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 MANUALSCHEVROLET1990LUMINA APV V6-191 3.1LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTCOMPUTERS AND CONTROL SYSTEMSTESTING AND INSPECTIONINITIAL INSPECTION AND DIAGNOSTIC OVERVIEWFLOW OF DIAGNOSIS - START HERE
1990 Chevrolet Lumina APV V6-191 3.1L
Flow of Diagnosis - Start Here
1990 Chevrolet Lumina APV V6-191 3.1LSECTION Flow of Diagnosis - Start Here
Flow Of Diagnosis:
1. Get accurate description of complaint. Road test the vehicle to verify. Perform underhood inspection.
VISUALLY CHECK:
Vacuum hoses for splits, kinks and proper routing.
Ignition wires for cracking, hardness and proper connections at both the distributor and spark plugs.
All wiring for proper connections, pinches and cuts.
Wiring harness for proper routing.
Check for missing components.
2. Check TSB'S for manual updates, testing procedures, warranty and recall information.
3. If "CHECK ENGINE LIGHT OR SERVICE ENGINE SOON LIGHT" Is on, or codes other than code 12 are stored you must refer to Computerized Engine Controls section. This step also checks to see that the on-board diagnostics are working. If after correcting problem excessive emission levels still exist proceed to step 4.
4. If excessive emission levels or poor engine performance is related to emission control components or devices, and there is no "Check Engine" or "Service Engine Soon" light on see DIAGNOSIS BY SYMPTOM.
5. See DIAGNOSIS BY SYMPTOM under TESTING PROCEDURES for symptom vehicle is exhibiting. Follow procedures as outlined for given symptom.
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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.