Jim Grant's Tech Tips
'95 Dodge Neon, Check Engine Light On after Bath
have a 95 Dodge Neon with about 97k miles on it. We are selling
the vehicle and I cleaned the engine with engine cleaner that you can
buy at an auto parts store. After cleaning and rinsing it off, the car
was really running fast. I took it around the block a few times and the
idle came back down. The next day we went out to start the car and it
was running rough and the check engine light came on. I never had a problem
with the light before we cleaned the engine. Could the cleaning solution
and the water have shorted out a sensor or something?
Yes, it is very likely
that the bath you gave the engine has created some undesirable consequences.
With the information youve provided I would be first prone to inspect
the ignition/spark plug wires. Check closely where the spark plug wires
connect to the spark plugs. The way your engine is designed, it is easy
for water, and in your case cleaner too, to become trapped in the spark
plug pockets/holes. The water, especially with some cleaner and oil, will
provide an alternative path for the spark that is suppose to go to the
spark plug. The result can be a rough running engine which causes the
check engine light to come on. If inspection does find a water problem
youll have to remove the water and wipe, dry and clean the ends
of the spark plug wires that were soaking in the conductive solution.
If the repair was affective the engine will smooth right out and run fine.
The check engine light on the other hand will still be on. If everything
is right, in a day or so of driving, the check engine light will go out.