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.
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HOMESERVICE MANUALSCHEVROLET1987SUBURBAN R20, 5.7 K, STANDARDREPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCESYSTEMCCC TBI TESTS W/CODESDIAGNOSTIC CHARTSCHART A3 - ENGINE CRANKS, BUT WILL NOT RUN (2.5L)TEST DESCRIPTION
1987 Chevrolet Suburban R20, 5.7 K, Standard
Test Description
1987 Chevrolet Suburban R20, 5.7 K, StandardSECTION Test Description
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- "SERVICE ENGINE SOON" light on is basic check for ignition and battery supply to ECM. No "ALDL" may be due to an ECM problem. CHART A2 will diagnose the ECM. If TPS is over 2.5 volts, engine may be in "clear flood" mode, that will cause starting problems. If coolant sensor is below -22°F (-30°C), ECM will provide fuel for extremely cold temperatures that will completely flood engine.
- Check voltage at spark plugs with ST-125 (J-26792). No spark indicates basic ignition problem.
- While cranking engine, there should be no fuel spray with injector disconnected. Replace injector if it sprays or drips excessively.
- Using Injector Test Light (J-34730, BT-8329A), test injector circuit. A blinking light indicates ECM is controlling injector.
- This determines if fuel pressure is present at injector and that injector is operating properly.
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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.