I have been away for a couple of months and the car was with the wife, upon my return I am noticing that as I speed up between 40 - 60 km/hr and then between 80 - 100 km/hr the car makes weird noises as if it is choking or getting no gas at all, it shakes a bit as if all of sudden brakes are clipping the wheels on and off....if i press on the accelerator more or let go of it completely it becomes normal but lets say if i wanna really speed up from 60 to 100 , I press on the gas and the car speeds up but it seems like as if there is air in the gas line and car chokes and huge resonance can be heard. A friend of mine riding with me pointed out that it cud be the supercharger. I also have been noticing that when i shift from P to R or D , the car becomes real jumpy, i barely let go of the brake and the car jumps ahead.

Has anyone had this problem or any ideas......?

car has 128K km on it, tranny service and supercharger service never done on it, Recently changed sparks plugs coil packs have never bee replaced.

Thanks.

 

Any codes??? Could it maybe be the MAF or O2 sensors? Good luck!!!

 

Download codes - O2 sensors suspect as is TPS. Could be MAF. Do a throttle reset.

Need those codes to stop guessing - Buy an OBDII scanner for $50

 

sounds like a issue with the TPS.

 

I'm sorry, but I have no idea on the problem.

I just wanted to say that everytime I see that truck running with the cape, I can't stop laughing!!

 

thanks guys, i will go check the codes today and keep u guys posted..

 

I vote MAF sensor if at steady speed kinda hesitates (pulsates) quite often.

 

ok guys ..after a few days of trying different things and driving around town at different speeds and burning a tank full of gas to understand the problem...i noticed a few things. your valuable response is required.
First of all...no codes, i checked with the ODB2 reader. I did reset the throttle and it did make a difference but the problem is still there. cud this mean the problem is with the transmission...?..i noticed when i speed up real slowly then it happens very slighlty but its when i hit the pedal a little harder it starts to choke and i really liked what Fanito said....it fu**ing pulsates...at that point i either press the pedal further to take it out of the choking/pulsating or release the pedal thats the best way to describe it and u cud hear a resonance in the back of the car ....its truly strange..I am also noticing a bit of a jumpy shifting from one gear to another.. .......any inputs pross...

 

Oil in the engine or tranny harness?

 

this is a new one....well i dont know if there is oil in the engine or trany harness but i did get some work done on it by MB dealership when the leaking cam sensor recall was on....i didnot really have a problem at the time ...i just simply dropped a few drops on the sensor myself and took it to the stealership to give em a taste of their own medicine.....they did the whole thing for me.....i cud check again though.

 

Coolant leak into tranny?

 

I dunno how to check for coolant into the tranny, i did look into the coolant and it seems to be at the same level as the last 2 years so i figured there is no leak.......any other ideas...this is a strange behaviour once again i am gonna make an attempt to describe it ..have you ever went over pebbles and the car shakes thats exactly what it feels like when i accelarte that the vehicle is going over rocks and pebbles at certain speeds.

 

Sounds like you're due for some basic maint.
Hard to eliminate things that have never been done.

Like, replacing fuel filter 1st, then flushing the tranny.
For me I have not had a coil pack last more than 70-80K absolute tops,
but they wil throw codes for misfire, and shut off the fuel to the cylinder.
But not at 1st. The computer counts the misfires. It has to be like 30 out of 600 cycles for it to shut off the fuel to that cylinder.
So when they 1st start to fail, you get misfires, and no codes. Eventually rather quickly they fail completely. For me I found they fail very close to each other in terms of lifespan.

Read here to see if you have the dreaded Valeo radiator, or ie, coolant in the tranny.
https://mbworld.org/forums/2254029-post59.html
Good point though about the coolant level...it takes a noticeable amount as you will read above.

Otherwise, you might just be one of the many who has a 2003 M271 engine with a faulty head design.
There was a thread on benzworld, a guy replaced the valves in the head and DIY'd.
Cost him 2 grand...
Also check the belt on the SC. Maybe it's slipping?

My old SC had that feeling of inconsistent acceleration...
might have just been the belt. I replaced it with a new one when
it came up on ebay for a good price. You can sell your old one as a core.
I paid 600 then sold the old one for 250 to member who wanted to port it.

For you, I would
a. replace the fuel filter if it's not been done,
b. replace the belt, if not done recently. Check the condition, might be slipping
c. Check the tranny fluid, get a sample, (you can suck it out the fill tube)
send it out for analysis.
d. Climb under the car, check the electric connection at the tranny, pull it off..
is it full of oil? There's a o ring that goes bad.
http://www.installuniversity.com/mb/...ans_oring.html
If it is full of oil, you not only need to replace the oring, you need to clean the harness,
and check the TCU to make sure it's not full of oil which I think is under the floor board on the passenger side..but 1st things 1st.

