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Hello everybody,
my name is Gian Paolo, I'm italian. I own a 200E W124 bought in 1990 and I need some suggestion, since I have already changed four mechanics and none is able/willing to find a solution to the problem I have.
The car works fine, of course requiring a good amount of maintenance due to the age of the parts, but in principle it has only one big problem.
If I leave the car parked for many days, one, two, three weeks or even one month, it starts immediately without any problem. Just touching the ignition key and it starts perfectly even before than the startup motor gives a complete turn.
On the other hand, if the car has been parked in the sun for a few days, or if it has been stopped for more than a few minutes and less than one day, it has a lot of problem to start. Last week I have got the car from the airport parking, were it stayed for 6 days under the sun, and it took about 30 seconds to make it start. It started at very low RPM, with evident difficulties to remain on for the first seconds. In this cases, it usually emits some smoke.
So, I have been checking for similar problem on internet, but it seems to me that my problem does not fit completely in the "warm start" or "hot start" issue that is quite common.
First of all, it happens also when the motor is not hot (in the case I have described, for example, the car was cold, not for the passenger standard, but for sure for the motor temperatures ). It seems related to the temperature in some way, but not like in the usual hot start issue.
Secondly, I have tried some of the suggestions given in those cases (like giving some gas) but they have no effects.
These are the things I have noticed:
- there are two moments of the startup of the engine: for a few seconds, the RPM are higher, then they go down to the usual idle RPM.
- when the car starts with difficulties, the econometer is very high, even at 2/3 of the scale in the first phase where the RPM should be higher, then it goes down to 1/3, 1/2;
- if I press the gas during this phase, the motor accelerates, it begins to run smoothly and the econometer goes down to zero, where it should stay when the motor is in idle. Once I release the gas, the RPM lowers until the idle level, then the econometer indicator begins to rise again.
After a few minutes of driving, the idle RPM and consumption are fine, as they should be. Also, once the car is on for a few moments, it does not have any problem in staying on.
So, I have the sensation that the motor is flooding for some reason when the starter is activated, and once the first phase of the startup is passed, the mixture of gas and air is correct.
The car is well maintained, the gas pump is working fine, filters are changed every 10.000km together with the periodic maintenance, so I think that the problem is not there.
I have been reading about the oxygen sensor or the injector controller, but never with the same problems I am experiencing.
Do you have any suggestion of things that I can check or test that I can do?
In this case I have to remove the entire air filter assembly, do I?
When you say "remove the plug", do you mean to unplug the valve or to disconnect one of the two pipes? Does it matter which end?
Just disconnect the valve and try to start the car... ok I need some time to try it out, I don't have a place to do such work easily... I will let you know!
Ok Plutoe, this seems easier to access, I agree to start from here.
No problem for resistors and multimeter, but I don't have any reference to the plugs, pins or parts. Do you have the rest of the manual?
In the meanwhile, I was checking a troubleshooting manual I have here for the W124 and to check the cold start systems it says, in a few words:
- unplug the coolant temperature sensor and check its resistance, then compare it with the table;
- unplug the butterfly (? I guess this is the translation, I don't know the exact technical terms) connector and check the resistance value and compare with the provided table;
- unplug the idle controller plug and connect the controller to 12V, check if there is a clear sound;
- unplug the flowmeter connector and check resistance while moving the plate of the air intake.
I have all the schematics and instructions for these operations. Do you think it is worth to follow them?
There is also a table with the current drawn by the electrohidraulic actuator (?) in the different working conditions of the engine, but I cannot find any indication of where I have to check this current.
"I have all the schematics and instructions for these operations. Do you think it is worth to follow them?"----yes
I do not have any hard copy and use EWA NET WIS which gives me access to all of Ms Daimlers docs---FYI with the older cars it is not as organized as newer cars you have to search for the wiring diagrams and I do not have the time to do all that,however you can help yourself at this site----- http://www.bbbind.com/free_tsb.html
Ok, thank you very much for the link, I will check it and I will let you know the result of the tests! If, in the meanwhile, anyone else has some further suggestion, they are welcome!
Hello, I'm back!
I finally had time to give a look at the car.
The first thing I found is that my car is not as what I have seen on many websites looking for information about W124.
I wanted to check the oxygen sensor to start, and I went right to look under the passenger seat for the plug... and it wasn't there. I found the sensor placed right outside the motor, with the plug inside the battery compartment.
Anyway, I plugged the multimeter and before starting the car, it marked 0.497V. This was compliant with what I have been reading, so it seems that the sensor is working.
With the engine running in idle, the voltage reached 0.7V, then the motor accelerated a bit the the value went down a little, oscillating below 0.7V.
When I stopped the car, the voltage went down almost to 0V, then it began to rise again until the same value seen before of 0.5V.
Another thing that I was able to test was the intake air temperature sensor. I have no reference (and when I look for the part number -009542681-, it turns out that it is for the W123??), I read 1k7Ohm at room (~28-30C degrees) temperature.
Then I tried to remove the air filter assembly to check what was beneath it, but I wasn't able to do it. The pipe marked by the arrow:
was impossible to remove and since it was rigid and plugged directly on the motor cover, I didn't want to break it.
I checked if I was able to see anything useful, but no sign of the other parts you described to check.
So, it seems that the oxygen sensor and the temperature sensor are working.
Now I have a few questions...
How would you proceed to remove the air filter assembly?
Do you know what this part is? (sorry the number is not easily readable in the reduced image, it is 0195455028)
This should be the test port. Anything useful from here to check my issue?
I can plug oscilloscope or multimeter, no problem with that.
If I have some time, I will try to get talking with a guy who runs a shop of Bosh to see if could be something related to the injection controller. Maybe they could give a look if I tell them what to search... I don't understand why this people don't want to fix my car...
