So yesterday I had drove to the exhaust shop for them to do a little work to get my y-pipe to fit. Anyway, when it was done it felt kind of rough, so today I checked the plugs and they were all fouled out - the top part and 2 threads were totally black. So I gave them all a change today thinking maybe it was just from running open headers for the drive yesterday.

I put the new plugs in and went for about an hour drive total. These new plugs have fouled out as well - same condition as before.

I bought the headers used, so all coating should have been burned off long ago. The computer is still using a tune from when I was running mid-length headers. The computer has been reset for atleast 45 minutes as well while I was working. So I am either guessing that the 02 sensors are shot from age or something else (since I believe they are the original snesors with less than 17,000 miles on the car)and it is running rich from the tables in the computer. Or I think it may be picking up false knock, pulling timing and dumping fuel? Any tests I can do to figure out what may be the culprit?

 

Three steps. Hook it up to a scanner. Pull the data logs. Let us read them.

 

I put i new 02s, got a tune, replaced my fuel filter, air filter, oil, every preventative maintainance thing you coudl imagine while installing my LTs and still i run rich. I realized i just noticed i am running rich more with LTs is all. I am 99% positive my FPR is bad, maybe you shoudl check that out.

 

My tune is still from the mid-lengths - but I think it should still be fine. The air filter has been checked within the last 500 miles - as well as the fuel filter has been changed. Oil was changed during the longtube install (as were the first set of plugs that bit the dust) I am thinking that maybe running open headers caused a really rich condition which ruined the O2 sensors? Not really sure, but fetching around for possible ideas. The O2 sensors may have acually been hooked up when running open headers - oops However, I don't have a LT4 knock module yet, so perhaps it is picking up knock and dumping fuel?

I am hopefully going to find someone in the area locally that has a cable and scanner software that will log my car for me so I can post some logs. Can anyone else think of any other possible scenario to cause a really rich condition?

 

Well i have knock tuned out and i still am running rich. Running open headers can cause 02s to run rich from the extra oxygen entering the long tubes. The tune shouldnt matter at all. Remove the 02 sensors and clean them though. I noticed my 1 o2 sensor was really fouled after running open headers. You could be running rich from knock if you are running open headers. When you get a tune, just get the knock tuned out, a tune for your LTs and other mods. You can run a scanner though and see how much knock you are getting. Just datalog it. It shoul also allow you to read A/F ratio and injector pulse and fuel pressure.