1998 E300 td.

can anyone confirm if there is a cold start mechanism built into the fuel pump? and if so can i access it by removing the rear of the pump casing. If there is a cold start mechanism, i think it may have jammed and causing the engine the diesel knock.
Ive been at this few weeks now and cannot cure the knock at idle. This is the last item to check before i replace the pump. Also, were can i purchase the pump and pump sprocket locking tools. Ive tried Ebay and can't find any.

Regards

This IP is from a 97; is this one similar to yours?

Pelican Parts sells the Timing Locking Pin for it.

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84 300D, 82 Volvo 244Gl Diesel

Diersel 911

Yes this pump looks the same. Are these prone to internal faults as im at my wits end with this diesel knock.

Like i said ive been trying to fix this for the past 6 weeks, new fuel lines, O rings, filters, diesel purge, FSOV, lift pump, filter housing, injectors and bypassed various pipes to try and clear the air bubbles in the fuel lines.

Still knocking at idle.

There is no cold start mechanism in this pump. The internals are very, very, very simple, no adjustments aside from element quantity and this is not something that ever goes out of adjustment or needs attention.

To get these engines to run perfectly, you HAVE to get all the bubbles out of the lines. Once that's done, you have to drive for at least 100 miles before it settles back down.

As I said in the other thread, it's possible for a delivery valve holder to need re-torquing as well.

And yes, I know the bubbles are frustrating. I've been chasing a ping in the engine for weeks myself and I'm ready to redesign the whole fuel system.

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250

KarTek.

Can you tell me if these pumps are lubricated by engine oil or do they have there own oil. When I removed the lift pump, black oil spilled out of the pump casing. How do I check the oil level in the pump?

The Fuel Injection Pump is lubricated by the Crankcase Oil. However, the area for the Oil to drain back to the Engine is high enough that there there is always a pool of Oil inside of the Fuel Injection Pump.

The Used Oil that remains in the Fuel Injection pump and other places like the Oil Cooler System is one of the rasons the Oil gets Dark quick after an Oil Change.
On the 617.952 Engines there is about 1 liter of Old Oil left inside of the Engine when the Oil is drained out.

If I did not mention this; late Fuel Injection Pump Timing can cause the Nailing at Idle speed and I attempted to re-time My Fuel Injection Pump advanced several degrees beyond what Mercedes wants and found it will also nail when the Timing is too advanced.

You might remove your Valve Cover and line up the Camshaft Timing Marks (not sure where yours are maybe on the Back of the Camshaft Gear and the Front Camshaft Bearing Cap) and see what degree on the Crankshaft that the Pointer points to.

If the Valve timing is late due to Timing Chain Stretch/Gear Wear then if the Fuel Injection Pump has not been re-timed that Fuel Injection Timing is going to be late.

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84 300D, 82 Volvo 244Gl Diesel

Double check the following:
O-ring in the pre-filter basket - on my car, the sealing surface was dirty and it wasn't getting a good seal - there is supposed to be another o-ring besides the one on the incoming fuel hose connector.
Pre-filter retention bracket - gently bend the tabs down slightly so that it presses more firmly on the fuel hose coming in the top.
O-ring on the shutoff valve feed into the IP body - you have to remove the SOV to get to this. It's possible to access the SOV if you drain and remove the washer fluid bottle without having to take off the intake manifold.

Did you put on new plastic fuel hoses or just replace the o-rings on the connectors? If the hoses are brittle they might have a hair line crack. Most of the fuel delivery side of the IP operates at pressures below atmospheric so cracks in the lines don't leak, they suck air.

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The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

Diesel911

Thanks for your reply. i removed the pump from a doner vehicle today and discovered that it is lubed by the engine oil.
The crank and cams timing are bang on, the engine has only done 49000 miles so i wouldn't expect any chain stretch.

This diesel knock happened suddenly.

Engine was running perfectly smooth then went to start it one morning ( glow plug light on) and it struggled to fire up and when it did its knocked ever since.

If i retard the timing and the knock dissapears would it be safe to run the engine like that even though i haven't resolved the actual problem. I did adjust the timing a few weeks ago (rotated the the pump towards the the engine block) and the knock 99% dissapeared but the engine oil level increased (diesel leaking past rings) after a week of driving it. I adjusted the timing back to its original position and changed engine oil and filter and level is ok now.
Which way should the pump be rotated to advance or retard it?

Jay Bob

Thanks for your reply.

ive already done everything you say and more to try and resolve this bubble issue. Just going to have to quadruple check it all again tomorrow.

I could understand if the engine was slowly under performing over a period of time.
It was running purrrfect then went to start one morning and it knocked its head off and has done ever since. Only at idle and low revs otherwise it drives lovely.

Check the 2 rubber lines from the tank supply to preheater and the filter to tank return for leaks too

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech