black smoke

[tnt]

hope someone can help me 84 GN when i get into the gas the car makes black smoke out the pipe i know that it is rich but but what makes it do that?

 

[JayLashua]

well, my limited experience, is rich = good. try giving it more boost to increase the air/fuel mixture and see if it takes care of it

last thing you want is to not be running rich enough when your boost is maxed out

or, maybe its just a wacky sensor thats not working correctly=/
hth

 

[dave84gn]

Well, the best thing to do is get your car on a scantool and check what your sensors are telling you. Your O2 sensor controls lean/rich, and your fuel pressure also contributes to this. If you have an adjustable fuel pressure regulator, you could turn down the pressure, but more likely it sounds like something is a little out of wack. If your O2 sensor is shot it constantly reads lean and your computer richens up the mixture, which could be your problem.

Again, a scantool would tell you right away what your problem is.

One thing you *could* try is unplugging your ECM (orange wire under the hood) and then plugging it back in ("reset it"). So if it is your O2 sensor then your car shouldn't run rich for the first little while after resetting the ECM, but then it'll start pretty soon after that. Just a thought.

Let us know how it goes.

Dave

 

[tnt]

I ck out the o2 it is fine i am pretty new to this what is a scan tool where can i find one how much do they cost and what do they do i hear every one calling about them.

 

[Buick From Hell]

Rich is better than lean, but TOO rich can cause detonation...

Also, your black smoke may be BECAUSE of detonation, they'll blow smoke while they're knocking!

How much smoke we talking about? A lot, some, or just a little?

 

[tnt]

just a little only when i am in the gas.

 

[1984grandnat]

Scantool can be made at home with a paper clip or small piece of wire.
Short pins A and B (Upper right pin and the one to the left of it) on your ALDL connector (just above center console, driver's side, below radio housing). Turn on the ignition. The SES light will blink once, then a long pause. The light will blink once again pause blink twice. This is called CODE 12. It will do this 3 times in succession (one blink, pause, two blinks). After the third time, it will blink a number of times to indicate trouble codes that are stored in the computer. It will repeat each code 3 times (so pay attention and write them down!). When it shows code 12 again, that means there are no more codes in the memory. After you pull the codes, unplug the orange wire at the battery to reset the ECM.
If you need to know what the codes mean, most of us can probably tell you (once you get the numbers).

 

[Buick From Hell]

1984grandnat, the "scantool" Dave is referring to is one of several aftermarket tools that reads your ECM while driving! Many factors are involved, but normally these are able to display voltages/values of some or all the sensors, and the amount in degrees the ECM is retarding ignition due to knock (among other things!) A good scantool is a must to fine-tune these cars!

What YOU are referring to is using the SES light to obtain trouble codes stored in the ECM, which is also very useful to know! And since you brought up the "paper-clip" trick, many people don't know about the "field service mode" using the same paper-clip trick!

Basically, the SES light is used to "read" 02 sensor voltage! (approximately, anyway) To do this, you simply START the engine with the paper clip "installed"! The SES light will react these ways:

1) Flashes 2.5 times per second--this indicates the ECM is in OPEN loop;

2) Flashes ONCE per second--this indicates the ECM is in CLOSED loop, and the 02 voltage is between .35 and .55 volts

3) it will stay OFF most of the time--this indicates the 02 is less than .35 volts, or LEAN

4) it will stay ON most of the time--this indicates the 02 is more than .55 volts, or RICH

Normal conditions are: light staying ON a long time under acceleration, light staying OFF a long time during deceleration, light BLINKING most of the time while cruising, and light staying ON a long time while idling.

Maybe this will be of help to someone!

 

[1984grandnat]

Thank you for clarifying my information.

I myself was not aware of the "field service mode". This is very good information that could be useful in a number of situations. Make it a little easier to tune AF ratio, and adjust fuel pressures, maybe?

 

[Buick From Hell]

Well, the field service mode could help find a bad 02 sensor, or maybe help narrow down other problems, but the "info" is pretty broad compared to a scantool, which will give you real-time readouts right down to millivolts! But if you have a driveability problem and don't HAVE a scantool (I don't!), it can help!

 

[tnt]

thanks guys just got a scanner from autozone going to try it tonite tell you what i find.

 

[tnt]

just used the scanner came up code 12 # im at a lost.

 

[turbowrenchhead]

Find someone who had a snap-on scan tool. See if they can look at the datastream. You will be able to see if the O2 is switching properly. If the temp sender is correct and so on. This will tell you a great deal of information. I personaly like the lap-top with turbolink program. I use my friends all the time. It has saved me many times.