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W126, R107, W210 AMG, W221
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342 Posts
Discussion Starter #1 (Edited)
My CE has 100.000miles and even though it is in a very good shape, the most important part (engine) seems to deliver only about 150±hp. We tried to address this issue with removing the cat :D which worked well but still, it is not 100% solved. It seems like there somewhere is a problem but we are not able to locate it. The engine is clean, no oil leaks, transmission in the same condition.. so what else can it be? Eg. when you kick-down, you got to wait few seconds and sometimes nothing happens. When you drive in manual mode, the engine revs well but still, when compared head-to-head with my friends 300 CE-24, he is WAY faster (with a bit older car and much worse optical / tech condition).
When I accelerate hard, I hear a thump/clunk sound from the rear.. it is a rear diff.. right?
Please help me solve that..
 

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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12,745 Posts
When was the last time the car was properly tuned with correct plugs (non resistor, pure copper), wires, cap, rotor, coil? When was the last time the air/fuel ratio was checked? All vacuum lines/connections checked?

The "clunk" you mentioned probably occurs when you shift from reverse to drive as well. I suspect your rear differiential mounts are shot and maybe the forward diff mount. What is the condition of your flex disk? I would also inspect rear control arms and strut bushings.

Jayare
 

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W126, R107, W210 AMG, W221
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342 Posts
Discussion Starter #5
When was the last time the car was properly tuned with correct plugs (non resistor, pure copper), wires, cap, rotor, coil? When was the last time the air/fuel ratio was checked? All vacuum lines/connections checked?

The "clunk" you mentioned probably occurs when you shift from reverse to drive as well. I suspect your rear differiential mounts are shot and maybe the forward diff mount. What is the condition of your flex disk? I would also inspect rear control arms and strut bushings.

Jayare
None of the above was checked. Thanks for the directions..

Regarding the rear diff .. what could be the cost of the repair in the worst case scenario? Just to have an idea..
 

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W124 Moderator
86 190E 2.3L 16V, 2 95 320TE's, 02 S500
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12,745 Posts
To hard to guess on repair cost of elements in the rear suspension. I'd suggest a qualified tech take a look and determine the proper diagnosis/solution/cost.

Jayare
 

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Fuck you
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116 Posts
Have you checked the duty cycle? Mine was at 30% (1991 300E-24) and had never been adjusted - the plastic cap on the tower was still in place.

test it and get it in the 47-53% (as close to 50%) range.
 

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Premium Member
SL's & 500E's
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1,978 Posts
Search feature

Have you checked the duty cycle? Mine was at 30% (1991 300E-24) and had never been adjusted - the plastic cap on the tower was still in place.

test it and get it in the 47-53% (as close to 50%) range.
I really try to use the search feature to save repeats of explained problems, but doing a duty cycle search came up with 463 pages of info, I spent time going through the first page, then gave up.

Hate to ask for a rehashed explanation, but you can save me 40 hours out of my life by posting back either a link or a 5 cent explanation.

So far I've read it's an adjustment of some sort pertaining to air/fuel, is that right?

Sorry again for asking something that may have been beat to death, but I've not seen it before and the DIY stickys don't seem to have it.

If anyone knows where there is a DIY for this adjustment, I'd like to see it.

Tanx...
 

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'89 300TE, '79 450SL, '01 ML320
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1,051 Posts
First I'll give my 5 cent explanation of the search feature, we all know it sucks, but it does work :)
Search just the forum for the car you're working on to start. By searching 'duty cycle' in only the w124 forum,
the results are narrowed down to 143 pages.
Next look at the results column marked 'views', pick the one with the most views. There's a reason
people keep coming back to that thread, it either has a pic of a half naked chic or the answer :)

This thread has 17,551 views
http://www.benzworld.org/forums/w124-e-ce-d-td-class/1231077-fuel-mixture-adjustment.html
also contains a link to this page:
BOSCH KE3-JETRONIC MIXTURE ADJUSTMENT

Everything you need to know is in those two links... I think ;)




Fish
 

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89 300E; 00 E320
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2,515 Posts
In Sticky: 124 DIY Thread under Engine/Transmission it is Fuel Mixture Adjustment, which is the 1st link from Fish above.
Maybe a picture to begin that is near the end of the thread at this time.

The duty cycle is used to adjust fuel mixture and is a measurement of how often the mixture actually adjusts / or doesn't adjust depending on how you look at it. The reason it adjusts is because the Oxygen/Lambda sensor sends a signal of how rich or lean the mixture is and the computer adjusts the fuel mixture accordingly.

You can use a multimeter to measure voltage or duty cycle on pin 3 of X11 diagnostic socket. Not all of our 124's have this pin available and you can possibly use reading from O2 sensor to make adjustments like hispassion did here. If you measure voltage there is a calculation that will produce duty cycle.

Some multimeters provide a duty cycle reading in % and are a great way to adjust the fuel mixture. The % on reading of the duty cycle on the craftsman that many use is not the "Mercedes Benz" duty cycle; it is opposite. In other words you can subtract the craftsman duty cycle % from 100 % and have the Mercedes duty cycle. So if my duty cycle is showing 30% then it would be 70% Mercedes duty cycle. That is important when taking some of the static measurements for other diagnostics, but does not really matter for this discussion if you are just interested in making fuel mixture adjustment.

And it really just confused things; because, you adjust the fuel mixture close to 50% and need 10% or less difference in duty cycle between reading at idle and reading at 2500 rpm's. Mercedes does not give an exact % that would the best setting anyway. Most here now use the duty cycle of 45%-48% on the craftsman multimeter as a target because Jayare has found it works best.

So, get your engine hot. Plug multimeter in X11 socket, black 2, red 3 and set the fuel mixture to 45% to 48% duty cycle like in the picture above.
 

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Premium Member
SL's & 500E's
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1,978 Posts
Yup, it's all there, tanx Fish & cbc, exactly what Im looking for.

I think it's a worthy topic for a sticky in the DIY threads
 

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E220 CDI 2003
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62 Posts
I do not know if you have the same engine, but I came across this one on a dutch site (W124Club Forumoverzicht).

In short check the bolt which holds the ground wires, some where on top of the motor.

Part 1:

Part 2:

Arno
 
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