Failing Emmissions Checklist

[WristPin]

If you are failing the emssions test, the print out they give you with the parameters, and your specs, together, will be helpful to determine the cause of your problem.

HC CO SYMPTOM CAUSES

High Normal Rough idle-------------------1. Faulty Ignition:
-----------------------------------------Incorrect timing, shorted or improperly gapped plugs,
-----------------------------------------Open (cracked) or crossed plug wires, Cracked distributor cap
-----------------------------------------2. Incorrect valve clearance
-----------------------------------------3. Leaky EGR valve
-----------------------------------------4. Leaky Exhaust valves
-----------------------------------------5. Leaky cylinder
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High Low Rough idle with fluctuating HC reading 1. Vacuum leak:
-----------------------------------------Vacuum hoses, Intake manifold, Intake chamber
-----------------------------------------PCV line, Throttle body
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High High Rough Idle with black smoke from exhaust 1. Clogged air filter
------------------------------------------2. Plugged PCV valve
------------------------------------------3. AS system problems
------------------------------------------4. Faulty EFI system:
------------------------------------------Faulty pressure regulator, Clogged fuel return line
----------------------------------------- Faulty air flow meter, Defective water temp sensor
----------------------------------------- Defective air temp sensor, Faulty ECU ( not typical)
----------------------------------------- Faulty injector, Faulty cold start injector