This page is about 1996-2004 Mustang 4.6L Air EFI systems.

If you would like to learn how to build your own EFI harness you will need to know:
How to Solder
What Wire Sizes to Use
How Relays Work
How the EEC Computer Connector Comes Apart
Then study the wiring diagrams, computer pin out charts, and assemble your own harness.

If you want to purchase a BRAND NEW EFI harness or buy parts for your harness project;
Please visit our PRODUCTS PAGE

PIN	1996-98 4.6L	1999-04 4.6L
1		Coil on Plug #6
2	MIL
3		GND
13	DLC PWR pin 13	DLC PWR pin 13
15	DLC (-) pin 10	DLC (-) pin 10
16	DLC (+) pin 2	DLC (+) pin 2
21	Crank Sensor (+)	Crank Sensor (+)
22	Crank Sensor (-)	Crank Sensor (-)
23		L Knock Sensor (-) (DOHC only)
24	GND
25	GND	GND
26	Coil #1 (cyl 1 & 6)	Coil on Plug #1
27		Coil on Plug #5
32	L Knock Sensor (DOHC only)	R Knock Sensor (-) (DOHC only)
33	GND
36	MAF RTN	MAF RTN
38	ECT	ECT
39	ACT	ACT
40	FPM	FPM
46	E-Fan High	E-Fan High
48	Tach
51	GND	GND
52	Coil #2 (cyl 3 & 5)	Coil on Plug #3
53		Coil on Plug #4
55	KAM PWR	KAM PWR
57	R Knock Sensor (DOHC only)	R Knock Sensor (+) (DOHC only)
58	VSS
60	R HEGO	R HEGO
68		VSS
71	PWR	PWR
72	Injector #7	Injector #7
73	Injector #5	Injector #5
74	Injector #3	Injector #3
75	Injector #1	Injector #1
76	GND
77	GND	GND
78	Coil #3 (cyl 4 & 7)	Coil on Plug #7
79		Coil on Plug #8
80	FP Relay	FP Driver
83	IAB	IAB
85	CAM Sensor	CAM Sensor
87	L HEGO	L HEGO
88	MAF	MAF
89	TPS	TPS
90	V-REF	V-REF
91	SIG-RTN	SIG-RTN
93	RF HEGO Heater GND	RF HEGO Heater GND
94	LF HEGO Heater GND	LF HEGO Heater GND
97	PWR	PWR
98	Injector #8	Injector #8
99	Injector #6	Injector #6
100	Injector #4	Injector #4
101	Injector #2	Injector #2
102		L Knock Sensor (+) (DOHC only)
103	GND	GND
104	Coil #4 (cyl 2 & 8 )	Coil on Plug #2

4.6L EFI Ingition Circuits:

4.6L EFI Harness Power circuit:

	EFI Relay 1	EFI Relay 2	Fuel Pump Relay	Fan Relay	WOT Relay
Pin 30	Constant +12 Volts from Battery protected by Fuse
Pin 85	Ground	Ground	EEC Pin 80	EEC Pin 46	EEC Pin 69
Pin 86	+12 Volts from Ignition Switch (Hot in Run and Start)
Pin 87	EEC 71/97 Ck Engine Light Fuel Injectors Idle Air Bypass	Ignition Coils MAF Sensor HEGO Sensors Alternator	Fuel Pump FPM (EEC Pin 40)	Electric Fan	-
Pin 87a	-				A/C Compressor

Data Link Connector:

Automatic Transmission: