Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
1989 Isuzu I-Mark LSFACTORY OEM SERVICE PROCEDURE
Fuel Injectors
- Unplug fuel injector harness at injector and measure resistance across terminals. All injectors must have 2-3 ohms of resistance. If resistance is not within specification, replace fuel injector.
- With engine running, check fuel injector operating noise. Normal operation of injectors is indicated when a regular "click" is heard, which varies with engine speed. If "click" is not heard, replace injector.
- Check fuel injectors for leakage. Remove all injectors with fuel hose connected. Check for injector leakage by operating fuel pump with battery voltage applied directly to fuel pump relay terminal (Red/Blue on I-Mark).
- On I-Mark, fuel pump relay is located on right side of engine compartment, on firewall.
- Leakage should be less than 2 drops per minute. If leakage exceeds limit, replace fuel injector.
Factory Service Tools
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.