Also there's the $12 hose issue for your car, check the thread on that...
people in the US are getting that for free.
https://mbworld.org/forums/c-class-w...rk-recall.html
Since you're in Canada, you may want to DIY the hose...
https://mbworld.org/forums/c-class-w...ght=%2412+hose

and the head issue of carbon buildup, ummm...I think a mechanic can use a boroscope to look and see,
after removing the spark plugs...more knowledgeable M271 people here than me.

Lastly it could also be the MAF????
But start with the stuff that costs the least or nothing to eliminate eh?

This should give you some food for thought.

Just noticed one other thing..
"you recently replaced spark plugs".

Check your work.
I did this once, where I didn't torque the plugs enough (they started to vibrate out, and oil in the
hole) AND the coil packs vibrated loose and weren't making good contact with the plugs. Ha, I was trying to not OVER torque, and used a crappy bar style torque wrench that read in inch lbs.
I've since invested in a better one.
Make sure you got the right plugs.

I would check THIS 1st!!!
No matter what, invest in
new fuel filter
belt
coil packs
to avoid being stuck somewhere.
And sometime in the near future flush the tranny.
You're at 75K miles...should still be ok...but it's about time to do it.

Hopefully it's not the head....this seems to be about the time people with M271 have problems with the carbon buildup issue. Valves can't close due to carbon!!

 

Thanks alot dude, even my SR does not give me this much insight and knowledge as much you have given me. And I pay him..haha Thanks once again, I am gonne start workin on it this long weekend. Will keep you posted.

 

Ok ....finally after goin through some of things that were mentioned above, car threw some codes so here they are for your opinion and analysis;

p0365
p0366
p0420
p0600
p0128

I have been gettin p0128 on cold mornings for a while but it would just go away with time. It has to do with the coolant being below the optimal temp,.....but the others are new. 365 and 366 are cam shaft sensor codes so now i am thinking my symptoms cud be due to the off timing because of cam sensor fu*k up which is causing the car to hesitate/vibrate when asked for accelertion which proly in turn is eating up the catalytic converters (p0420)......this is my theory......any thoughts as to what should i do and how should i go about this.....

Thanks a bunch in advance.

 

any ideas guys???

 

P0128 = Coolant Thermostat (Coolant Temperature Below
Thermostat Regulating Temperature)
P0365 = Camshaft Position Sensor "B" Circuit (Bank 1)
P0366 = Camshaft Position Sensor "B" Circuit Range/Performance
(Bank 1)
P0420 = Catalyst System Efficiency Below Threshold (Bank 1)
P0600 = Serial Communication Link Malfunction

Right - You have a number of things wrong here:

Ignore the P0600 - you always get CAN messages when the CPS (camshaft) sensors pack up.

Firstly - replace the thermostat. Should open at 87 deg C - If not the car runs cold all the time. The temp sensors tells the car it's cold which enriches the mixture & screws up the fuel trim.

Replace the Camshaft position sensor - will find you a diagram

Do these two first & then run the car & see if you still get a P0420 - If you do you are in for a new CAT & likely 02 sensors. I'm hoping the rich running is giving you a wrong O2 reading on the post Cat sensor - hold thumbs - You are in the mileage area that Cats are getting tired & O2 sensors are out of calibration & cycling too slowly.

It amazes me that you are not getting misfires, but plug wires will probably be next followed by coils.

Good luck

 

Just to clarify - Do you have the M111 or M271 engine? You are at changeover time

 

Thanks buddy for your insight...its a m271 engine.

 

fuel filter is probably clogged. run 1-2 full cans of seafoam in gas tank and drive the car for a few days, see if that helps the problem. Lots of times that will clear it up. If not it may be beyond a simple fix and you will have to replace it.

 

I beg to differ. Sea foam is not going to fix a shot thermostat & CPS. If you have a clogged fuel filter the corrective action is to replace it.

Sea foam can do no harm but Techron is a vastly superior product for cleaning fuel systems & Benz approved & recommended.

I have to question whether AMS even read this thread before commenting.

 

Here is diagram: 50 is the inlet cam sensor & 70 is the exhaust cam sensor. The diagnostics are telling us that the exhaust cam sensor 70 is at fault. Experience tells me that the inlet sensors usually fail first. We had better listen to the diagnostics unless you want to replace both.



Out of interest - 8 is the crankshaft position sensor & 100 is the knock sensor.

 

I have a quick fix for ya mate, trade it off before it costs you more than it's worth !

 

Nah! - these are normal service items

 

I was not speaking to you, don't assume everyone is talking to you at all times Glyn.