It might be the thermostat. I've seen them stick open so that the engine
stays cold. A cold engine will require more fuel and the SEBC will ensure a
richer mixture to a cold engine, and that could be killing your MPG.
One thing to check is the codes that are set in the SEBC. The computer will
set a code if it does not reach acceptable closed loop temperature mode.
Unless you have California emissions, it will not turn on the check engine
light when it sets the code.
You do not need an OBD-II scanner to check the codes on ANY Chrylser
vehicles. Simply turn the ignition switch ON OFF ON OFF ON in rapid order
(in a 5 second timeframe) and watch either the check engine light , or on my
97 Dakota, the codes will show up in the odometer liquid crystal readout.
For check engine lights on earlier models, the light will blink the codes.
For example: blink blink blink pause blink blink is code 32. The tests
will always conclude with code 55. If you've disconnected the battery
recently you will also see a code 12.
According to my 97 Dakota shop manual code 17 should be present if it is not
coming up to temperature properly (Code 17 = engine is cold too long). On
older models, it might be code 18. My wife used to have a 90 Dodge Spirit
(now my Mama's car), and the thermostat stuck open. The heater would barely
put out any heat, the gas mileage went to hell, and when I did a check of
the codes, code 18 was present. I replaced the thermostat and that fixed
it.
Hope this helps.
Mike Satterfield
Round Rock TX
97 Dakota SLT+ CC, 5.2L, 4spd Automatic, Mopar Headers, Flowmaster split
single
dual Exhaust, , 9" K&N open air cleaner. Now with a new 4.10 LSD, Lakewood
Traction Bars, and 4 new BF Goodrich Radial T/A tires!
This archive was generated by hypermail 2b29 : Fri Jun 20 2003 - 11:46:59 EDT