Jim Grant's Tech Tips
'93 Mitsubishi Eclipse, Forever Hard Starting
Q:
First thing in the morning it takes forever to start my ‘93 Mitsubishi
Eclipse. It turns over, but won't stay running. I have to keep cranking
and cranking and finally it will stay running, it idles rough until after
you've driven it for awhile. Someone told me it was the thing that heats
the fuel to make it expand. What do you think and if you agree; what is
that part called? Sheri Collier
A:
The thing that
makes the fuel expand? I don’t think so. A vehicle that starts hard
when cold but runs good warm, makes me think of a sensor problem. When
an engine is cold, additional fuel is needed to start the engine and to
allow for good driveabilty while the engine warms up. In the old days
this was called a choke. For today’s computerized vehicles it’s
called a coolant temperature sensor. The job of this sensor is simple,
it alters a voltage signal to the computer in relationship to the temperature
of the coolant. These sensors can break/fail and in most cases result
in a check engine light. The problem occurs when the sensor shifts its
values, it goes out of calibration. This means the sensor is lying. The
computer doesn’t know any better. The result is the incorrect amount
of fuel to start and run the engine. Diagnosis is best done when the vehicle
is cold. Your tech should have no problem proving if your computer thinks
it’s in the tropics while there’s still ice on the pond.
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