C240 Power Help Required

[chinaldino]

Hi

I have a C240 (Dec 2002). It had been running ‘tight’ and did not seem to have much power and had these symptons:
Fuel economy is not great; Struggles to kick down properly; Lack of power; Not free revving when driving..

It went for a service and the following replaced: Oil filter; Air filters; fuel filter; 12 spark plugs; Air Mas Sensor. There were no fault codes.

Now with all changed there is still no difference in power.. L

Any ideas much appreciated?

 

[stevesey]

MAF would be the first thing to check, but you've had it changed - however it still might be worth disconnecting the MAF and seeing how the car runs (better or worse).

 

[c240yaz]

You need to check if they actually did replace what they said they replaced. What is the milage ?

It has been known for them to charge you for the plugs, or other, and not even bother to replace what they claim to have replaced.

It happened to me in the past. Take it back to who serviced it and tell them the car is runing worse than before you gave them it.

When you change the plugs on a V6 240, the difference in accelleration is ussually very noticeable, for the better.

 

[chinaldino]

Thanks Steve, I'll try disconnecting the maf and testing.

yaz it has 39k. I know the garage and they gave me the old parts.

Oh merry xmas to you all.

 

[c240yaz]

Could be something simple like a plug lead(s) not connected correctly or damaged. It can be misleading refitting these as you need to feel the "click" as they snap on to the plug end.

Last time I changed my plugs, found 2 plug lead copper connectors broken from the core wire, seperate cylinders. Engine still seemed to run smoothly, as one plug on each cylinder was still firing, although lack of power while accellerating.

When I discovered the broken leads and replaced, (approx £25 per lead) difference in accelleration was significant....just a thought.

 

[chinaldino]

ok it went to a dealer and they found no fault codes. They changed the MAF and still no difference. They dropped the cats (exhausts) to see if they are blocked and they came out fine. Checking the actual values they think it could be the throttle valve actuator but did not have one in stock to try. I've read that on 230 krompressor engines they become faulty and the wiring harness also needs changing. Anyone every removed a throttle actuator?

 

[stevesey]

Do you mean throttle actuator or the sender unit - had a couple of older cars where the throttle cable has streched and foot to the floor wasn't = full throttle, until I adjusted (but not sure if the 203 has a remote sender under the bonnet like the 202 or if it's on the pedal assembly).

Recal reading on one of the mbworld threads about sprintbooster that the sender normally gives approx 4.5 volts at full throttle.

The common wiring harness issue was on pre-97 202 C Classes, not heard anything about 203s.

 

[chinaldino]

The throttle actuator. It does not have a cable. I think the 202 had an adjustment as well.