Quote:
Originally Posted by tvpierce
I don't know about Euro cars, but I don't understand how the fuel injection system can function properly without an O2 sensor. 
The system needs to have some means of measuring fuel/air mixture. If there's no O2 sensor, how does it do it? |
The mechanical part of the system is quite accurate, enough so a (warmed up) engine will run quite good without the o2 sensor (open loop mode), without any intervention of the electronic part, although mixture will be on the rich side. The electronics of the CIS-E injection system mainly contribute to refine and optimize the correct mixture ratio taking into account several variables (o2, temp, RPM, timing, vacuum, altitude, etc) when its running in closed-loop mode. It will also ease a cold start/run until the engine has had a chance to warm up to operating temp.
My car did not have a o2 sensor for about 3 years, and it ran just fine. Only thing I noticed was the black sooth that tended to accumulate on the tailpipes and also to some degree on the spark plugs. Nothing that an occasional "Italian Tuning" won't clear up. But there was never a performance issue. I can certainly tell you that.
The lack of performance of DrModiford's 300E sounds to me that the ignition timing might be way too retarded. I would check it with a timing light to make sure its correct. There is also a resistor on the end of a plug (usually found on the left hand side engine compartment) that presets the timing to a certain degree, and if you just pull it out it will advance timing and make your car feel snappier. But the car should run pretty good without doing this in the first place, so I guess your problem is somewhere else.
You can always refit the o2 sensor, it easy. Here's a tread I started when I refitted mine. But keep in mind that if the gasoline (petrol) has added lead, the sensor won't last long and become clogged.
http://forums.mbworld.org/forums/showthread.php?t=200680&highlight=sensor+300e+o2