Irratic running/jerking/hunting C220 W202

[Prickleypear]

HI Guys its me and the merc again

Planned a long trip today but had to turn back home, about 5 km from home at about 120km/h the car dipped like when you take your foot off the accelerator only i didn't, so i stepped on the pedal and everything was back to normal... until about another 5km further when i reached a stop sign, when i stopped the idling was very low almost like the engine was about to cut out and when i pulled away the car was jerking like a learner driver who havent pushed the pedals before.

When i hit 60 km/h everything was smooth again for about another 1km and the car started jerking like its out of petrol it kept doing it all through the speed range so i turned back towards home.

After stopping to turn around it felt very low on power while jerking all the time, i managed to get up to 160km/h on the down hill every thing felt smooth again but still low on power (at 160km), pulling away from the stop sign again i could hardly get 60km out of it feeling as if it was going to die at any moment.

After standing on the drive for a while it started back up normally runs for about 2minutes then the idiling goes down like it wants to cut out and it does if you leave it.

I have replaced the fuel filter, air filter, oil and oilfilter on the service about 400km ago so i dont believe its the fuel filter, i also checked the fuel pipes which deliver a steady stream to the front of the car.

I have read that the MAF sensor and CPS could cause these symptoms, in this case the MAF isnt oily at all so could it still be it?
I still have to check the CPS but am waiting for the engine to cool down first

Is there any way to physically test either these sensors, as in my part of the world it is hard to find a code reader and extremely expensive to get it done at the agency?

Any help and advice will be much appreciated, feel free to ask any questions

Its a 1995 C220 W202 Automatic
Thanks in advance and apologies for the long read

 

[Prickleypear]

Update on what i figured out so far
the above mentioned problem only starts once the engine temp reached 80 degrees and only gets worse the further you try to go.

I got as far to unplug the throttle actuator(black box on the side of the throttle body) and the problem seem to disappear, plug the throttle actuator in again and the problem is back.... so does this mean the actuator is faulty or could it be something else connected to it?

Any help appreciated

 

[carat 3.6]

Update on what i figured out so far
the above mentioned problem only starts once the engine temp reached 80 degrees and only gets worse the further you try to go.

I got as far to unplug the throttle actuator(black box on the side of the throttle body) and the problem seem to disappear, plug the throttle actuator in again and the problem is back.... so does this mean the actuator is faulty or could it be something else connected to it?

Any help appreciated

You might have trouble with the wiring loom, the insulation can degrade pretty badly on that engine. Have a look at the various plugs around the loom, can you see any bare wires anywhere?

 

[hfmscan]

This car must be diagnosed using a computer.
Diagnostic Mercedes, HFM-SFI, read fault code, program, W124, W202

You might have trouble with the wiring loom, the insulation can degrade pretty badly on that engine. Have a look at the various plugs around the loom, can you see any bare wires anywhere?

+1


Mike

 

[Prickleypear]

Thanks Carat 3.6 and hfmscan

Yes wiring could quite possibly be a problem, i have rewired the whole front part of the loom (injectors, temp sensor, knock sensor, coils etc.) but not the actuator, i geuss i will have to open the loom and check those as well, if that is the problem i will probably have to rewire that part of the loom too, including the gearbox connector.

Just out of curiosity, will it make a difference if i move the actuator connector to a reachable position, currently it is on a bracket underneath the inlet manifolf and quite hard to get to?