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Test KP - Introduction

NOTE: This Pinpoint Test has been revised as per Ford TSB 91-11B-6.
NOTE: Enter this test when directed here by a driveability symptom. This test is intended to diagnose only the following systems or components:
Fig 1: Octane Adjust Circuit
G90D13154
OCTANE ADJUST SHORTING BAR LOCATIONS

Application Location
2.3L PFI (Truck) Passenger side inner fender, taped to self-test connector.
4.0L (Aerostar) Drivers side engine cowl, near w/wiper motor and MAP
4.0L (Bronco II & Ranger) Passenger side of fender apron, taped to self-test connector.
TEST PIN WIRE COLOR IDENTIFICATION

Application (Test Pin No.) Wire Color
Pins 18, 43 or 44 (OCT ADJ)
2.3L (Ranger) Black/White
4.0L (Aerostar) Orange
4.0L (Ranger) White/Red
Pin 46 (SIG RTN)
4.9L, 5.0L & 5.8L (Bronco & F-Series), 7.3L Diesel & 7.5L (F-Series) Gray/Red
All Others Black/White

To assure compliance with Federal Emission Standards (EPA), use a higher octane grade of fuel to address the spark knock concern. DO NOT  remove the Octane Adjust Shorting Bar unless you have been directed by an application specific Technical Service Bulletin.

The purpose of the Octane Adjust Shorting Bar is to provide optimum spark advance for the fuel being used. Removing the Bar retards spark advance about 3 to 4 degrees.