For what it's worth, Haynes lists all 616s as 24 BTDC.

I have an original German manual that lists the 240D as 28 BTDC, but that might be a eurospec car? That manual also isn't clesr if that is a spec for a w-115 or a w-123 car. If the concensus here is that 24 BTDC is the spec it should be set to, I have no problem pulling the pump and resetting it.
However, the car ran very well at 28 for some time before this issue developed.
I have an innate mistrust of Haynes manuals.

__________________
1968 230S Automatic, Elfenbein
1975 O309D Executive Westfalia Camper Bus, Blau/ Weiss
1972 280SEL 4,5 Dunkelrot
1966 VW Type 34 "Grosser" Karmann-Ghia
1963 VW 1500 Variant Pearlweiss
1969 VW Variant Automatic, Perugruen
1971 VW Squareback Automatic, Clementine Orange
2001 E320 4Matic Wagon- Our belated welcome to the 21st century! Polar White
1973 280SEL 4,5 Sliding Roof "The Bomb", Dunkelblau.

A 4 degree difference probably isn't going to explain what you seeing anyway.

Well, for 4 degrees, you probably wouldn't have to pull it.

But, I agree with Craig. It probably is not the issue. These engines can start and run with the timing off by 360°. Ask Pete Burton about that.

No possibility of you being off by 360°.........correct??

We're running out of ideas...............

I've got injector nozzles on the way. I'll start there and report back. And no, I'm not off by 360 degrees.





Well, the CAR isn't, anyways.

__________________
1968 230S Automatic, Elfenbein
1975 O309D Executive Westfalia Camper Bus, Blau/ Weiss
1972 280SEL 4,5 Dunkelrot
1966 VW Type 34 "Grosser" Karmann-Ghia
1963 VW 1500 Variant Pearlweiss
1969 VW Variant Automatic, Perugruen
1971 VW Squareback Automatic, Clementine Orange
2001 E320 4Matic Wagon- Our belated welcome to the 21st century! Polar White
1973 280SEL 4,5 Sliding Roof "The Bomb", Dunkelblau.

Well, still no go. I've made some progress (sort of) but I'm still battling a problem.
I installed new injector nozzles, and checked the prechambers for plugging by turning the engine over and watching for a "puff". It puffed so hard on one short shot of the key that it shot all four injector sealing rings that I forgot to remove out of the holes, never to be seen again, so the prechambers aren't plugged. Installed new injector nozzles and new seals. Replaced the "O" ring for the main fuel filter. Decided to re- time the pump at 24 BTDC. Checked to make sure all lines were good. I have fuel gravity flowing very well out of the metal fuel line in the engine compartment.
Well, after a good hour of bleeding and trying to get this thing to start- it finally did! But, it ran like total garbage at 24 BTDC- Missing, sputtering, lots of smoke. Put it in "D" and it would smooth out, but the injectors- a couple of them- would intermittently NAIL really loud at idle.
But the POS would start EASILY every time!
So, I went back and adjusted the pump to 28 BTDC where it ran like gangbusters before, even puffs out the exhaust, very little smoke, great accelleration, etc.
Now it won't start AT ALL. :wtf:

Can something on the timer or in the IP be off?

__________________
1968 230S Automatic, Elfenbein
1975 O309D Executive Westfalia Camper Bus, Blau/ Weiss
1972 280SEL 4,5 Dunkelrot
1966 VW Type 34 "Grosser" Karmann-Ghia
1963 VW 1500 Variant Pearlweiss
1969 VW Variant Automatic, Perugruen
1971 VW Squareback Automatic, Clementine Orange
2001 E320 4Matic Wagon- Our belated welcome to the 21st century! Polar White
1973 280SEL 4,5 Sliding Roof "The Bomb", Dunkelblau.

If it started easily at 24°BTDC, you've basically got no choice here.

Reset to 24°BTDC........which is the spec........and then we'll deal with the other issues once it's running.

Actually, I pulled the IP and set it to 26BTDC, bled the bejeezus out of the system again, and now it starts easily and runs well, with just a bit of excess smoke.
We'll see what happens in the AM.

__________________
1968 230S Automatic, Elfenbein
1975 O309D Executive Westfalia Camper Bus, Blau/ Weiss
1972 280SEL 4,5 Dunkelrot
1966 VW Type 34 "Grosser" Karmann-Ghia
1963 VW 1500 Variant Pearlweiss
1969 VW Variant Automatic, Perugruen
1971 VW Squareback Automatic, Clementine Orange
2001 E320 4Matic Wagon- Our belated welcome to the 21st century! Polar White
1973 280SEL 4,5 Sliding Roof "The Bomb", Dunkelblau.

Be real interesting if the 4° advance prevents the start........and the proper setting enables it.........

I would be swearing like a trooper about now. Generally I do not swear at all. Even though you are a proffesional I would lay off it for a few days. Sometimes we just have to get a grip on things. Perspective if you wish. About time to mount a fuel pressure gauge in the line with a T? You seem on the verge of having to separate supply from pump absolutly anyways.In a way you already have. Before it was only an intermittent problem kind of. Now it has developed into a nasty intermittent it seems. Signifigant to some extent that engine does not like 24 degrees nearly as much as 28 degrees But why? Really other than for fine tunning purposes it should not be that pronounced in my opinion. You stated engine runs like crap at 24 degrees but 24 degrees indicated by drip or welling might be vastly different with pump under stress from dynamic loading from the timing wheel inward. Your situation is almost starting to leave me with a cold feeling. There was some history with a faulty coupling injection pump to timing wheel awhile ago. Do not remember if he set his primary timing either but think he did. It would not start either and pump was turning I believe. You are already thinking this plus might just explain your funny unusual timing sensitivity problem as well. I do not really want to indicate possible endless paths on the fear of you turning up at my door to shoot me. I base this on what I would do if the situation was reversed. Just other things to consider. There are clues here, it's just to make sense of them. One was the nailing I believe. I should ask my wife for the diffinative answer but find it impossible to live with her when she knows she almost always turns out right.

Barry, I have one of those wives, too.
About that coupler- Just for the halibut I grabbed a different coupler off of an early 240D IP in my parts stash and used that, too, the last time I R&R'd the pump to set the initial timing. I mean, why not?
Like I said, we'll see what happens in the AM. I've seen a lot of wierd IP problems on German diesels, but mainly on 1980s VWs. Benz pumps are pretty much bulletproof in my past experience, but you never know.... I'm wondering if I knocked some crap loose in the pump, or MAYBE the O ring in the main filter housing was the culprit. It looked fine, and seemed to seal fine, but that was the ONE thing that can cause immediate fuel drain back to the tank, which is exactly what this was acting like.
We'll see. This thing has been fixed- for a day or two- before.

__________________
1968 230S Automatic, Elfenbein
1975 O309D Executive Westfalia Camper Bus, Blau/ Weiss
1972 280SEL 4,5 Dunkelrot
1966 VW Type 34 "Grosser" Karmann-Ghia
1963 VW 1500 Variant Pearlweiss
1969 VW Variant Automatic, Perugruen
1971 VW Squareback Automatic, Clementine Orange
2001 E320 4Matic Wagon- Our belated welcome to the 21st century! Polar White
1973 280SEL 4,5 Sliding Roof "The Bomb", Dunkelblau.

It could be a really sensitive pump. BUT- it started and ran just fine for months and months at 28 before.
Hmmmmmmmmmmmmmmmmmmmmmmmm.

__________________
1968 230S Automatic, Elfenbein
1975 O309D Executive Westfalia Camper Bus, Blau/ Weiss
1972 280SEL 4,5 Dunkelrot
1966 VW Type 34 "Grosser" Karmann-Ghia
1963 VW 1500 Variant Pearlweiss
1969 VW Variant Automatic, Perugruen
1971 VW Squareback Automatic, Clementine Orange
2001 E320 4Matic Wagon- Our belated welcome to the 21st century! Polar White
1973 280SEL 4,5 Sliding Roof "The Bomb", Dunkelblau.

Barry might be onto something..............

If it ran at 28 and now it will barely run at 24...........maybe dial it back to 20 and see what it does.

Maybe there is something slipping..........somewhere..........

Well, it started this morning on the second shot. Not bad. Very little smoke, ran great. Ran a half dozen little errands all over town, started and ran great every time. Decided to use it to take the wheels from my '66 VW Type 34 Karmann Ghia to get tires today. Loaded the wheels in the trunk.
Hit the key- Crank crank crankity crank crank crank. Smoke out the TP, but not even a sputter from the engine. It was the first hot afternoon, and the car had been sitting for several hours. Strange, but there was NO glow plug action. I took the wife's 300TDT and did the tire thing. About an hour later, I went to try it again. This time, the glow plug light came on for about five seconds. It tried. I tried it again, and it started- but with a really bad misfire for several seconds. I went to move it about an hour later, and it took about six tries, but it started, and ran fine this time. The glowplug action by the light in the dash was all over the lot- Sometimes it wouldn't come on; sometimes it would for several seconds.
NOW I'm wondering if I have a secondary problem in the glow system- either a failing glowplug, or a heat sensor that's "off".
Anyone had any experience with THIS sort of symptom?
For the first time in my life, there's a Mercedes Diesel I hate.

__________________
1968 230S Automatic, Elfenbein
1975 O309D Executive Westfalia Camper Bus, Blau/ Weiss
1972 280SEL 4,5 Dunkelrot
1966 VW Type 34 "Grosser" Karmann-Ghia
1963 VW 1500 Variant Pearlweiss
1969 VW Variant Automatic, Perugruen
1971 VW Squareback Automatic, Clementine Orange
2001 E320 4Matic Wagon- Our belated welcome to the 21st century! Polar White
1973 280SEL 4,5 Sliding Roof "The Bomb", Dunkelblau.

Yep, sometimes it would not come on until you cycle the key six times........then it would come on. Trying to start it at 30°F. was a real challenge. Crank and crank and crank until it crawls up to an idle. The slightest hint of fuel from your right foot and you're toast.

Two bad glow plugs.

Now, understand that one plug was probably bad for awhile and you have a rough start because of it........now with two down.........it probably won't start.