Problem Symptoms Table (For Your Information) - Mitsubishi 3000GT Service Manual

MULTIPORT FUEL INJECTION - Troubleshooting

PROBLEM SYMPTOMS TABLE (FOR YOUR INFORMATION)

Items
Won't star-l
(no initial combustion)
Starting
Fires up and dies
Hard starting
Hunting
Rough idle
Idling
Incorrect idle speed
stability
Engine stall (Die out)
Engine stall (Pass out)
Hesitation, Sag
Poor acceleration
Driving
Stumble
Shock
Surge
Knocking
Run-on (Dieseling)
Stopping
Fig. 1
,
Time
Symptom
The starter is used to crank the engine, but there is no combustion within
the cylinders, and the engine won't start.
There is combustion within the cylinders,
Engine starts after cranking a while.
Engine speed doesn't remain constant; changes at idle.
Usually, a judgement can be based upon the movement of the tachometer
pointer, and the vibration transmitted to the steering wheel, shift lever, body,
etc. This is called rough idle.
The engine doesn't idle at the usual correct speed.
The engine stalls when the foot is taken from the accelerator pedal,
regardless of whether the vehicle is moving or not.
The engine stalls when the accelerator pedal is depressed or while it is
being used.
"Hesitation" is the delay in response of the vehicle speed (engine speed)
that occurs when the accelerator pedal is depressed in order to accelerate
from the speed at which the vehicle is now traveling, or a temporary drop
in vehicle speed (engine rpm) during such acceleration. Serious hesitation
is called "sag". (Refer to Fig. 1)
Poor acceleration is inability to obtain an acceleration corresponding to the
degree of throttle opening, even though acceleration is smooth, or the in-
ability to reach maximum speed.
Engine rpm increase is delayed when the accelerator pedal is initially de-
pressed for acceleration from the stopped condition. (Refer to Fig. 2)
The feeling of a comparatively large impact or vibration when the engine
is accelerated or decelerated.
This is slight acceleration and deceleration feel usually occurred in steady,
light throttle cruise. Most notable under hight loads.
A sharp sound like a hammer striking the cylinder walls during driving and
which adversely affects driving.
Also called dieseling, this is a continued operation of the engine after the
ignition switch is turned off.
Hesitation
TSB Revision
then the engine soon stalls.
Fig. 2
Time