It's not uncommon to need so much adjustment that the pump needs to be removed and reindexed. Any notion that only one or two degrees of adjustment will be needed is completely without basis, especially with 365k miles and unknown history.

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That normally happens when someone has previously removed the Fuel Injection Pump and re-inserted the Fuel Injection pump without centering the Kidney Slots in relationship to the Bolt Holes or Studs.

An other issue can be they inserted the Fuel Injection Pump at the correct Degrees and managed to bump the IP Camshaft to rotate it when the inserted the Fuel Injection Pump (the very thing the Timing/Locking Pin is supposed to prevent).

Anyway that is my opinion on it.

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84 300D, 82 Volvo 244Gl Diesel

That's a great theory. But the witness marks often tell a different story; typically, the pump hasn't moved since it left Stuttgart.

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

I adjusted the injection pump in my 84 300D just yesterday, for the first time. It was very difficult to get at 2 of the 4 nut/bolts.

The rack position sensor is in the way for the top-right nut. I had to spend a lot of time to get just the right combination of sockets and extensions to get my 3/8" socket wrench into the narrow gap where you can swing it, just aft of the sensor. I also had to jam a screwdriver against the extension to hold if for the clicks.

The aft bolt (below vac shut-off valve) was tricky because I had to swing a wrench in the small gap between the oil cooler tubes. I used a Craftsman 13 mm ratcheting box wrench that has fine clicks. I was able to loosen the bolt, barely getting the next click. But in tightening, I had to remove the wrench each time and turn the head manually for the next click, which took a long time.

I adjusted the IP on my 85 300D a month ago, and recall it being much easier. That car has an 82 engine, which doesn't have the rack position sensor. That sensor is only used for the EGR controls, which I bypassed anyway.

I never fooled with making a "drip tube", as shown in the manual. I just remove the #1 fitting on the pump. Before "start of delivery", the fuel squirts out, as you pump the primer. The "start of delivery" is where the flow gets blocked. It is a pretty sharp point, changing from squirt to nothing in ~1 deg of crank rotation. The 1 drip/sec is probably an anal spec the writers had to put in to quantify the process. I set both cars to 27.5 deg BTDC. Both were at ~24 deg BTDC as found, which is the factory spec. Both timing chains showed no stretch per the camshaft mark.

I can't say I really noticed a change in the way the engines run. Indeed, I found 3 injectors in my 84 engine were non-turbo (popped at 1600 psig), but it runs about the same now with 5 turbo injectors (1950 psig pop). Both engines shake a little at idle, and smooth out at higher rpm.

Not at all. The idea behind the drips per second is to get the Element Plunger positioned just before the Fuel Inlet/Feed Port is closed by the Element Plungers upper edge of the Helix.
This provides a spot that is always the same if you the Fuel Pressure steady during the timing.

Doing it the way you stated:
After the Port is closed the Fuel Flow you are speaking of will be stopped but it is possible someone to move the Punger Further for many degrees (especially in the Full Throttle positon) as the Fuel Flow will remain stopped until the lower edge of the Helix on the Element Plunger opens (ending injection) the Fuel Inlet/Feed Port on the Element. When Injection ends you will also get Fuel Flow.

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84 300D, 82 Volvo 244Gl Diesel

Kind of lost you. I didn't state exactly how I did it. I thought I followed the book: i.e. manual pump the "lift pump" as you slowly turn the crankshaft, until the output changes from a continuous flow to ~1 drop/sec flow. All I said was that I see a very quick change from a good flow to almost no flow in about 1 deg on the crank, so trying to count drips seems silly and I doubt the special "overflow tube" shown helps much. There are many special tools shown in the M-B manuals that are either "no longer available" or "never existed". Ever seen a cylinder-sleeve removal "self-made" tool in person? Same for the Mopars I also work on.

It was hard for me to move the crank just a little bit. I had to hit a long wrench with the palm of my hand a few times to budge it, hopefully in not more than 1 deg increments. Therefore, I can't keep pumping continuously, so tweak the crank, pump, watch the flow, repeat. Perhaps I could get more finesse on the crank by putting the wrench on the crank bolt, but been there (can't see the marks while underneath), so I wrench the p.s. pulley bolt pulley like most people do. Some here fuss about that, but it isn't their car.

My recommendation is that if you have a later IP pump with the position sensor, it it shows the factory 23-25 deg BTDC timing, better to leave it alone rather than try for the 26-28 deg some here recommend. I didn't notice a difference in performance by advancing it. It will mainly help mitigate timing chain wear over time.

You are doing it wrong, you adjust the ip, not turnk the crank?

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OBK #42

Of course you can use what ever method suits you.

I was trying to explain why the drip Method is used. The info might be useful to someone else.

And I was responding to what was said below:
"I never fooled with making a "drip tube", as shown in the manual. I just remove the #1 fitting on the pump. Before "start of delivery", the fuel squirts out, as you pump the primer. The "start of delivery" is where the flow gets blocked. It is a pretty sharp point, changing from squirt to nothing in ~1 deg of crank rotation. The 1 drip/sec is probably an anal spec the writers had to put in to quantify the process. I set both cars to 27.5 deg BTDC. Both were at ~24 deg BTDC as found, which is the factory spec."

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84 300D, 82 Volvo 244Gl Diesel

Can the timing go off that much that the IP needs to be removed and re-indexed? I have not checked or done a timing adjustment yet but I am seriously looking into it since my 85 300D is getting pretty crappy millage (around 22 mpg) with 157K on the clock. My 83 (sold to JB3) was getting 25 to 28 mpg with twice the miles and I never bothered to check the timing in it.

I have lot's of parts on order for my timing light project. Hopefully it will be successful and come to fruition.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

It's definitely possible. No way to know until you run out of adjustment. There is also a reasonable possibility that an old IP gasket won't survive an adjustment, so the IP will need to come off, anyway.

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When cryptography is outlawed, bayl bhgynjf jvyy unir cevinpl.

If the Fuel Injection Pump has not been touched since it left the Mercedes Factory try to imageine what would have to be worn out for there not to be enough adjustment to time the Fuel Injection Pump.
(Or someone at the Mercedes Factory would have had to install the Fuel Injection Pump without properly centering it.)

For Me the only thing that comes to mind is the Timing Chain or the Timing Gears would have to be in bad shape.
That would put the Valve Timing off also so the fix would either be a new Timing Chain and related Parts or on offset Woodruff Key.

If some previous owner has had the Fuel Injection Pump off then that could be the reason for you to run out of adjustment.

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84 300D, 82 Volvo 244Gl Diesel