Pontiac Fiero 1988 Service Manual page 583

6E3-4 DRIVEABILITY AND EMISSIONS - FUEL INJECTION (PORT)
ALL NEW GENERAL MOTORS VEHICLES A R E CERTIFIED BY THE UNITED STATES
ENVIRONMENTAL PROTECTION AGENCY AS CONFORMING TO THE REQUIREMENTS OF THE
REGULATIONS FOR THE CONTROL OF AIR POLLUTION FROM NEW MOTOR VEHICLES. THIS
CERTIFICATION IS CONTINGENT ON CERTAIN ADJUSTMENTS BEING SET TO FACTORY
STANDARDS. IN MOST C A S E S , THESE ADJUSTMENT POINTS EITHER HAVE BEEN
PERMANENTLY SEALED AND/OR MADE INACCESSIBLE TO PREVENT INDISCRIMINATE OR
ROUTINE ADJUSTMENT IN THE FIELD. FOR THIS REASON, THE FACTORY PROCEDURE FOR
TEMPORARILY REMOVING PLUGS, CAPS, ETC., FOR PURPOSES OF SERVICING THE PRODUCT,
MUST BE STRICTLY FOLLOWED AND, WHEREVER PRACTICABLE, RETURNED TO THE
ORIGINAL INTENT OF THE DESIGN.
INTRODUCTION
GENERAL DESCRIPTION
This Section applies to engines which have a fuel
injector in the intake manifold near the intake valve
for each cylinder. It is commonly referred to as "Port
Fuel Injection".
These engines have controls to reduce exhaust
emissions, while maintaining good driveability and
fuel economy.
An Engine Control Module (ECM) is the heart of
this control system and has sensors used to provide
information about engine operation and the various
systems it controls. Details of basic operation,
diagnosis, functional checks, and on-vehicle service
are covered in Section C, Component Systems.
The ECM has the ability to do some diagnosis of
itself, and of other parts of the system. When it finds a
problem, it lights a "Service Engine Soon" Light on
the instrument panel and a trouble code will be stored
in the ECM memory. This does not mean that the
engine should be stopped right away, but that the
cause of the light coming on should be checked as soon
as reasonably possible.
DIAGNOSIS PROCEDURE
The following Sections(s) are written for specific
engine applications and are clearly indentified. Be
sure to use only the section which applies to the
engine family being diagnosed.
Before using this Section of the manual, you
should be familiar with the information and the
proper diagnosing procedures as described in Section
6E. If the proper diagnosis procedures are not
followed, as described in Section 6E, it may result in
unnecessary replacement of good parts.
Trouble Tree Charts incorporate diagnosis
procedures using an ALDL "Scan" tool, where
possible. The "Scan" tool has the ability to save time
in diagnosis and prevent the replacement of good
parts. The key to using the "SCAN" tool
successfully for diagnosis lies in the technician's
ability to understand the system he is trying to
diagnose, as well as an understanding of the
"SCAN" toot's limitations. See Section 6E for
more information.