In this case I have to remove the entire air filter assembly, do I?
When you say "remove the plug", do you mean to unplug the valve or to disconnect one of the two pipes? Does it matter which end?
Just disconnect the valve and try to start the car... ok I need some time to try it out, I don't have a place to do such work easily... I will let you know!
From cold remove the air filter ,then remove the electric conection you can see .Then try the car ie start it up .
From cold remove the air filter ,then remove the electric conection you can see .Then try the car ie start it up .
Uhh... ok. Is it safe to start the engine without the air filter?
Anyway, to remove the air filter I have the problem of the plastic pipe which goes form the engine to the filter case which I cannot remove (see the image in the previous post with the red arrow). Any idea for that?
As for the part -------128 = EZL part its for the quality of fuel you use it is now set to S = super 98 ron = unleaded fuel .If you run on 95 ron fuel it should be set to N . It retards the timeing a few deg check what ron fuel you use at the pumps...If its been set on S for some time then dont move it , repeat dont move it.
As for the part -------128 = EZL part its for the quality of fuel you use it is now set to S = super 98 ron = unleaded fuel .If you run on 95 ron fuel it should be set to N . It retards the timeing a few deg check what ron fuel you use at the pumps...If its been set on S for some time then dont move it , repeat dont move it.
No no, I was just curious to see what it was, because I wasn't able to find any information on internet, while all the other parts had some description.
Anyway, here I use (and in the last years I have always used) the super unleaded 95. The Super 98 is quite expensive...
So, if I understand correctly, the engine is set for 98 (it is set on S) and I'm using the 95...
gpa I have had a little luck can you go to GOOGLE search put in there ----
M102 Mercedes Manual Index
Second one down on the result page
You will see [pdf] Mercedes Benz . click on this one.
gpa I have had a little luck can you go to GOOGLE search put in there ----
M102 Mercedes Manual Index
Second one down on the result page
You will see [pdf] Mercedes Benz . click on this one.
wow, that's my car! Finally... now the components seems to be in the right place.
I have already printed it and I will study it later today.
How did you know that I had to search for "M102"? I'm getting lost with the codes here... I though the right search term was W124.
Yes you car is a W124 but the engine is a m102 glad its ok you can google all things also on the google search page you will see immages give that a try as well
Well, now that I have some more information, I saw that reading the error code from the diagnostic port was quite simple and I assemble a switch and a led to do it.
It didn't work exactly as I expected, but here is what I got...
- connected to pin 3 of the test port
- car off, led on (??)
- ignition on, led on (??)
- switch pressed for 2 seconds, led brighter
- switch released, led off
- four blinks then led on fixed
- switch pressed again, led brighter
- switch released, led off and nothing happens
- switch pressed again, led on
- switch released, led off and nothing happens
If I forget about the on-off thing, 4 blinks mean "Potentiometer voltage illogical".
Is it the air flow potentiometer?
Damn, I really have to get that pipe off the air filter case, everything interesting is down there...
In the meanwhile, I took two pictures of the fuel indicator at engine switch-on.
The first is at idle:
you can see that the fuel flow indicator is quite high, but I have seen it even higher when the engine starts very badly, it reaches half of the scale.
When I press the accelerator deeply enough, the fuel flow goes down to zero (at is should be when the car is not moving):
No no, I was just curious to see what it was, because I wasn't able to find any information on internet, while all the other parts had some description.
Anyway, here I use (and in the last years I have always used) the super unleaded 95. The Super 98 is quite expensive...
So, if I understand correctly, the engine is set for 98 (it is set on S) and I'm using the 95...
You can try puting it on to the N for 95 ron .The S is for super unleaded 98 ron... You can run the engine with the air box removed. The econometer is about right looking at the pictures and the same as mine .
My economy gauge in my car rest on the far left untill i rev it up .I goes to the right as you use more fuel ,thats when you put your foot down .Check all the small bore plastic pipes you can find around the engine bay ,as they have these rubber conections on them that split,then suck air and you lose vaccume.
Last edited by optimusprime m1; 07-14-2015 at 09:57 AM.
I did it, I was finally able to remove that damn pipe!
A lot of oil down there, by the way.
Anyway, I was able to plug the multimeter to the air intake sensor and I thing that it is definitively broken. I get erratic readings when I move the plate:
The multimeter reading is in kOhm and as you can see it starts around 10k, then when it begins to move it jumps to 30-40k, then it goes down to 6-7k... same on both pins. From 1 and 3 the reading is strange, it is not the sum of the two resistance as I would expect from a potentiometer.
In the meanwhile I removed the battery to check the altitude sensor (one of the valve of the heating system failed and a lot of water entered in the battery vane, so I thought that maybe the sensor could have been affected) and... there is no altitude sensor in my car?
About the economy gauge, indeed, it should remain on the left.
If the injection controller reads wrong the air, it may be putting to much gas (and this would lead to the difficult start I get)...
I think that the air sensor change could be a good try...
As for the part -------128 = EZL part its for the quality of fuel you use it is now set to S = super 98 ron = unleaded fuel .If you run on 95 ron fuel it should be set to N . It retards the timeing a few deg check what ron fuel you use at the pumps...If its been set on S for some time then dont move it , repeat dont move it.
If you are following this opus---be extremely careful with some of these off the cuff generalities---the above statement does not apply to the OP's 102.963
It only applies to 102.983, 103.980 and the 117.968 and these engines only have one ignition map. The ignition timing point is advanced for leaded and unleaded premium and fitted with a special resistance timing plug!!
06-12-2015, 07:35 AM
). It seems related to the temperature in some way, but not like in the usual hot start issue.
---the above statement does not apply to the OP's 102.963
