Hyundai has had its share of no-power complaints. Most of these complaints are on older models with high mileage. Oftentimes, these problems will lead to a plugged catalytic converter. It’s not unusual that the first symptom the customer gets with a plugged converter is a no-start problem. Diagnosing this problem on a Hyundai can be a little trickier than on other nameplates. Normally, you would expect a plugged exhaust to always be plugged. Sure, they will get worse as they heat up, but the problem is usually easy to pick up on a road test. But the converter on a Hyundai will fail and the catalyst will break up into pieces, caused by the effect of heat and the exhaust gases, and will fill the outlet of the converter shell and block the exhaust almost completely.


The first one we saw was a diagnostic challenge. If you suspect a problem with the catalytic converter, don’t forget that it’s right under the exhaust manifold. Remove the O2 sensor to access pre-converter exhaust gases to either test the pressure or provide a path for the gases. If you get one of these cars in and detect that it has wet spark plugs with good spark, yet it won’t fire even after the cylinders have been dried out and the new plugs have been installed, the next thing I would check is the exhaust.


Be sure to also check the motor oil, since it likely needs to be changed. It may have to be done as part of the drying-out process. Depending on how long the customer tried to start the car, the crankcase may have quarts of gas mixed in with the oil. Even if the crankcase isn’t overfilled, always recommend the oil change.