Transcript Common Starting System Problems

Common
starting
system
problems

In a no-crank problem, the engine
crankshaft does NOT rotate properly with
the ignition key at start. The most common
causes are a dead battery, poor electrical
connection, or faulty system component.

A slow cranking condition occurs when the
engine crankshaft rotates at lower than
normal speed. It is usually caused by the
same kind of faults producing a no-crank
problem.

A buzzing or clicking sound from the
solenoid, without cranking, is commonly
due to a discharged battery or poor battery
cable connections. Low current flow is
causing the solenoid plunger to rapidly kick
in and out, making a clattering sound.

A single click sound, without cranking,
may point to a bad starting motor, burned
solenoid contacts, dead battery, or engine
mechanical problems. The click is usually
the solenoid closing or the pinion gear
contacting the flywheel gear.

A humming sound, after momentary
engine cranking, may be due to a bad starter
overrunning clutch or worn pinion gear unit.
Pinion gear wear can make the gear
disengage from the flywheel gear too soon.
This can let the motor armature spin rapidly,
with a humming sound.

A metallic grinding noise may be caused
by broken flywheel teeth or pinion gear
teeth wear. The grinding may be the gears
clashing against each other.

Normal cranking, without starting, is
usually NOT caused by the starting system.
There may be trouble in the fuel or ignition
systems. With a diesel engine, check engine
cranking speed. If cranking rpm is low, the
diesel may not start.

Sometimes the starting solenoid feeds
current to the ignition system after engine
starting. If the engine starts and then dies
(stops running) as the ignition key is
released, check voltage from the solenoid to
the ignition system. You could have an open
wire or connection in the solenoid circuit. A
defective ignition switch or wiring problem
are other possible causes.
The End

This information is taken from the text book
Modern Automotive Technology by James
Duffy. You must read it if you want to learn
about cars there is a lot of info in this book.

Mr. Salisbury, author of powerpoint.