2001 Buick Regal cat. Converter causing poor performance.

Tiny
SFSCCC33
  • MEMBER
  • 2001 BUICK REGAL
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 99,000 MILES
My car would accelerate slowly, hange around 2000-3000 rpms, but would drive fine once at speed. I recently got the car diagnosis at a dealership and they said my cat. Converter was clogged. I bought a new one and had it put on. The car ran great for about 4 days. Then I started to notice some of the old symptoms coming back that the cat. Converter might be clogged again or starting to clog up. The car will not exceed 3000 rpms but still accelerates fine. It is burning gasoline faster and the engine temperature is higher then normal. The car just went through a rough winter so I do not know if the winter affected my car somehow. What is causing my cat. Converter to clog? Did the winter disrupt anything?
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Tuesday, March 17th, 2009 AT 10:19 PM

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Tiny
RASMATAZ
  • MEMBER
Causes Of Converter Failures

Fouling, clogging, melt-down and breakage of the ceramic substrate inside a converter are common conditions that can cause problems. Plugging is usually the end result of a melt-down, which occurs because the converter gets too hot. This happens because the engine is dumping unburned fuel into the exhaust. The excess fuel lights off inside the converter and sends temperatures soaring. If it gets hot enough, the ceramic substrate that carries the catalyst melts.

The unburned fuel may be getting into the exhaust because of a bad spark plug or valve, but an overly rich air/fuel mixture is another possibility. In older carbureted engines, a heavy or misadjusted carburetor float may be the underlying cause. But on newer engines with "feedback" carburetion or electronic fuel injection, the engine may not be going into "closed loop" (the normal mode where the computer regulates the air/fuel mixture to minimize emissions).

A bad oxygen sensor or coolant sensor may be giving the computer bogus information. A sluggish or dead O2 sensor will make the computer think the exhaust is running lean, so the computer will try to compensate by making the fuel mixture rich. A coolant sensor that always indicates a cold engine will also keep the system in open loop, which means a steady diet of excess fuel. But it might not be the sensor's fault. A thermostat that's stuck open or is too cold for the application can prevent the engine from reaching its normal operating temperature. So if your converter has failed and needs to be replaced, the engine should be diagnosed for any underlying problems before the new converter is installed.

Another cause of converter clogging and contamination is excessive oil consumption. Worn valve guides or seals can allow oil to be sucked into the engine's combustion chambers. The same goes for worn or damaged rings or cylinders. Oil can form a great deal of carbon, and metals present in the oil can contaminate the catalyst. A compression check or leak-down test will tell you if the rings are leaking, while a fluttering vacuum gauge needle will help you identify worn valve guides
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Tuesday, March 17th, 2009 AT 10:27 PM
Tiny
ANDYMAN1279
  • MEMBER
Seems to me that once the vehicles hit right at the 100k mark that those symptoms appear, is there anyone out there that has a sure fix? Is it just age and eventually components will just start failing one by one, leading to replacing parts every other week?

Sounds like a common problem, and there has to be a common solution, rather than starting from the front and replacing all the fuel related parts till you reach the rear.

Just a concerned forum reader who wants to get to the bottom of the buick regal troubles.
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Wednesday, April 22nd, 2009 AT 5:48 PM

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