Black smoke when heavy throttle..

[CarbonBlack240]

So I have been told while people are following me that when I mash into the gas pedal I have dark brown smoke rush out of the exaust... I have had this problem on my work truck before but that was because the injectors were bad. This car has carbs so Im stumped... I can here that the rocker arms are out of line but the car still runs great so it must not be that bad, but can that be the cause of the dark smoke?? It only happens when I mash on the gas.. Please help!!

[SteveJ]

Read your spark plugs. Look for carbon fouling. That 4 barrel carb might be dumping too much fuel in.

[torker]

Yea check your plugs first and you might check your distributor advance and make sure it is moving freely. What carb are you running?

[CarbonBlack240]

I just replaced the spark plugs about 2 weeks ago. Could I have done something wrong when putting the new ones in? And I have a Holley 4-barrel carb that has recently been tuned.. Im thinking maybe the guy who tuned it might not have done it right?? I will post pics of my raceing SU carbs that I have and maybe ya'll could tell me if I need any additional parts because I'm not sure if I have everything.

[CarbonBlack240]

Is this everything I need to get rid of the 4-barrel and put these in??

[SteveJ]

I just replaced the spark plugs about 2 weeks ago. Could I have done something wrong when putting the new ones in? And I have a Holley 4-barrel carb that has recently been tuned.. Im thinking maybe the guy who tuned it might not have done it right?? I will post pics of my raceing SU carbs that I have and maybe ya'll could tell me if I need any additional parts because I'm not sure if I have everything.

Did the valve train noise start up after you replaced the plugs? If you didn't get a spark plug wire on securely, you could end up with a dead cylinder. The miss would be noticable.

The picture you posted was very small. I couldn't see enough detail.

[conedodger]

I would suspect that there is no way to properly tune a 4 barrel. You are probably rich when the progressive barrels kick in. Very inefficient. Go stock...

[CarbonBlack240]

I will try to blow up that pic on my computer so you can see it better. And All the wires are on securely. I noticed the noise after I crossed the spark plug wires and tried cranking the car. It took me 3 times to get the wires back in the right order. Then I noticed the ticking noise coming from the head of the engine...

[Gary in NJ]

A brown cloud on acceleration could very well be a rich condition. A plug reading is your first diagnostic tool in this regard. If the plugs were recently changed, they are perfect for a plug reading. If they are wet or wet-n-black, your mixture is too rich. As you remove the plugs, keep them in order so you can determine which cylinder(s) are running rich and which are lean (yes, you can have both, especially with a 4bbl carb on an L6 engine).

[Bruce Palmer]

Stuff an old sweat sock in the secondaries on that 4 barrel. There is a reason NISSAN went with the Hitachis when they designed the Z.

[tlorber]

Changing your screen name might help too!

[torker]

Changing your screen name might help too!

Haha I was going to say this earlier:) Really though a 4 barrel on a straight six can't be good for mixture distribution. You would have to run it rich to keep the end cylinders from going too lean I would think.