1994 c220 erratic accel
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c220
1994 c220 erratic accel
I have a 94 c220. at cold start up low idle. i tried to adjust thru use of accel cable. doesn't help. when you slowly accel it gets an erratic idle. in otherwords push pedal down tach goes up and down and car respons accordingly.
i cant find a vac leak. i cleaned throttle. the check engine light is on but when you scan it says no codes.
any ideas.
thanks
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Joined: Feb 2012
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1994 MB C220
I had a same problem with my C220 recently and conducted some back probing test (supported by a MB test plan, and volt-meter) to most perennial problem parts regarding to idling and acceleration. I checked on the spark plugs cable for resistance or conductivity (good); I cleaned the spark plugs which are carbon sooted (cleaned), assuming the ignition coils working perfectly or the fuel injectors; back probed the throttle valve assembly that includes the ISC actuator motor and the potentiometer (working fine); back probed the MAF sensor and found out the problem there, the hot film strip must have fell off because of age and brittleness. Now I believe why others always say to replace the MAF after 50,000 miles. Mine is 62,000 miles.
So my conclusion according to my experience is the MAF problem, the mother of all troubles if it gets broken or fried and has a symbiosis with all sensors can also be affected. The other problem I have is a stuck Fuel pressure regulator, combined with broken MAF it causes my spark plugs to soot with powdery carbon big time but I think it doesn’t necessarily affect the acceleration. Another method of checking the MAF behavior is when the engine is idling erratically, remove the MAF terminal plug (just after the air filter box), when the idling tamed down and abnormally low, well that’s it. Ah yes I also read of countless of complaints about the “check engine light or the scanner codes” on 1994 models doesn’t reflect some problems, must have been the vague crossover of the OBD2 from the 1st gen OBD on particular 1994 models…
So my conclusion according to my experience is the MAF problem, the mother of all troubles if it gets broken or fried and has a symbiosis with all sensors can also be affected. The other problem I have is a stuck Fuel pressure regulator, combined with broken MAF it causes my spark plugs to soot with powdery carbon big time but I think it doesn’t necessarily affect the acceleration. Another method of checking the MAF behavior is when the engine is idling erratically, remove the MAF terminal plug (just after the air filter box), when the idling tamed down and abnormally low, well that’s it. Ah yes I also read of countless of complaints about the “check engine light or the scanner codes” on 1994 models doesn’t reflect some problems, must have been the vague crossover of the OBD2 from the 1st gen OBD on particular 1994 models…
Last edited by Dino X; Oct 3, 2012 at 02:15 AM.
