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2.9 to 5.0 Wiring Harness Conversion


Dmgctrl88

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So I've been on here quite a bit and I currently have a build thread going. I'm almost done building my motor and was looking ahead to my next task to overcome.

So some basic details before going in about my build. 86' 2.9 A4LD 4x4 converting to an 5.0 & C4 retaining the original BW1350 transfer case. I haven't gotten a computer yet, but my equipment looks to be 87' speed density stuff.

From what I have seen here, most folks swap in a new wiring harness when doing the swap. What I haven't seen yet; Has someone tried to convert their existing 2.9 EFI harness to the 5.0 EFI? :icon_confused:

Both harnesses seem to have the 60 pin connector at the computer. I haven't taken my 2.9 harness out of the truck yet, and this will allow me to keep the original harness where it is without having to poke out grommets or holes in my firewall.

A buddy of mine seems to think it can be done, and it would save me some extra money. Basically just strategically swap wires at the 60 pin connector to best match the 5.0 computer and then route the wires to the sensors and actuators with new connectors.
 


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Dmgctrl88

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I have found some information regarding the conversion of the existing harness. They are not linked but as you will see, both diagrams are similar.

First the 2.9



1 Yellow/Black Keep-Alive Power
2 Light Green Brake on-off (BOO)
3 Dark Green/White Vehicle Speed Sensor (+)
4 Dark Green/Yellow Ignition Diagnostic Monitor
5 Red/Light Green Ignition Power (Switched) ????????????
6 Black/White Vehicle Speed Sensor (-)
7 Light Green/Yellow Engine Coolant temperature Sensor
8 Orange/Light Blue Fuel Pump Monitor
9 ---------- ----------
10 Tan/Yellow A/C Compressor Clutch
11 ---------- ----------
12 ---------- ----------
13 ---------- ----------
14 ---------- ----------
15 ---------- ----------
16 Black/Orange Ignition Ground
17 Tan/Red Self Test Output and "Check Engine"
18 ---------- ----------
19 ---------- ----------
20 Black Case Ground
21 Gray/White Idle Speed Control (Bypass air)
22 Tan/Light Green Fuel Pump
23 ---------- ----------
24 ---------- ----------
25 Light Green/Purple Air Charge Temperature
26 Orange/White Reference Voltage
27 ---------- ----------
28 ---------- ----------
29 Dark Green/Purple Heated Exhaust Gas Oxygen Sensor
30 White/Black Neutral Drive Switch (Automatic)
-OR- White/Black Neutral Gear/Clutch Engage Switch (Manual)
31 ---------- ----------
32 ---------- ----------
33 ---------- ----------
34 ---------- ----------
35 ---------- ----------
36 Yellow/Light Green Spark Out, Timing Control (Spout)
37 Red Vehicle Power
38 ---------- ----------
39 ---------- ----------
40 Black/Light Green Power Ground
41 ---------- ----------
42 ---------- ----------
43 ---------- ----------
44 ---------- ----------
45 Dark Blue/Light Green Manifold Absolute Pressure (MAP)
46 Black/White Signal Return
47 Dark Green/Light Green Throttle Position Sensor
48 White/Red Self-Test Input
49 Orange Heated Exhaust Gas Oxygen Sensor (-)
50 ---------- ----------
51 ---------- ----------
52 Tan/Light Blue Shift Solenoid ¾
53 ---------- ----------
54 Red Wide-Open-Throttle A/C Cutoff
55 Tan/Yellow A/C Compressor Clutch
56 Dark Blue Profile Ignition Pickup (PIP)
57 Red Vehicle Power
58 Light Green/White Injector Bank 1
59 Tan/Red Injector Bank 2
60 Black/Light Green Power Ground

Second, the 5.0



01 YEL +12 Battery Voltage 12-14 volts
03 DG/WHT VSS + / Vehicle Speed Sensor Positive 55MPH = 125hz
04 DG/Y IDM / Ignition Diagnostic Monitor (TFI) 20-31hz
06 ORG/YEL VSS – / Vehicle Speed Sensor Negitive 55MPH = 125hz
07 LG/RED ECT / Engine Coolant Temp Sensor 0.5 volts = 200*F
09 TAN/BLU MAF RTN / Mass Air Flow Return < 0.1volts
12 BRN/YEL Fuel Injector 3 4.9-5.2ms duty cycle
13 BRN/BLU Fuel Injector 4 4.9-5.2ms duty cycle
14 TAN/ORG Fuel Injector 5 4.9-5.2ms duty cycle
15 LG/ORG Fuel Injector 6 4.9-5.2ms duty cycle
16 BLK/ORG Ignition Ground (TFI)
17 TAN MIL / Engine Light & STO / Self-Test Output ON = GND
19 DG/YEL FPM / Fuel Pump Monitor Pump on = 12-14volts
20 BLK Ground < 0.1volts
21 WHT/BLU IAB / Idle Air Bypass 3.0 – 12.0 volts
22 BLU/ORG FPR / Fuel Pump Relay ON = GND
25 GRAY ACT / Air Charge Temp Sensor 3 volts = 70*F
26 ORG/WHT Voltage Reference 4.9-5.1 volts
29 DK GRN Right HEGO 0.0-1.0 volts
30 BLU/YEL Transmission Neutral Interface 0.0 volts in neutral
36 YEL/LGRN SPOUT / Spark Output Signal (TFI)
37 RED EEC Relay +12 volts 12-14 volts
40 BLK Ground < 0.1 volt
42 TAN/RED Fuel Injector 7 4.9-5.2ms duty cycle
43 DK BLU Left HEGO 0.0-1.0 volts
45 GRN/BLK BP / Barometric Pressure Sensor 159hz = sea level
46 GRY/RED Signal Return 0.1 volts
47 DK GRN TPS / Throttle Position Sensor 0.9 volts
48 TAN/RED STI / Self-Test Input GND = Self-Test
49 ORG Ground < 0.1 volt
50 BLU/RED MAF / Mass Air Flow Sensor 0.8 volts
52 LT BLU Fuel Injector 8 4.9-5.2ms duty cycle
56 DK BLU PIP / Profile Ignition Pickup (TFI)
57 RED EEC Relay +12 volts 12-14 volts
58 TAN/RED Fuel Injector 1 4.9-5.2ms duty cycle
59 TAN/ORG Fuel Injector 2 4.9-5.2ms duty cycle
60 BLK Ground < 0.1volt
 

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I have not done this personally, but I know of people who have done it, and it can be done.

The biggest part is re-pinning the PCM connector to match the 5.0 computer. Then you just have to add a pair of injector wires, and stretch a few things to reach the new location of the sensor.
 

Dmgctrl88

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You are right. I am playing mix and match on notepad between the two different harnesses and found that all but 11 wires need to be changed. 2-3 need to be added to accommodate more injectors.

Basically I have to convert/add to the following pins on my 60 pin connector inside the cab:

9 Mass Air Flow Return
12 Fuel Injector 3
13 Fuel Injector 4
14 Fuel Injector 5
15 Fuel Injector 6
19 Fuel Pump Monitor
42 Fuel Injector 7
43 Left Hego
45 Barometric Pressure
49 Ground
50 Mass Air Flow Sensor ??? Might not use due to Speed Density ???
52 Fuel Injector 8
58 Fuel Injector 1
59 Fuel Injector 2

Since I have speed density equipment at the moment, I might be able to get away with all of my existing wires at the moment.
 


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