I think I got it! Amazing! I have enclosed a photo showing how much I moved the pump toward the engine - advancing the timing. Some black smoke initially on start-up, but it went away pretty quickly. Took it for a drive and it clearly runs better - NO PINGING/KNOCKING!

Would new nozzles cause the timing to change? That's the only thing I've really changed as far as the fuel system goes... I couldn't move the pump anymore AWAY from the engine - don't know what that means, if anything...

According to the picture - blue mark on right (pump side), and red on left (engine side), is this a big adjustment?

ryan

Attached Thumbnails

 

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

Good job.

How many miles are on the engine? If you are between 250k and 300k it might be worth rolling in a new chain.

If changing the nozzles caused this amount of change in injection timing then it is time to find a new mechanic.

__________________
Jim

Upon further review, my previous excitement may have been a little premature. I drove the car again and it is clearly smoking more - black smoke - while idling. Did I advance it too far? No pinging/knocking though...

I should add that when I checked the valves, all of the intake valves were loose, while the exhaust valves were pretty much on target. I didn't adjust them, because I didn't have my wrenches - and I was always told to adjust them a little on the loose side anyway, as they tighten up.

Would this effect things?

ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

It means that you were lucky. Had it been the other way, you would have needed to remove the pump and re-index it in order to advance the timing.

I don't usually have that kind of luck! What about the smoking issue??? Have I moved it too far? Intake valves being too loose?

ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

I liked the idea of having someone else pump the primer for you. That way you can concentrate on the actual timing part of the job.

Timing the IP correctly should not caues black smoke at idle. I have tried to follow your story but I do not remember if you had that smoke at the start of your trip or not or before changint to the Monark spray nozzles. Also were you getting that black smoke during accleration.
It might be useful to post a summary of what symptoms your car had from the point before you changed installed the Monark nozzles on up till now and also what you have checked and the results.

__________________
84 300D, 82 Volvo 244Gl Diesel

When you have it installed perfectly, the fuel will shut all the way off at 23* before top dead center. Anything else is wishful thinking and hoping and that never solves a Mercedes problem. Not that I've discovered. Also, when you remove that pump, put in a new gasket so you don't have to re-do the pump removal to stop the oil leak that is going to occur since you have already moved the pump unless the gasket was changed when the last person installed the pump incorrectly. Also, insure that the marks on the pump are in correct alignment with the ring on the pump. And if you don't know what I'm talking about, have someone else more experienced do the job for you or be on hand to guide you properly.

BenzDiesel

I changed out the nozzles as more of a 'preventative' measure than anything else - car has between 250,000 - 300,000 miles and I thought it was time to switch out the nozzles. Partly an attempt to improve gas mileage... More smoke now than before, and the pinging started about 800 miles into my trip to Ohio last week (about 1200 miles after replacing nozzles).

After adjusting pump, car does run better, as posted earlier (no pinging), but I do seem to have more smoke at idle - I don't really notice a cloud or anything upon acceleration.

I am sure I didn't adjust the pump "perfectly" so my question was more along the lines of what would cause the black smoke - 1) pump timing too far advanced, or still too far retarded, or 2) really loose valves (which I very definitely have, especially the intake valves).

I have no intention on removing the pump at this time...

Thanks for all the help.
ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

with a pump incorrectly installed and off a few degrees. The clean injectors are probably allowing more fuel to flow to the engine. Anyway, if you are not going to tackle the ip at this time, I would just drive the car if it is not pinging too badly or idling too roughly or not embarassing you with a lot of smoke when you pull in at the job. Or you could put the clogged injectors back in until you are ready to set that pump correctly so it will shut all the way off at 23* before top dead center.

BenzDiesel

Now that's a theory!!!

Ok, a recent development. I adjusted the valves this morning and re-checked the chain stretch by aligning the marks - and now it shows 5-6 degrees of stretch. I checked this 6-8 times before adjusting the pump and consistently got 3 degrees of stretch.

Does this make sense?

Should I change the chain (I have no idea when or if the chain has ever been changed - car has 275,000+ and I have owned it for 2-3 years)? I don't have the tool for reconnecting the links...

If I change the chain, what else should I consider changing at the same time?


ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

The old injector springs get weaker with time and open with less pressure. In addition over time they do not seal as well when closed. In essence shifting the timing.

__________________
81 300D Turbo 190K sold
83 300sd 319K best $500 I ever spent-daily driverw/ 2 tank WVO set up

Valve timing and injection timing are totally different concepts.

Would changing my pump timing change the timing chain stretch from 3 to 5 degrees?

Should I change the timing chain - it is now showing 5 degrees of stretch?

Plus, back to my black smoke - since this is new SINCE I timed this injection pump, I'm assuming this is unburnt fuel - is it more likely to result from too far advanced or too retarded pump timing?

ryan

__________________
RG Newell

1984 300D
1972 250
1986 560SL
1991 300CE

Well changing the pump timing is not going to change the chain stretch. That is a wear factor. How did you read the stretch? Always turning engine in the same direction? By the crank bolt?

I believe black smoke is a sign of injection being retarded. I would try marking the flanges with a pin punch so there can be no confusion. Try your car with the pump moved to between the two current marks. The mark you started with and where you landed up. If no longer pinging and smoke is gone stay there for now. Another way to look at is you want that pump as much toward the original mark if I read your marks correct. That being towards the block consistant with that pinging not being present. Half way between is a good place to try. . It may be just fine.

Really to do the stretch measuring properly you have to use the dial gauge method to be accurate. Make sure to read the postings on checking chain stretch as well. There will be lots in the archives.

Congratulations, You learnt something by tackiling it yourself. From now on it is easier. I suspect a few members are mulling over your results. I am not perfectly clear in my mind myself. If you did the timing all alone and the hand primer was leaking bad there might be a little discrepancy entered into the end results. The loss of the pinging noise does mean the pump was too advanced since it is now gone.