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1997 Mercedes-Benz S500
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213 Posts
Discussion Starter #1 (Edited)
Hello everyone,

I'm going nuts over my 90' 560SEL. I have replaced the following parts within the last month:

Vaccume hoses (3 by ICV, air tubes on each injector, cross over pipe)
Fuel Filter
Motor and transmissiion mounts. (engine Shocks are good)
Brand new Idle control valve.
Engine oil 10w40 Royal Purple Synthetic

Previous owner replaced wires (Beru), plugs (Bosch WDCO), distributor and rotor on Jan 8, 2009 at 116,900 miles, according to the receipt from MB Dealer. The car right now has 132,593 miles.

The RPM needle is steady at 670RPM at Idle and 550 in Drive. There might be some insufficient movement, but I can't see it. When the car is warm the oil gauge, with a car in Drive, shows 1.5 to 1.55.
Lambda around 50% (max voltage 13.6 and 7.2-6.4 between pins 2 and 3 at the x11 connector). Why is it still shudders from time to time, and why the motor shakes:surrender:. I put a flashlight on top of the intake box and it dancing. Also the exhaus pipe is shaking.

Any ideas will be apreciated.
 

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1989 Mercedes Benz 560 SEC
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16 Posts
Hey,

Not sure if you changed them but i had a similar issue in my 560 sec and i changed the spark plugs and the car stopped vibrating.. hope it helps!
 

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1997 Mercedes-Benz S500
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213 Posts
Discussion Starter #4
Hey,

Not sure if you changed them but i had a similar issue in my 560 sec and i changed the spark plugs and the car stopped vibrating.. hope it helps!
That was done by previous owner in January 2009. 16,000 miles ago.
what is the life span of the WDCO plugs?
 

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1984 500SEL
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91 Posts
same situation here. almost everything new. car drives perfectly, engine idles good and oil pressure good. there is sometimes a noticeable shudder (not much, but obvious that it is present). My engine mounts could use replacing but no way I can tackle that until the summer so if you don't solve your problem 'till then I'll update you.
 

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1997 Mercedes-Benz S500
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213 Posts
Discussion Starter #6
same situation here. almost everything new. car drives perfectly, engine idles good and oil pressure good. there is sometimes a noticeable shudder (not much, but obvious that it is present). My engine mounts could use replacing but no way I can tackle that until the summer so if you don't solve your problem 'till then I'll update you.
i paid 70 dollars for parts and 200 for labor which included, oil change and fuel filter. I spoke to my mechanic and he told me that on 560's timing chain usualy doesn't strech, its the 420 problem. What is a useful life span of Bosch spark plugs? As far as I remember it should be 15,000 miles. (I'm notsure).

The engine shock absorbers are good, according to the mechanic. I sprayed 4 cans of carb cleaner all around and 3 bottles of techtron fuel injector cleaner every tank, running on Sunoco 93 Ultra and same thing.
I don't know what to do.
 

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2,043 Posts
find a new mechanic, one that has a clue...
my buick needs a belt tensioner BAD, it never sequels but it does shudder like hell a lot... could be sparkplugs AND check to see if all your ignition wires are connected only things i can think of...
 

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1997 Mercedes-Benz S500
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213 Posts
Discussion Starter #9
Happy Thanks giving everyone,

Ok, yesterday I have purchased two thermo valves (Black and red) and a four prong intake temp sensor, I read somewhere that it does wonders to shaky idle. I have measured today the resistance across the two prongs and it came different, even though it has to be identical. 275 Ohm on one pair and 220 Ohm on the other. Could that make a big difference?
Question, how often do i have to change plugs? 15,000 miles? How do i know if my coil went "a la shit"?
Also, I disconnected a connector of E.H.A. valve while running a car and there was no difference, Should i be worried or i'm doing something wrong?
 

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' 91 350sel, '12 s350, '18 144 sprinter, '08 sl550
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328 Posts
have the same idle issues...........did the vacuum line thing, the 2 thermo vacuum switchs, things got much better on cold start, but still "shakes" at times...plugs and wires seem recently updated by previous owner....
i m afraid to bring to mb service, they ll want to do fuel distributer or something expensive like that..
 

