10 - 12 mpg! Smthin' is wrong...big tym!
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From: Gledale,Ca.
1989 300E
10 - 12 mpg! Smthin' is wrong...big tym!
10 - 12 mpg on the street is not really acceptable. Changed my O2 sensor, cap, rotor. What is going on! My car is an '89 300E with 135700 m. What could be the problem? 
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From: Seattle, WA
1992 300e
How are the air filter, plugs and wires? When was the last time you checked the tire pressure? Has it lost it's pep, maybe check the cat too. Do you ever run and fuel system cleaner in your gas, like Techron? How do you drive it, like a 300 or a e55 wannabe? The go pedal has a Big time effect on mileage.
HTH,
Ron
HTH,
Ron
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Mercedes-Benz w124
how do i know when to replace the cap/rotor/plugs/wires? same thing here, 02 sensor and fuel filter and a new kandN filter was put in recently and i only get 17mpg mixed driving. and i also just put in a fuel cleaner about 100 miles ago. i would like to know also.
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From: Long Beach, Ca
lots of cars
change to the gold injectors too and you will get better mpg also i adjusted mine so i can get 23-25mpg 30% street %70 highway but it's a real pig unless i press the pedal more than half way.
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From: Gledale,Ca.
1989 300E
Originally Posted by YNVDIZW124
change to the gold injectors too and you will get better mpg also i adjusted mine so i can get 23-25mpg 30% street %70 highway but it's a real pig unless i press the pedal more than half way.
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From: Gledale,Ca.
1989 300E
Originally Posted by TheDoughboy
How are the air filter, plugs and wires? When was the last time you checked the tire pressure? Has it lost it's pep, maybe check the cat too. Do you ever run and fuel system cleaner in your gas, like Techron? How do you drive it, like a 300 or a e55 wannabe? The go pedal has a Big time effect on mileage.
HTH,
Ron
HTH,
Ron
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From: Gledale,Ca.
1989 300E
Originally Posted by TheDoughboy
How are the air filter, plugs and wires? When was the last time you checked the tire pressure? Has it lost it's pep, maybe check the cat too. Do you ever run and fuel system cleaner in your gas, like Techron? How do you drive it, like a 300 or a e55 wannabe? The go pedal has a Big time effect on mileage.
HTH,
Ron
HTH,
Ron
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From: Seattle, WA
1992 300e
I swiped this off the net because it was faster than typing 
Sounds like your cat is fine though.
There are two ways a converter can fail:
It can become clogged.
It can become poisoned.
There really is no "inspection port" for the consumer or mechanic to see an actual clog in a converter. Often, the only way to tell if a catalytic converter is malfunctioning (plugged) is to remove it and check the change in engine performance. When a clogged converter is suspected, some mechanics temporarily remove the O2 sensor from the exhaust pipe ahead of the catalytic converter and look for a change in performance.
A catalytic converter relies on receiving the proper mix of exhaust gases at the proper temperature. Any additives or malfunctions that cause the mixture or the temperature of the exhaust gases to change reduce the effectiveness and life of the catalytic converter. Leaded gasoline and the over-use of certain fuel additives can shorten the life of a catalytic converter.
A catalytic converter can also fail because of:
Bad exhaust valves on the engine
Fouled plugs causing unburned fuel to overheat the converter
Sometimes you can tell that a converter is clogged because you don't go any faster when you push the gas pedal. Also, there usually is a noticeable drop in gas mileage associated with a clogged catalytic converter. A partially clogged converter often acts like an engine governor, limiting the actual RPMs to a fast idle. A totally clogged converter causes the engine to quit after a few minutes because of all the increased exhaust back pressure.
Sounds like your cat is fine though.There are two ways a converter can fail:
It can become clogged.
It can become poisoned.
There really is no "inspection port" for the consumer or mechanic to see an actual clog in a converter. Often, the only way to tell if a catalytic converter is malfunctioning (plugged) is to remove it and check the change in engine performance. When a clogged converter is suspected, some mechanics temporarily remove the O2 sensor from the exhaust pipe ahead of the catalytic converter and look for a change in performance.
A catalytic converter relies on receiving the proper mix of exhaust gases at the proper temperature. Any additives or malfunctions that cause the mixture or the temperature of the exhaust gases to change reduce the effectiveness and life of the catalytic converter. Leaded gasoline and the over-use of certain fuel additives can shorten the life of a catalytic converter.
A catalytic converter can also fail because of:
Bad exhaust valves on the engine
Fouled plugs causing unburned fuel to overheat the converter
Sometimes you can tell that a converter is clogged because you don't go any faster when you push the gas pedal. Also, there usually is a noticeable drop in gas mileage associated with a clogged catalytic converter. A partially clogged converter often acts like an engine governor, limiting the actual RPMs to a fast idle. A totally clogged converter causes the engine to quit after a few minutes because of all the increased exhaust back pressure.
Last edited by TheDoughboy; Oct 4, 2005 at 03:25 AM. Reason: typo
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From: ISRAEL
300TE
bad mpg
i took out my cat (300te 1991) because the car was stalling and
i had reasonable suspicion that the cat is bad (225000km).
and after that i replace injectors, rotor,cap,o2,govener.
so now the car has more power, but the mpg is bad, and there is more noise
from the exhaust in the car. i check also the HC at the exhaust and it was
very bad around 800 insted of 300 so it means that my motor is running
like a fuel drunk . so i adjust the CO to a min. (the motor is vibrant a little)
in order to save fuel.
Does the cat. take place in o2 sampling? or is it conjuncture that it happend
after i took the cat. out? the noise problem i understand.
Thanks OFER.
i had reasonable suspicion that the cat is bad (225000km).
and after that i replace injectors, rotor,cap,o2,govener.
so now the car has more power, but the mpg is bad, and there is more noise
from the exhaust in the car. i check also the HC at the exhaust and it was
very bad around 800 insted of 300 so it means that my motor is running
like a fuel drunk . so i adjust the CO to a min. (the motor is vibrant a little)
in order to save fuel.
Does the cat. take place in o2 sampling? or is it conjuncture that it happend
after i took the cat. out? the noise problem i understand.
Thanks OFER.
