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Forum > Failed Smog Test > Question

1987 Toyota Camry 1987 Failed for High HC Twice

Hello. My Toyota Camry 1987 2 liter gas engine failed the smog check twice in a row for high hydrocarbons (HC) @ 162. Max allowed was 120. After having it fixing with a mechanic it failed @ 355 hydrocarbon at idle. Now my Camry is a gross polluter.

The smog test center informed me that previous owner had already tried to smog check it failed for exactly the same reason and at the exact same levels. I took my car to reputable and experienced mechanic and he changed oil and oil filter, cleaned air filter, checked spark plugs and wires and checked distributor cap. We also replaced the oxygen sensor (O2) with an aftermarket sensor, plus I put on a new gas cap.

Before the test I also added "guaranteed to pass smog" fuel additive and followed directions adding to full tank of fuel driving for whole tank and refilling with 91 octane fuel before retest and lowered idle.

I took it in for the smog test and had tested again, this time the results were worse and my Camry is now a gross polluter. I want to know how this could happen. Is there foul play? Do you think that new O2 sensor could be faulty? Do you think there is foul play from either mechanic or smog technician. I just bought the car and have paid all dmv fees, plus purchase price, plus two smog test payments, plus repair costs. I am into this vehicle for about $1500 now. Any ideas? Please help.


Answer:

Your mechanic has already checked for the main problems which cause high HC, which are ignition related, i.e. spark plugs, wires, distributor and cap and rotor. Have they checked engine compression? If engine ignition is good and the air/fuel mixture is correct, we recommend ensuring engine compression is normal also. Without proper compression your Toyota Camry's engine will not ignite the air/fuel mixture properly.

Next, it is very important to diagnose CO emissions. If your engine is producing low CO (along with high HC) we'd consider looking into faults which would cause lean fuel mixtures. If CO is high (accompanied by high HC) we'd consider faults which would cause a rich fuel mixture.

The oxygen sensor, along with various engine emission sensors, are responsible for allowing the engine control computer to deliver the correct amount of fuel to the amount of air entering the intake manifold.

A thorough diagnosis should reveal the fault(s) which are causing your Toyota Camry to produce high HC. Diagnosing CO levels is an important part of the overall repair process.

Furthermore, we recommend only using the gas octane level required for your vehicle which should be 87 Octane. Using a higher octane only assists in situations where NO levels are high, and will usually lower NO but raise HC and CO. Only use the recommend octane level for your vehicle.

As far as foul play... on an older model vehicle which has failed the smog test we can not suspect foul play. It is very common for a vehicle with high mileage and/or wear and tear, to develop problems which will need to smog test failure.

To learn more about high emissions and smog check failures please visit this page.


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