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1997 Mercedes-Benz S500
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213 Posts
Discussion Starter #11 (Edited)
have the same idle issues...........did the vacuum line thing, the 2 thermo vacuum switchs, things got much better on cold start, but still "shakes" at times...plugs and wires seem recently updated by previous owner....
i m afraid to bring to mb service, they ll want to do fuel distributer or something expensive like that..

My fuel distributor has been changed/repaired by previous owner.

What is the recommended tire pressure. If i go by the sticker on the inner fuel door, which says 28psi, my car eats rubber on the inner side at the rear wheels. Negative camber. I put 32psi, Ok so far. Is it going to damage the suspension?


Also, what might be the problem if it takes 2-3 seconds of cranking to start the car if it stands for a few hours?
If I try the second time it starts with half a turn. Fuel filter brand new Bosch.

Happy Turkey day everyone
 

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' 91 350sel, '12 s350, '18 144 sprinter, '08 sl550
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328 Posts
MINE , LOOKING AT THE REAR WHEELS THEY SEEM LIKE THE TOP IS IN, AND ARE ALSO TURNED IN KINDA PIGEON TOE LOOK..

DOESNT APPEAR TO BE ANY ADJUSTMENT FOR REAR..
 

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1991 420 SEL
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6 Posts
The rough idle strikes me as a secondary ignition system problem.
Refering to the long cranking, my gut says the fuel pump may be getting weak. Do you have trouble getting on the highway? Low power during HEAVY acceleration? Could also be poor or weak connection in the electrical system.
 

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1997 Mercedes-Benz S500
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213 Posts
Discussion Starter #15
The rough idle strikes me as a secondary ignition system problem.
Refering to the long cranking, my gut says the fuel pump may be getting weak. Do you have trouble getting on the highway? Low power during HEAVY acceleration? Could also be poor or weak connection in the electrical system.
Well, I never had a benz before I don't know how it should perform, but i did have a crown vic. and I think they perform the same. Today I was driving 90mph and it's pooling pretty good.

The only thing is that my fuel economy is 13mpg mostly hwy. However, I like to warm my car to 60 or 80 before i start moving.

What is the average life span of a fuel pump and where should i start looking for the loose connection. I know that Coil is original as well as the fuel pumps 133,786 miles.
 

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1991 420 SEL
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6 Posts
Well, I never had a benz before I don't know how it should perform, but i did have a crown vic. and I think they perform the same. Today I was driving 90mph and it's pooling pretty good.

The only thing is that my fuel economy is 13mpg mostly hwy. However, I like to warm my car to 60 or 80 before i start moving.

What is the average life span of a fuel pump and where should i start looking for the loose connection. I know that Coil is original as well as the fuel pumps 133,786 miles.
With the strong acceleration on the highway I would guess the fuel pump is ok. There is really no "expected lifespan" of fuel pumps.
Maybe replace the ignition coil. Won't hurt to try but best to test the strength of the ignition coil.
 

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1997 Mercedes-Benz S500
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213 Posts
Discussion Starter #17 (Edited)
Well, today i decided to pull my plugs out and measured the gap, it was 0.038-0.04. I have read somwhere that the gap supposed to be 0.032. So, i gapped 3 out of 8 plugs to 0.032 and it feels much better, tomorrow I'll gap another 5 and see where it takes me.

How do you test ignition coil??
 

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1997 Mercedes-Benz S500
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213 Posts
Discussion Starter #18
have the same idle issues...........did the vacuum line thing, the 2 thermo vacuum switchs, things got much better on cold start, but still "shakes" at times...plugs and wires seem recently updated by previous owner....
i m afraid to bring to mb service, they ll want to do fuel distributer or something expensive like that..
I've just changed all the temp sensors, was showered by coolant all over:). Cold start problem resolved. However, when I started the car cold and sprayed carb cleaner on 3rd and 4th injectors idle picked up. I guess my injector seals are bad. How hard is it to change them?
Also, While I'm at it should I change the injector as well? The car has 133,730 miles. I heard the life span of the injector is 100,000 miles.
I found a new bosch brass one is 37 dollars, but the alloy/grey one is 75, what is the difference?
 

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1997 Mercedes-Benz S500
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213 Posts
Discussion Starter #19
Just found a video on youtube. my engine shudders just like that, but without the idle going up and down. Idle is steady.

Is it realy a camshaft problem or it might be an injector issue??
 
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