Equus 3140 - Scan Tool CanOBD2&1 Kit - Manual (Page 81)

CanOBD2&1 79
E
Ford OBD1 Systems
ADDITIONAL TESTS FOR EEC-IV SYSTEMS - CYLINDER BALANCE TEST
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 injec-
tor 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 18 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 Data Link
Connector (DLC) on page 68 for connector location.
Some DLCs have a plastic cover that must be removed before
connecting the CanOBD2&1 Scan Tool cable connector.
2. Connect the CanOBD2&1 Scan Tool
cable (with the Ford Connector Cable
Adaptor attached) to the CanOBD2&1
Scan Tool, then connect the adaptor to
the vehicle's DLC.
Press the
POWER/LINK button to turn the
CanOBD2&1 Scan Tool ON, then press
the ENTER/LD button to continue.
■ The Ford EEC-IV System menu displays.
Use the and buttons, as necessary, to make menu
selections.