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1986-95 Ford V8 Truck Speed Density EEC-IV Pinout Wiring Diagram
Reference · 1987-1991 BroncoAll 175 wiring diagrams
Wiring diagram for a 1986-95 speed-density V8 truck mapping engine sensors, injectors, and EEC pins with circuit numbers.
Part of 1987-1991 Ford Bronco Wiring Diagrams
This document is a wiring/pinout schematic for the Ford EEC-IV Speed Density fuel injection system as used on 1986-95 V8 trucks. It shows connector drawings and EEC processor pin assignments for the main engine sensors and actuators: Engine Coolant Temp sensor (ECT, pin 7), Air Charge Temp sensor (ACT, pin 25), Throttle Position Sensor (TPS, pin 47), Manifold Absolute Pressure sensor (MAP, pin 45), Vehicle Speed Sensor (VSS+, pin 3; VSS-, pin 6), and Exhaust Oxygen sensor (HEGO, pin 29). It also identifies signal return (SIG RTN 46), reference voltage (VREF 26), Neutral Drive Switch (NDS 30, auto trans only, with man trans grounding), fuel pump monitor (FPM 8), self-test connector (STO/MIL 17), self-test input (STI 48), and the check engine light (MIL). Injector bank wiring is shown: cylinders 1, 4, 5 and 8 on INJ 58 and cylinders 2, 3, 6 and 7 on INJ 59. The idle air bypass (IAB/ISC) is on pin 21. Grounds are listed: CASE GND 20, PWR GND 40, HEGO GND 49, PWR GND 60, tied to the battery. Power feeds come through the EFI relay to VPWR pins 37 and 57. Useful for diagnosing sensor circuits and tracing EEC-IV wiring on speed-density Ford trucks.
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Frequently asked questions
- What EEC pin is the MAP sensor on for a 1986-95 speed density Ford V8 truck?
- The Manifold Absolute Pressure (MAP) sensor signal goes to EEC pin 45, with VREF on pin 26 and signal return (SIG RTN) on pin 46.
- Which injectors are on each injector driver bank?
- Cylinders 1, 4, 5, and 8 are on INJ pin 58; cylinders 2, 3, 6, and 7 are on INJ pin 59.
- What pins are the Vehicle Speed Sensor wires connected to?
- VSS+ connects to pin 3 and VSS- connects to pin 6, with a ground shown at the sensor circuit.
- What are the ground pins on the EEC-IV computer in this schematic?
- CASE GND pin 20, PWR GND pin 40, HEGO GND pin 49, and PWR GND pin 60, all tied to the battery negative.
- Where does the EEC-IV get power in this diagram?
- Power comes from the battery through the EFI relay to VPWR at EEC pins 37 and 57.
- What is pin 30 (NDS) used for?
- NDS pin 30 is the Neutral Drive Switch input for automatic transmissions only; on manual transmissions it is wired differently (shown grounded on the auto trans side).
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