My car was running great, i put the KM in and drove it to my Mechanic to have my nitrous system installed, and i never noticed a differnce, but he called me yesterday and asked if i have a problem with the car because it was blowing black smoke out the tail pipes and not running right. I told him that i have never noticed that before. He noticed it before he did any work on it, so its not from anything he did. My car has thrown a check engine light for about a month and a half now because i dont have any cats, i'm pretty sure taht the KN didnt make it run rich, and that its just a O2 or something like that, but we are going to hook it up an dsee what codes its throwing.
thanks for the help

 

the km only affecs the amount of timing the pcm pulls when it needs it, an 02 can cause quite a few problems and possibly pull a code, or maybe you should get a new mechanic..

 

What year is your car?

 

97 z28, M6 if it matters, why do you say i should get a new mechanic?

 

just messin sayin maybe he took it for a joyride after you left and decided to break it and blame it on you..lol

 

LOL this isnt some Gas staion mechanic (i hope i dont offend anyone) its a really trust worthy guy, great reviews at his shop, he deals with performance parts, not general maintenance. What are some other things that could cause it to run rich, i've noticed latley that my gas mileage has SUCKED, like 170 to a tank, thats mostly city driving though not highway. Even when i drive on the highway alot i get MAX like 220. I'm thinking its an O2 sensor, i just really need to know if its anything major cause were planning on putting it on his dyno to test the nitrous. I guess its better then having the car run rich for the nitrous runs on the dyno then lean eh...

 

Your plugs might be goin south

 

Cool cause i had him install some NGK tr6's (for the nitrous) in there so if it was that it was fixed

 

Why didn't your "mechanic" scan it to see what code you were getting? That would be the logical first step.

Year of the car does make a difference in many instances.... that's why most people include a "signature" with year of the car, tranny type and any major mods..... helps people answer your technical questions. Not all LT1's are the same.

 

I know one SES cause if you have the rear O2's intact. Cat efficiency error. You will need these to correct it.
http://www.o2sim.com/6928.html
They're only $25, I got a 2 channel unit from them and it works great on my 99 P'up.

 

Yeah, thats why I was askin what year car he had. If he doesnt have 02 sims that could very well be the code hes throwing since he stated the SES light has been on since he removed his cats.