What are the symptoms of a car without a catalytic converter?
4 Answers
The symptoms of a car without a catalytic converter are: shortly after the vehicle starts, a noticeable red burning phenomenon occurs from the exhaust manifold to the catalytic converter, and a hissing sound of air leakage and gurgling noise can be heard when accelerating. Below is relevant information about automotive catalytic converters: 1. Working principle: When high-temperature exhaust gases pass through the purification device, the purifying agent in the catalytic converter enhances the activity of CO, HC, and NOx gases, promoting certain oxidation-reduction chemical reactions. CO oxidizes into colorless, non-toxic carbon dioxide gas at high temperatures. HC compounds oxidize into water (H2O) and carbon dioxide. NOx is reduced into nitrogen and oxygen. These three harmful gases are converted into harmless gases, thereby purifying the vehicle's exhaust. 2. Inspection method: Check whether the catalytic converter is damaged or overheated during driving. After lifting the vehicle, observe the surface of the catalytic converter for dents. If there are obvious indentations or scratches, it indicates that the carrier of the catalytic converter may be damaged.
Yesterday I drove my neighbor's old Bora with the catalytic converter removed. The most obvious issue was the extremely pungent exhaust smell, like a mix of burnt rotten eggs and gasoline. At traffic lights, drivers next to me rolled up their windows. The check engine light on the dashboard stayed on constantly, and fuel consumption was unusually high—a full tank lasted 80 kilometers less than usual. It would definitely fail the emissions test during the annual inspection. The mechanic said running it like this long-term would cause carbon buildup and damage the engine. The exhaust pipe also kept making metallic rattling noises, and acceleration felt sluggish and muffled. Later, I spent over a thousand to replace it with a used part, and finally, the issues stopped.
In our auto repair shop, we frequently encounter vehicles with removed catalytic converters, and we focus on these three key aspects: The exhaust emissions are definitely not up to standard, with the exhaust gas being thick and pungent, making it noticeably irritating to the eyes when standing behind the vehicle. The engine warning light is almost always on, and the engine control unit misjudges the air-fuel ratio, leading to a fuel consumption increase of over 20%. The exhaust sound also changes, with a particularly loud humming resonance at idle and popping sounds when the throttle is aggressively pressed. This can also easily cause poisoning of the oxygen sensor behind the catalytic converter, making repairs more expensive than replacing the original catalytic converter.
Last week I noticed my modified car had sluggish acceleration, and the mechanic said the previous owner removed the catalytic converter. Now the exhaust smells so bad at startup it even drives mosquitoes out of the garage. Rolling down windows in underground parking is pure torture. The yellow engine light on the dashboard never goes off, and fuel consumption jumped from 8.5L to 11L per 100km. The worst part is having to find 'fixers' for annual inspections, and the empty exhaust pipe stands out conspicuously when police check for modifications. Fellow car enthusiasts, don't follow my reckless modifications - only after restoring to factory specs did I understand what true driving comfort means.
