Innova 3120d, Руководство пользователя, Страница: 82 / 131

Ford OBD1 Systems
ADDITIONAL TESTS FOR EEC-IV SYSTEMS - CYLINDER BALANCE TEST
80 3120d
14. If a "pass code" (code 11 or 111) is
received, it indicates that the repairs
were successful and all the related
systems are working properly.
15. If a "pass code" (code 111 or 111) is not
received, the repair was unsuccessful.
Consult the vehicle's service manual
and recheck repair procedure.
ADDITIONAL TESTS FOR EEC-IV SYSTEMS
These tests are additional, supplemental tests, and are not
needed to retrieve Diagnostic Trouble Codes. Ford has
included them to further assist the technician / do-it-yourselfer
in the troubleshooting of vehicle problems.
Cylinder Balance Test (Vehicles equipped with Sequential
Electronic Fuel Injected (SEFI) systems only)
The Cylinder Balance Test assists in finding a weak or noncontributing
cylinder. The computer shuts off fuel (cuts off power to injectors) to each
cylinder, in sequence, and monitors for RPM changes (drop). Based on
this information, the computer determines if all the cylinders are
contributing power equally (for proper engine operation), or if some
cylinders are only contributing partially or not contributing at all.
SEFI Introduction
Sequential Electronic Fuel Injection (SEFI) belongs to a family of fuel
injection systems called "Multi-port/Multipoint Fuel Injection". Multi-port
(MFI) fuel injection systems contain one fuel injector per cylinder, and
the vehicle's computer electronically controls their operation. On some
multi-port fuel injection systems, the injectors all fire at the same time
and at every engine revolution. On other systems the injectors fire in
groups and/or at every other engine revolution. What distinguishes
Sequential Electronic Fuel Injection systems from other multi-port fuel
injection systems is that each injector is independently energized and
fires sequentially one after the other in the proper firing order. This gives
the vehicle's computer more control to cut the fuel to one injector at a
time (this can't be accomplished on the other systems because they fire
in groups of two ore more injectors).
Cylinder Balance Test Procedure
Check your vehicle thoroughly before performing any test. See
BEFORE YOU BEGIN on page 31 for details.
ALWAYS observe safety precautions whenever working on a
vehicle. Read and follow Safety Precautions on page 3 before
performing this test.
1. Locate the vehicle's Data Link Connector (DLC). See TEST
CONNECTORS on page 68 for connector location.