Engine Controls - System/Component Tests - 3.8L: Introduction

1991 Mercury Cougar LS, 3.8 4SECTION Introduction

Prior to testing separate components or systems, it is recommended that all procedures listed in the BASIC TESTING article be performed. Since many computer controlled and monitored components will set a service code if they malfunction, check EEC-IV system and retrieve service codes. See Quick Test procedure in the appropriate TESTS W/CODES article in this section. If service codes are present see appropriate CIRCUIT TEST in the appropriate TESTS W/CODES article in this section.

NOTE: Testing individual components does not isolate shorts or opens. Perform all voltage tests with a Digital Volt-Ohmmeter (DVOM) that has a minimum 10-megohm input impedance, unless stated otherwise in test procedure. Use ohmmeter to isolate wiring harness shorts or opens.
RENDER: 1.0x

NO RELATED

Recommended Tools & Savings

Use the Manual With the Right Hardware

Pair factory procedures with proven DIY tools so the instructions are easier to execute.

Affiliate disclosure: We may earn a commission at no extra cost to you.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.