www.peachparts.com/shopforum/diesel-discussion/309367-warning-all-diesel-owners.html#post2841158

Bad smelling fuel, what to do
http://www.peachparts.com/shopforum/diesel-discussion/94728-bad-smelling-fuel-gag-gasp-choke.html

Algae/Fungus fixation...
Algae/Fungus fixation... - PeachParts Mercedes ShopForum

Biobor, what is it, why do I need it???
Biobor, what is it, why do I need it??? - PeachParts Mercedes ShopForum

Filters, Fungus, Biocide, etc.
Filters, Fungus, Biocide, etc. - PeachParts Mercedes ShopForum

Algae Clogged Filter Pic StarTron WORKS !
Algae Clogged Filter Pic StarTron WORKS ! - PeachParts Mercedes ShopForum



I hope it has nothing to do with this thread.
http://www.peachparts.com/shopforum/diesel-discussion/229331-vacuum-pump-rebuild-thread.html#post1927867


.

That is the injection timing - the cam timing is 0 degrees.

In the course of earlier troubleshooting I ran the car from a jug of fuel to bypass the tank, the fuel in it, the tank screen, and the supply lines. Then ran some diesel purge through it and that didn't help. Over the weekend I rigged up a test pipe in order to perform the lift pump volume and pressure tests and the pump is working well above specifications. At this point I am confident there is no supply side fuel problem and am very happy that I ran the tests instead of ordering a lift pump and relief valve that I didn't need.

I have the splined delivery valve socket on order and when that gets here I'll check, clean, and replace the seals on those.

Also on the agenda is seeing if I can make the injector adapter from my compression tester fit by pulling the valve cover and removing the injector and the well around it.

In the meantime my girlfriend has been nice enough to let me borrow her BMW M Roadster. Not a very practical car but a blast to drive. My daughter has striclty prohibited me from pressing the 'fun button' a.k.a. the button that disables the automatic skid control.

Got any pictures?

Not handy, it's 2000 in Imola red. The one in this ad M Roadster Buyers Guide - Sale Listings - 2001 BMW M Roadster - Imola Red 2 over Imola Red & Black Nappa looks just like it.