92 Roadmaster suddenly idling rough with black smoke

ERICSCHOLTES

MEMBER
1992 BUICK ROADMASTER
V8
2WD
AUTOMATIC
96,000 MILES

I have a 92 Roadmaster with around 96k miles. Last night we came home and parked what we thought was a happy health car, but this morning when my wife started it up black smoke was coming out of the exhaust and it was idling rough. It sounded like maybe the timing was off or a few of the plugs weren't firing. I don't know much about cars. Please help. Eric. Scholtes@yahoo. Com

Friday, August 5th, 2011 AT 7:41 PM

2 Replies

JDL

MECHANIC
16,098 POSTS

How clong since a tune-up? Sounds like it is flooding? Check for applicable trouble codes. You can check those yourself. Use a jumper wire at the A & B terminals of data link connector, along lower edge of dash. Turn the key just till the dash lites come on, no further, no crank, Then the mil starts flashing, you count the flashes to get the codes. Your looking for two digit codes. The first code will probably be a code 12, one flash, a slight pause then 2 quick flashes. Will probably flash 3 times before moving to next code. Code 12 just means your in diagnostic mode, nothing to worry about. If there are any other codes, let us know.

The picture below is just to show location of A & B terminals.

Image (Click to make bigger)

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Friday, August 5th, 2011 AT 8:16 PM

RASMATAZ

MECHANIC
75,992 POSTS

Probable causes of an engine running rich are as follows:

1. Excessive fuel pressure can be cause by restricted fuel return line
2. Defective Oxygen Sensors.
3. Leaking injectors and fuel pressure regulator.
4. Coolant temperature sensor out of calibration.
5. Restricted air intake system.

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Friday, August 5th, 2011 AT 10:14 PM