I have 96 Dakota 3.9 automatic that gives me less fuel mileage than
what I believe I should be getting.
I have ensured that the plugs are in good shape,the plug wires are
new, tires properly inflated, drive with a light foot, I have changed
both oxy sensors. The truck runs fine and the OBD II is not
generating any trouble codes. The truck recently passed the Calif
smog test and passed by a very wide margin. I have ran liquid
injector cleaner in the tank several times.
I obtained a Davis CarChip device so I could get a printed record of
what is happening in regard to OBD readings. What I found out is that
Fuel System #2 runs in open loop for a few minutes while the coolant
temp is coming up, but Fuel System #1 is staying in open mode all the
Now I am an OLD shade tree hobby mech since Model A Fords were a
common sight on the streets. Until now I haven't given much effort
to understanding the OBD system but I now would like to increase my
knowledge in that area, hence putting out the bucks for the Davis
My guess, and correct me if I am wrong, is that Fuel System #1 refers
to the injectors on Bank #1 and Fuel System #2 refers to the injectors
on Bank 2. Can anyone confirm this.
Would a dirty or clogged injector in Bank #1 cause it to remain in
Open loop? Is now the next logical step to have a professional
cleaning of the injectors.