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83 300TD/97 E320/98 SL500
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Discussion Starter #1
I had the TD in for service on Thursday (oil+filter, main fuel filter + inline, valve adjustment, replaced leaky bypass hoses, coolant flush, transmission fluid + filter, adusted linkages) and afterwards, I'm getting strange vibes from the engine.

At idle, I can feel short shaking, almost like a cylinder is missing. It's sporadic and inconsistent. Idle speed no longer holds consistent, varying between ~550-750 rpm. About half the time, from a stop, flooring the pedal does little to motivate the car- there is quite a bit of hesitation until the revs hit ~1100. Beyond that, with about the same frequency, there seems to be a loss of power.

Starting out this morning, I let the car idle for about 5 minutes and when I started moving, revs started dropping, got rough idling despite flooring the pedal, and the engine dies and won't restart. 2 pumps of the primer pump expels all of the air from the system (??) and brings the engine to life.

Does this sound like misadjusted injector pump, or a leaky fuel system? The hand pump has been shedding some o-ring bits during pumping, and the expansion tank/vent is leaking. I can't say with certainty that these are the only leaks.

Any thoughts about what might be causing this? It has been a crappy start to a Monday...
 

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BenzWorld W126 & W201 Host
1988 420SE, 2002 C180 Kompressor, 200 ML320
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RE: Performance

If this has only happened since the service, then I would suggest the seal is bad on the main filter and is sucking air. You could just try tightening the nut on top slightly. Failing that, take it back to the garage that serviced it.
 

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83 300TD/97 E320/98 SL500
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105 Posts
Discussion Starter #3
Thanks Spanners- I'll double check the mail filter seal. I felt the can for leaks a few t...

Thanks Spanners- I'll double check the mail filter seal. I felt the can for leaks a few times with the engine running and found nothing, but I'll look again tonight.

I made a lunchtime run over to Performance Products and picked up a new hand pump (old design though [:(!]), throttle pivot mount, and some new hoses. Hopefully one of those will help the engine run smoothly.
 

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83 300TD/97 E320/98 SL500
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Discussion Starter #4
So I checked the main fuel filter and everything is on tight. Unfortunately, the fuel exp...

So I checked the main fuel filter and everything is on tight. Unfortunately, the fuel expansion tank decided to split at the seam and spill diesel all over the spare tire.

The new accelerator pivot mount and hand primer pump are installed and everything looks good, and the expansion tank is on order. Hopefully this fixes everything...I'll see in a couple days.
 

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83 300TD/97 E320/98 SL500
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Discussion Starter #5
Everything Fixed!

I promise, this will be the last reply I make to my own post [:D]

So, just to recap the problems I was experiencing- after the 180K mile service, the car seemed extremely sluggish- off the line, the car would crawl until RPM's reached ~1100. Idle felt uneven, with a sporatic missing sensation. At speed, there was a sensation of lost power throughout the RPM range.

The fix- a suspected leaking hand primer pump. I replaced the pump (with the old design pump), along with the accelerator pivot mount (now the IP gets full deflection when I mash the pedal), and the fuel expansion tank (unrelated incident). THese were coupled with the usual service (valve adjustment, fluids change, etc.)

The result- more power throughout the RPM range than I ever had before. Not amazing, but nevertheless very noticable. Smooth idling, even when hot! The car moves authoritatively from a standstill.

I'd recommend the hand pump replacement for anyone experiencing strange idling/driving behavior- $10.56 for the old design at Performance Products. Worth a try.
 

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1983 300Dturbodiesel
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what is the "hand pump"? is that the thing inbetween the 2 filters on the fuel line that...

what is the "hand pump"? is that the thing inbetween the 2 filters on the fuel line that you unscrew slightly to pump?
 

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83 300TD/97 E320/98 SL500
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Discussion Starter #7
Yes...

between the inline filter and main fuel filter.

The old style is a plastic handle that you unscrew to pull out and pump. If this leaks diesel as you're pumping, it's bad. There's a new style hand pump that has a black spring-loaded handle. I just figured that if I got an old design pump and it lasts another 20 years, I'm good.

Fairly quick to replace- you can use a crows foot wrench or grip lightly with a vise grip.
 
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