C-class Stalling & Erratic Idle

[Martin Bell]

My 1993 C220 Sport Auto (Petrol) has started stalling when you stop at road junctions, etc. The car seems to run fine for first few minutes from cold (& on the open road even when hot, although it "pinks" under load & going uphill). The idle also becomes erratic fluctuating between 500-1500 rpm in a cycle when in park, it eventually stalls if held on the brake in drive.
Since the problem started new spark plugs have beem fitted & system checked for obvious air leaks. I think the throttle body has been cleaned but need to confirm this with the independant garage who now suggest taking it to an MB Dealer.
I took it to a friend of a friend who works for a MB dealer & he plugged it into MB diagnostic machine. This seemed inconclusive, he said it would involve lots of time consuming expensive investigation to trace the exact fault. (He also reset & erased ecu memory codes which cured the SRS airbag light which was staying on after a previous job which involved the battery being disconected.)
He suggests cleaning the throttle body/idle speed control actuator which
may help short or long term but says new one is very expensive!
Any ideas on likely fault or where I should take it to be fixed would be much appreciated , the car is undrivable as it is & I need it soon for a trip to SW France in August!
I am based in Epsom, Surrey/SW London.

Martin 1993 C220 Sport

 

[teky]

http://www.benzworld.org/publications/pub.asp?id=235
http://www.benzworld.org/publications/pub.asp?id=236

this might help

 

[Martin Bell]

Thanks, the Autodata sheets really help, what volume do they come in, my local Garage have 5 volumes but they have nothing on C-class data in them only 190E etc?
Also do you have the Autodata Self Diagnosis-section 15 with checking advice for non-Merc Dealers?

How can you test probe ECM multi-plugs without a "break out box" to maintain connections, most other cars seem to check the plug connections at the tested component end leaving ECM end connected and engine running if required. Does not seem a good idea to poke around in the back of ECM connectors! Can breakout box be bought for reasonable price?
Thanks again for your help.

 

[teky]

break out box is expensive, easiest way to test is probe the wires, you can get sharp probes for your multi meter for that task, my data books for injection go to volume 6 up to year 2000 thats when i pulled out of the buisness "retired" the data books cover just about every car on the market apart from some top names like rr and top sports cars, spos im lucky really because i have worked on just about every car make on the road so i know the systems well, if you do a search on benzworld you will find the data for the c=class on my publications

 

[Martin Bell]

Garage have fitted new Mass air flow sensor part at £300! + labour,+ vat, etc. They say car is slightly better & fault code has cleared but Idle is still not normal & needs more investigation. Anybody any ideas or experience of similar please, or do C-class often become money pits after 10 years & 120,000K?

 

[benzover]

when u open the bonnet just behind n/s headlight theres a valve with MOT written on it disconnect the pipe that goes to the inlet manifold and blank it off if the valve sticks it allows more air into the manifold good luck

 

[Martin Bell]

'93 C220 Mass Airflow Sensor was about £300 with VAT from MB & did not completely solve the idle problem. So a second-hand throttle body unit was borrowed & fitted as a test - at last fixing the idle problem. They are £423 with VAT new from MB!..... so Southern Carbs & Injection in Wimbledon got me a remanufactured one for £175+ vat from BBA-Reman (BBA-reman.com). BBA are a very useful to know company in Kent as they do ABS units, ecu's, throttle bodies, mass meters & catalytic converters, rebuilding your own or exchange if they have core units in stock with 2 year guarantee.
Second-hand price from breakers seems to be approx. £125 but with very limited guarantees so I opted for BBA as I intend to keep the car.
The car now runs better than ever but total cost with labour was £700.

 

[mathewtaylor]

C220 CDI -Keeps stalling when accelerating - please help !

Hi,
My dad really needs your help. Please make an old man happy !
He has a Mercedes C220 CDI, 1999.
If he puts the accelerator pedal down hard, the car will stall and the ECU light comes on.
He has to restart the ignition to restart the car.
He has had the car checked and tuned and they cannot find a fault, although they can see that the car has been stalling.
If you have any ideas then please let me know !
Thanks
Mathew