Chevrolet Light Duty Truck 1973 Service Manual page 337

Engine Tune-Up................................................................... 6-1
Theory of Operation.......................................................... 6-14
Engine Mechanical (In Line)......................................... 6-19
General Description................................................ ...........
Mechanical Checks and Adjustments............... ...........
Spark Plug Removal............................................ ..........
Test Compression................................................... ...........
Service and Install Spark Plugs....................... ..........
Service Ignition System....................................... ...........
Service Battery and Battery Cables................ ........... 6-3
Service Delcotron and Regulator..................... ........... 6-4
Service Belts............................................................ .......... 6-5
Service Manifold Heat Valve............................ .......... 6-5
Tighten Manifold................................................... .......... 6-5
Service Fuel Lines and Fuel Filter................ .......... 6-5
Service Cooling System....................................... ........... 6-5
Service Crankcase Ventilation........................... ...........
Service Air Injection Reactor System............. ..........
The engine tune-up is important to the modern
automotive engine with its vastly improved power and
performance. Emission system requirements, interrelated
system functions, improved electrical systems and other
advances in design, make today's engines more sensitive
and have a decided effect on power, performance and
fuel consumption.
It is seldom advisable to attempt a tune up by correction
of one or two items only. Time will normally be saved
and more lasting results assured if the technician will
follow a definite and thorough procedure of analysis and
correction of all items affecting power, performance and
economy.
The tune-up will be performed in two parts. The first
part will consist of mechanical checks and adjustments;
the second part will consist of an instrument checkout
MECHANICAL CHECKS A N D ADJUSTMENTS
SPARK PLUG REMOVAL
Remove any foreign matter from around spark plugs by
SECTION 6
ENGINE
CONTENTS OF THIS SECTION
Engine Mechanical (V
Diagnosis.................................................................................
Special Tools......................................................................... 6-73
ENGINE TUNE-UP
INDEX
Choke Adjustment.......................................................... ... 6-7
6-1
Instrument Check-Out..................................................... ...
6-1
Instrument Hook-Up..................................................... ...
6-1
Check and Adjust Dwell.............................................. ...
6-2
Check Dwell Variation................................................. ...
6-2
Check and Adjust Timing........................................ ...
6-2
Adjust Idle Speed.......................................................... ... 6-9
Additional Checks and Adjustments......................... ...
Cylinder Balance Test................................................... ...
Battery................................................................................ ...
Ignition.............................................................................. ...
Carburetor......................................................................... ... 6-13
Fuel Pum p........................................................................ ... 6-13
Cooling System........................................................ ....... ... 6-13
6-6
Cylinder Head Torque and Valve Adjustment ... 6-13
6-6
GENERAL DESCRIPTION
that can be performed with any one of the units of
service equipment available for this purpose. Always
follow the instructions provided by the manufacturer of
the particular equipment to be used.
Additional checks and adjustments are included in the
latter part of this section for use as required. Many of
these operations can be used to isolate and correct
trouble located during the tune-up. Where conditions are
uncovered requiring major corrective action, refer to the
appropriate section of this manual or the Overhaul Manual
for detailed service information.
Typical illustrations and procedures are used except
where specific illustrations or procedures are necessary to
clarify the operation. Illustrations showing bench
operations are used for clarification, however, all
operations can be performed on the vehicle.
blowing out with compressed air, then disconnect wires
and remove plugs. To disconnect wire at spark plug,
grasp the boot portion of the wire and apply only
).................................................... 6-44
8
LIGHT DUTY TRUCK SERVICE MANUAL
6-68
6-8
6-8
6-8
6-8
6-8
6-11
6-11
6-11
6-11