8-9 mpg on 2002 Ram 5.9!!!
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RE: 8-9 mpg on 2002 Ram 5.9!!!
ORIGINAL: HankL
The front O2 sensors should be 'flipping' rapidly from 0.2 volts to 0.8 volts. This flipping is normal and necessary. The back two O2 sensors should be changing voltage more slowly but still flipping above and below 0.45 volts if they are healthy.
The front O2 sensors should be 'flipping' rapidly from 0.2 volts to 0.8 volts. This flipping is normal and necessary. The back two O2 sensors should be changing voltage more slowly but still flipping above and below 0.45 volts if they are healthy.
Champion
Joined: Aug 2005
Posts: 3,313
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RE: 8-9 mpg on 2002 Ram 5.9!!!
That is just a bit "rich"
but the downstream O2 sensors read higher voltage (less oxygen)
and the idle air to fuel mixture
is meant to be richer than 14.7 (0.45 volts)
especially if the coolant is less than 195 degrees
after a cold start.
Even so
it would be consistent with one or more fuel injectors
that are 'dribbling' fuel
when they should be completely shut off.
Deposits at the tips can cause this.
It is still a good idea to do a highway MPG test at a steady 60 mph
to find out if the engine is efficient.
8-9 MPG is quite possible even for a 'healthy' Ram
if you are accelerating hard in city-style driving.
A healthy 2002 Ram 5.9V8 46RE
that gets 19 MPG at a steady 60 mph on the highway
will only get 4 to 6 MPG during heavy acceleration in the 0-45 mph speeds.
but the downstream O2 sensors read higher voltage (less oxygen)
and the idle air to fuel mixture
is meant to be richer than 14.7 (0.45 volts)
especially if the coolant is less than 195 degrees
after a cold start.
Even so
it would be consistent with one or more fuel injectors
that are 'dribbling' fuel
when they should be completely shut off.
Deposits at the tips can cause this.
It is still a good idea to do a highway MPG test at a steady 60 mph
to find out if the engine is efficient.
8-9 MPG is quite possible even for a 'healthy' Ram
if you are accelerating hard in city-style driving.
A healthy 2002 Ram 5.9V8 46RE
that gets 19 MPG at a steady 60 mph on the highway
will only get 4 to 6 MPG during heavy acceleration in the 0-45 mph speeds.
