Black Smoke, STalling, hard to start....

[ellis_juan]

Hey all, I have a 1983 Buick regal that I just picked up, nice car with only 40,000 original miles. At times the car will run fine, but most of the time it will hesitate while driving, stall when you are coming to a stop, and once turned off, it is very hard to start. I was thinking that its the O2 sensor, but wanted you guy's opinions....thanks in advance.!

[GTP Dad]

Is this car fuel injected? Most of the Buicks prior to 1984 were not fuel injected and therefore do not have an O2 sensor. If it is fuel injected I would definately change the O2 sensor. If you find it has a carb. then check the choke as it may be sticking closed and causing the black smoke and stalling.

[ellis_juan]

Well it is not FI, but it dose have an O2 sensor on the pass. side exhaust manifold.

[Goodwrench358]

Black smoke indicates that your engine is running a rich mixture. Too much fuel is being burned off and will eventually foul spark plugs, O2 sensors, and emissions control equipment. You should check your air filter for debris and damage as a clogged air filter will restrict the flow of oxygen needed for proper combustion.

A fouled O2 sensor will give off a few warning signs (IE: popping sound in the exhaust, slight detonation, "egg fart" exhaust scent, soot, activation of the SES warning light, etc.) indicating that it needs immediate attention. The O2 sensor is part of the emissions control equipment and is responsible for regulating exhaust gas recirculation. Failure of this device will result in increased hydrocarbons and hazardous exhaust emissions.

You may also have an incorrect idle mixture setting on your carburetor. Adjust the idle control screws until the proper idle, RPM, and fuel/air mixture settings are found. Also, be sure to check and clean off carbon deposits from the choke, throttle plates, and other moving pieces.

A good tune up should solve the problem. Then, of course, we have the OTHER "option"...

[GTP Dad]

I stand corrected. Goodwrench358 has outlined the proper corrective actions that you should take to correct your problems.

[ellis_juan]

Thanks for the input guys, I pretty new to these cars, so how exactly would I know if the choke is sticking, and how exactly would I fix it? Thanks again

[BNaylor]

Originally Posted by ellis_juan

Thanks for the input guys, I pretty new to these cars, so how exactly would I know if the choke is sticking, and how exactly would I fix it? Thanks again

What size engine do you have? If 3.8L V6 you should have a two barrel carburetor. If 4.1 V6 you have a four barrel. Regardless, remove air cleaner assembly so you can view the top of the carb. Look for a metal plate (flapper). The two barrel will only have one. On the four barrel the choke will be on the primaries. When the engine is cold this will be in the closed position (flat). Air intake will be mostly blocked. As the engine warms up this flapper will start opening up allowing more air into the carb. When the engine is fully warmed up the flapper will be in the full open position. It is an automatic choke, although crude compared to fuel injection. As the others mentioned you can start by using a spray carb cleaner such as STP.

If the choke appears to be working you have other issues such as an improper float level, sticking float needle valve or possibly a worn out accelerator pump, etc. Rebuild kits are available at the various auto parts stores. Good luck!