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1965 W111 220S, 1968 W108 280S, 1970 W108 280SE, 1990 W126 500 SE, 1992 R129 500SL & 1995 E320 S124
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73 Posts
Discussion Starter #1
Hey there guys,

I have a 1990 500se and ever since I've taken delivery, which is now a couple of months ago, I have felt that the car is not performing the way it should. Don't misunderstand me, I fully understand that this is no street racer! I have tried checking the ignition timing and have come to understand that it is set electronically. I have changed the EZL (sourced from a 560) due to the original failing, but still the performance is not what I expected. I base my conclusion on the fact that I drove other 500's before I bought this one and they went like hell compared to my current car. It seems to be sluggish and has a 'flat spot' when you accelerate hard from standstill. Is there any way that I can check the ignition timing and more importantly adjust it? What do you suggest/recommend I check to improve the situation?

The fuel economy has gone for a ball of s.... of late and I don't know why, as I had it serviced less than a 1000km ago... I must add that I don't trust the mechanic who did the work all that much, although he came recommended.

I would appreciate your inputs.

By the way just to be sure, my car is fitted with the 117.965 motor (I believe?)

Thanks and regards,

H
 

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Registered
1965 W111 220S, 1968 W108 280S, 1970 W108 280SE, 1990 W126 500 SE, 1992 R129 500SL & 1995 E320 S124
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73 Posts
Discussion Starter #2
I find it very hard to believe that there isn't a single member who doesn't have two cents worth of advice to offer...
 

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Registered
1983-2007 MB's
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8,015 Posts
I'll throw in my 2 cents:

Distro rotor and wires in good nick? What plugs did the mechanic use? Should be non-resistor ones as well.

Sounds like you're running overly rich - black smoke? Condition of the plugs when you pull one to inspect?

If the car has cats, check them - plugged cats will give the symptoms you have.

EZL adjusts timing, so you shouldn't try to mess with timing. But you can check it to ensure it is on spec following the timing sticker on the radiator support.

Timing chain/guides OK? No chain slap (which will give timing variance)....

how many KM's on the car? Is your car a tri-y or Euro log manifold car?
 

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Registered
1965 W111 220S, 1968 W108 280S, 1970 W108 280SE, 1990 W126 500 SE, 1992 R129 500SL & 1995 E320 S124
Joined
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73 Posts
Discussion Starter #4
Thanks Bondavi, much appreciated.

The distro rotor and wires are in good nick. The mechanic used the plugs the manual advises, which are non-resistor. Not sure about the make, but most decidedly not Champion if that is where you're heading!

I have not pulled a plug to inspect, but I was told by the mechanic that he set the mixture a tad richer than indicated, as he felt the cars ran too lean at the coast, which could cause valves to burn... It is VERY windy where I live, so it is difficult to see any smoke in the rear view mirror. If I lifted the revs without driving the car, black smoke would be evident, but not much.

The car does not have cats - it's a South African assembled car.

I would dearly appreciate if you could send me a pic or the spec as described in the sticker you talk of. My car does not seem to have this sticker.

The car has 296500 odd kms on the clock and I think that it could do with a new timing chain and guides. Could this have such a major effect on the performance?

I am not sure what manifolds the car has on it "tri-y or Euro log manifold", but they are not solid. If memory serves, they have what looks like expansion bellows in them... Could you possibly give me a brief description of the manifolds you are talking about?

Thanks for your two cents, it's worth millions to me!
 

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1985 500 SEC EURO AMG/LORINSER; 1988 560SEL, 1995 S500 Sonderschutz
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3,679 Posts
Did you lube your throttle linkages?
 

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Registered
1965 W111 220S, 1968 W108 280S, 1970 W108 280SE, 1990 W126 500 SE, 1992 R129 500SL & 1995 E320 S124
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73 Posts
Discussion Starter #6
Yip! They're not sticky if that's the train of thought here...
 

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Too many to list
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8,580 Posts
Is your trans starting in second gear? That is the obvious sluggish acceleration issue on many mb

You may need a first gear start mod

Then again,

300k km is about 180,000 miles- not unusual for an engine to start getting tired
 

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Slightly creased
2015 ML 400 x 2
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16,597 Posts
from doing some recent research, there seems two schools of thought regarding the interchangeability of EZL's. Some say they can be, some say they must be from the same model.

I am just wondering if you perhaps could try an EZL from a late model 500 to see if that is the problem?
 

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1991 300SE W126 Collector owned, maintained 90k mi
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177 Posts
Hi I changed my fuel filter as regular maintenance and I was quite surprised with increased acceleration. Sometimes the least obvious is the solution.
 
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