Factory Five Racing Mk3 Roadster Assembly Manual page 273

1983-98 19 Tooth Pink
1983-98 20 Tooth Black
1983-98 21 Tooth Red
1983-98 23 Tooth White
Mass Air Sensor
Mass air sensors are devices used to measure air flow into the engine for the vehicles computer. These
started to be used in Mustangs in 1989 and are still being used.
1986-1988 engines measured air pressure in the intake to provide information for the computer. Mass air
sensors send more accurate information to the computer than speed density sensors. A speed density
('86-88) controlled vehicle can be converted to mass air by changing the computer, adding the sensor, and
running 4 wires (two to the computer, one positive, and one ground). There is a flexible rubber elbow
that connects the mass air meter to the throttle body, which is required for use in a Factory Five kit.
When a 1996-2003 Mustang is used as a donor for a Roadster kit, the stock air filter and filter box are
required to complete the kit.
Oxygen Sensors
Oxygen sensors are placed in the exhaust to measure the oxygen content of the exhaust. This
measurement is used by the computer to determine whether fuel delivery to the engine needs to be
increased or decreased. From 1986-1995 Ford Mustangs used two oxygen sensors, one in each side of the
exhaust system. From 1996-2004 Mustangs used four oxygen sensors, two per side. At full throttle the
oxygen sensor signals are not used by the computer, because the computer has a built in program to run
the engine rich at wide open throttle. Oxygen sensors will usually be most effective when placed near the
collection point of headers because the exhaust will remain very hot, and an average measurement of all
of the cylinders can be taken. All oxygen sensors are recommended to be used when placing a fuel
injected motor into a Factory Five kit, however in the 1996-2004 models with 4 oxygen sensors, it is
suggested to purchase a by pass kit to eliminate two of the sensors. This can also be done with
modifications to the wiring harness.
Exhaust headers
1986 to 1993 Mustang headers have 1.5" tubes, and remained the same shape. From 1994 to 1995
Mustang headers still have 1.5" headers, but the collector flanges have a larger ball and socket joint.
1996 to 2004 Mustangs used cast exhaust manifolds. SOHC engines had circular exhaust ports, and the
DOHC had oval ports; however the collector flange changed in 2003 and 2004. Factory Five Produces J-
pipes to connect stock Mustang headers in a reversed position to Roadster 4 port side pipes for the
following years: 1986-1995, 1996-2004. 4 into 4 headers are also available from Factory Five for the
following applications: pre 1995 289/302, 96-04 SOHC 4.6L, 96-04 DOHC 4.6L, 351W, 390/427/428
big blocks, and 429/460 big blocks. For those installing 351 Windsor engines there are a few companies
including Ford Motorsport that carry exhaust headers for the installation of a 351 Windsor into a 1986-
1993 Mustang. These headers will work with Factory Five 1986-1995 J-pipes.
A Flexible exhaust hanger is a required donor part used to hang the side pipes on a Factory Five kit, and
can be found on almost any Mustang since the 80's.
Upper and lower radiator hoses
C0DZ-00017271-B
C1DZ-00017271-A
C40Z-00017271-A
E6MS-0017271C-M
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