Need Gas Mileage Help
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Joined: Feb 2008
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Need Gas Mileage Help
i have a 93 dakota 3.9. i have had it for about 2 years and love. it has 250,578 miles on it, late last year, it started getting horrible gas mileage... i did a fuel filter and tune up but nothing helped. it went from about 24 mpg to 16... its horrible. its a 5 speed too... what can i do to try to get my gas mileage back up? i really dont want to sell it, but i can t afford the gas anymore. thanks
-Sam
-Sam
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Joined: Aug 2005
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RE: Need Gas Mileage Help
With your 1993 OBD-I PCM computer system
the things you should be most suspicious of are:
bad oxygen sensor
fuel injector(s) that is not closing off and leaking badly
or a fuel injector(s) that have quit
and are causing the PCM computer to richen
the remaining injectors
torque converter lockup clutch no longer working
On the oxygen sensor the correct way to check is to use a scanner to see if it is 'flipping' back and forth around 0.45 volts like it should...a good output is not steady.
If it were my vehicle I would just buy a new NTK oxygen sensor and put it in, but not a Bosch one.
Finding the bad fuel injector(s) is a little harder.
Cheapest first thing is to listen to each injector with a $9 'mechanic's stethoscope'
see hear if each is clicking correctly and sound about the same.
Your could pull them and look at the tip orfices and also the 'catch screens' above for debris. (Have new replacement o-rings on hand.)
It might be simpler to go to a salvage yard and buy a set of 6 injectors off a 1993-1995 Magnum 3.9V6 that have low mileage.
At least one year the Chrysler original part number was listed as 4554127 for the 3.9V6 fuel injector but I am not completely sure that was the 1993-1995 version for the OBD-I system. After 1996 and the switch to OBD-II the V6 and V8 injectors are all the 'common calibration' 23.6 lbs/hr
Good luck with your troubleshooting.
the things you should be most suspicious of are:
bad oxygen sensor
fuel injector(s) that is not closing off and leaking badly
or a fuel injector(s) that have quit
and are causing the PCM computer to richen
the remaining injectors
torque converter lockup clutch no longer working
On the oxygen sensor the correct way to check is to use a scanner to see if it is 'flipping' back and forth around 0.45 volts like it should...a good output is not steady.
If it were my vehicle I would just buy a new NTK oxygen sensor and put it in, but not a Bosch one.
Finding the bad fuel injector(s) is a little harder.
Cheapest first thing is to listen to each injector with a $9 'mechanic's stethoscope'
see hear if each is clicking correctly and sound about the same.
Your could pull them and look at the tip orfices and also the 'catch screens' above for debris. (Have new replacement o-rings on hand.)
It might be simpler to go to a salvage yard and buy a set of 6 injectors off a 1993-1995 Magnum 3.9V6 that have low mileage.
At least one year the Chrysler original part number was listed as 4554127 for the 3.9V6 fuel injector but I am not completely sure that was the 1993-1995 version for the OBD-I system. After 1996 and the switch to OBD-II the V6 and V8 injectors are all the 'common calibration' 23.6 lbs/hr
Good luck with your troubleshooting.
