QuestionI have an 84 deville w/ the 4100 engine. sometimes the service engine light comes on and the car suddenly blows black smoke and runs terrible. this problem is preventing me from driving it due to emission testing. when the light isnt on the car runs fine. any advice? is it a sensor?
thanks a lot
don
AnswerHi Dan,
I can't help you a lot on this issue because I am really straining my memory. 25 years ago and all. The reason the light comes on is because it is out of the loop and that is why it is running bad at that time.
Anything could be a problem however, you have an advantage here.
The service engine light will store a code.
I would tell you how to take a paper clip and put it on the terminals at the obdI port under the dash, to flash the codes, but it is too many years since I did this.
Go down to your local auto parts store. Tell them you need the tool to flash or identify the trouble codes. These tools are pretty cheap now.
Hopefully, the tool you get will identify the codes and what they mean. For example: code 13 would flash on the dash engine light, a long flash and three short flashes. If you looked the code up, you would find that it means a bad O2 sensor.
The tool you buy should identify the codes. If not go to a library and see if you can get a 1984 Cadillac service manual for emmisions.
Sorry I could not be of more help, but hopefully I pointed you in the right direction.
I have an 83' Eldo with the 4.1. I love the car!!!
Good luck!
Rob
