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 MANUALSCHEVROLET1985S10/T10 BLAZER 4WD L4-151 2.5LREPAIR AND DIAGNOSISPOWERTRAIN MANAGEMENTIGNITION SYSTEMIGNITION COILTESTING AND INSPECTION
1985 Chevrolet S10/T10 Blazer 4WD L4-151 2.5L
Ignition Coil: Testing and Inspection
1985 Chevrolet S10/T10 Blazer 4WD L4-151 2.5LSECTION Testing and Inspection
IGNITION COIL TEST
Connect ohmmeter. Test 1
Reading shouid be zero. or nearly zero. If not. replace coil.
Connect ohmmeter both ways. Test 2. Use high scale. Replace coil only if both readings are infinite.
If coil is good, go down to Pickup coil test.
PICKUP COIL TEST
On all distributors,including distributors with hall effect switch, remove rotor and pickup coil leads from module.
Connect ohmmeter test 1 and then test 2.
If vacuum unit is used, connect vacuum source to vacuum unit.Replace unit if inoperative.Observe ohmmeter throughout vacuum range; flex leads by hand without vacuum to check for intermittent opens.
Test 1- should read infinite at all times.
Test 2- should read steady at one value within 500-1500 ohm range.
NOTE:Ohmmeter may deflect if operating vacuum unit causes teeth to align.This is not a defect.
RENDER: 1.0x
NO RELATED
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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.