qades

Hi every body, I drive C-200 1998. Few weeks ago my car engine starts to hesitate. When in idle its like one of the cylinders in not firing correctly, but its not that bad, the problem is when I reach the speed of 80km/h it does'nt want to go any more until I take my foot of the accelerator, then I proceed until I reach 120km/h and then it wont go any more, no matter how far I push the accelerator. So, I changed the spark plugs, and there were a little improvement in idle only, then I changed the spark plug wires and no improvement. I opened the MAS and carefully cleaned it (it was clean), I checked the exhaust system and cleaned the air filter.
Could some one please detail me in such an experiance. Thanks.

PhilipM1

you might have a bad valve. do a compression check. and them your OEM spec for each cyl. it should be + - 5pounds. if it isnt do a vlave job or replace the head. If it come back ok let me know ill give you some mroe options.

Whatstheprtnmbr

You may have a bad injector or multiple. Have you changed the fuel filter?
It sounds like there is a choking problem going on with your fuel system.
There is a sock inside the fuel tank inlet that may need to be changed also.
The symtoms you described sound mostly like a injector isssue.
Hope this helps

PhilipM1

do you have hesitation and crapy driving all the time and shaking? Or is it just at stop and slight go. if it was a fuel problem I think it would be connsitent with the RPM and no so much with MPH.

How many miles do you have on your car?

I might do a comrpession test just in case. there not to expensive i dont think. If you have the tool and a friend you can do it yourself.

Im not an expert and i would normally say fuel delivery too, but its the topping out thing that makes me think otherwise. I dont know if anyone else has any toher opnions?

good luck.

qades

Thanks for your quick reply, the hesitation is not all the time, its at first increasing, at 80km, and at 120km but at all three speeds when I let the accelerator and then increase it goes, but it does'nt go more then 120km.
It can be felt at idle but not that bad.
I did a computer diagnosis and got (P0170 right cylinder mixture adaptation reaches limit value) & (B01010 voltage supply tpp low). Does this gives an indication of something.

Whatstheprtnmbr

Take a look at this thread if you like, I also had that code about a year ago.
If this is actually the code you had then its time for a air mass meter, the sensor is bad and must be replaced. There really is no chance in cleaning them. http://www.benzworld.org/forums/w210...alve-stop.html

dafowler88

Dude, you'll probably have to change the ignition coils. Not too expensive if you do it yourself. About $80 eace I think. There are 3 coils on my C280 but I'm not sure about a C200.

qades

Thank you v.much, now I have two options the air mass meter and the ignition coils, the thing is how would I know which one is more suspected.
Are there any tests to make sure, instead of wasting my money in replacing undefective parts.

dafowler88

Well, is your check engine light on?

qades

No, check engine light is not on!! and no any indication in the panel!!

dafowler88

Then it's more than likely the ignition coils. MAF, more times than not, if it is malfuntioning will indicate as check engine.

qades

Well, here is my update.
I changed the fuel filter, air filter and both ignition coils, and then I started the car (after having a shower), the car runs v.smooth and I was v.happy. I took it for a ride its really a change, but, the real problem still the same, engine still hesitates in the above mentioned speeds. I think I'll go for changing the fuel pressure regulator, change the sock inside the fuel tank inlet!!! ,do a compression test, and if it not solved then I'll change the car

The thing is, there are many causes for the same symptom. We learn.
Any more options.

PhilipM1

Im going with the compression thing. Let me know how that comes out. I really hope its not that. I dont think its cheap to do a valve job.

Also try, (This is free testing!!)
Drive it normal, when it starts to hesitate, Try putting it in 2nd gear manually. Stomp on it. Let the RPMs run free. Enjoy the engine noise. See if it still comes back with the same promblems in 2nd gear.

(Might be third gear for your car, i know my car hits 60mph in 2nd).

But, put it in the lowest possible gear. Let me know what happens. Dont forget to shift it into 3rd and 4th if it lets you keep going faster.

speedybenz

Try to check for any vacuum leaks. Even the smallest leak will cause the engine to run rough and hesitate.

Jeff

OzC36

I remember a guy once wrote he had a bunch of similar problems that were eventually traced to the fuel filter being installed backwards. Just make sure the arrows point towards the flow direction to the engine.

qades

My update. I changed the fuel pressure regulator, just to take that out of the way, no change what so ever. I did the driving test PhilipM3 mentioned, the car hiesitates in different gears but same speed that is 80km/h and 120km/h. I checked for vacuum leaks, can't find any. I checked the fuel filter direction, its the right direction. The car runs fines, its only in these speeds and it won't go any further. I think I'll go for a compression test, but if any thing wrong with the compression, won't there be a symptom of smoke from the exhaust?!!.

Whatstheprtnmbr

Wondering if you are making progress with the hesitation issue?
Can you run your climate control and check for vacuum leaks under the dash? Listen for a trolley noise or a puffing noise, this would indicate a vac leak within the system. I had to replace a bellow or two and it does make a difference.
The fuel pump relay may deserve a look into also, it serves several functions with the electrical input to the ecu. (2)The temp sensor may be throwing strange values at you described speeds.
The throttle body needs to be looked at also, when is the last time you checked the condition of that?
As mentioned by another member the ignition circuit should be checked out, ie coil, plugs, relays.
If you have a W and S mode try driving in one at a time and see how the engine rpm and hesitation reacts, there is a modulater valve that may be acting up also. How many miles are on this vehicle?

qades

I checked the throttle body, seems ok I even cleaned it.
Do you recommend changing the fuel pump relay.
I did'nt thought of the W and S mode, the is a test I'll do and let you know.
Is'nt it that the climate control for the AC, what is it to do with the engine.?!
My car milage is (184859 km) till now.

Whatstheprtnmbr

The entire vacuum system of the car must be checked for optimum performance. If there is a leak anywhere it spreads like a virus to other areas of the vehicle, it will suck power from your engine.
A bit concerned about if the injectors have ever been serviced? If one is clogged it will send a signal to the ecu and temporarily cut off fuel to the other injectors until they (catch) up. With the milage on your vehicle it would not suprise me if they needed service or changed.
As far as the pump relay goes they are pretty cheap to change and there is a way to test them to see if they are functioning correctly without buying another one. This device does comunicate with the ecu also and if it does not open are close correctly it could cause a temporary delay. You may want to check the relay for corrosion on the leads too.
Do you have to let off the gas to let the engine catch up as if you were feathering the gas pedal when it causes this interuption? Does the engine actually speed up when you are letting up on the pedal? If so this would lead me to believe there is a big restriction or poor flow out of one or more of the injectors. What condition are the fuel lines in? Are they soft or brittle>?
Does this issue happen hot or cold engine temps or all the time?

qades

....Do you have to let off the gas to let the engine catch up as if you were feathering the gas pedal when it causes this interuption?
-Yes-

....Does the engine actually speed up when you are letting up on the pedal?
-Yes-

It happends when the engine is cold and hot.

qades

At last I found the devil, it was the Air Mass Meter Sensor. I just went on and changed it, and waaww, the car is completely diffrent, very calm idle, gear change like silk and car accelerate like a jet. Thanks to every one for their participation in my problem, the only sound I hear at idle is the air compressor making a GGRRRRR noise, if there is any solution for it.
I purchased a Petter Russek Pocket Mechanic Vehicle Manual for my car just to be ready for any future problem, but not exactly what I wanted, can some one please detail me where I can buy a CD or DVD with illustrated drawings of all the parts with their part number. Thank you very much.