Does anybodys car run really rich after header install. I took out my can and am running straight pipes to my muffler. In the tips you can put your finger in and rub it and it is like really black powdery stuff. Someone told me to get a fuel presure regulator?

 

How do you know that it's running rich? Have you put a scanner on it and watched the readings? If you're just going by the smell and black powdery stuff, it's not a clear sign that it's mixing any different than it should. A catalytic converter burns the excess gas and since you don't have one, it's going to smell like it's running rich and you're going to get the black powdery stuff on your tips. Our cars run somewhat on the rich side anyway.

 

Rich is right, you can't really tell if your car is running rich without hooking it up to a scanner. When you remove the cats it will smell pretty bad. Check for exhaust leaks, if you have any before the O2 sensors it can cause the computer to pick up a lean condition and add more fuel resulting in it running rich.

 

I have the same problem as you since I put headers on the car. I know mine is running rich (had it on a scanner). I think it is partly my fault, I have some exhaust leaks that I am really trying to fix (they are before the O2s). Good luck with yours, and my cat is gone too.

Chris

 

Well when I got my inspection my H2 level was at 4400 when you need to be at like 220 to pass

 

I'm not to familiar with smog testing and the readings. But I'm willing to bet the reading was so high because you have no catalytic converter.

 

Ok I'm not trying to be an ***, I'm just fuel injection ignorant i guess, but...
how can ya'll say that you cant tell if its running rich without a scanner?
why cant you check it the same way I always have and just read the plugs like all of us carburated types...
The reason I have to ask is my Z28 isnt throwing any codes, but by reading the plugs and exhaust Id say its running rich too. (new wires/plugs and blah-blah-blah)

 

You can certainly read the plugs....but you need to know what the O2s are seeing to help diagnos the problem. Like someone has allready said....if you have an exhaust leak prior to the O2s the extra air in the exhaust will be seen as a lean condition(false reading if you will) causing the pcm to dump more fuel resulting in an actual rich condition.

 

I have the same problem, headers leak before o2s and running rich, hopefully I'll fix that today!

 

ah that does make more sense when you put it all together gb95z, thnks...
so...if it leaks from the headers you have extra oxygen telling the computer its lean, causing more fuel to be added...this makes sense, but am I thinking to much to get the idea that the larger volume inside the header would cause a false decrease in the reading also? (same amout of fuel/oxygen in a larger area would seem like less present) if this makes any sense...

 

No, the size of the pipe has no affect on the O2 %... because it's a %, not an absolute value. The sensor is comparing the partial pressure of O2 inside the exhaust pipe to the partial pressure of O2 in the air surrounding the O2 sensor. And partial pressure is a function of O2 percent concentration, not related to the density of the gasses in the exhaust pipe.

Headers will generally run rich due to "false lean" conditions... the air educted into the exhaust leaks, mentioned above, is one cause. Misfires are the other cause.... the unburned air has the same affect.... raises the % O2 in the exhaust and the PCM reads it as "lean" and dumps in more fuel. Remember, and O2 sensor can only see "O2", not the fuel content. Burned or arcing wires = misfires.