djshaggy

I have done a search, but I need some more help...

I have some headers and I was throwing a CEL until I put in a high flow cat and relocated the second O2 sensor behind the cat...but after driving through some engine cycles I am getting the CEL again, and I was wondering if this is because the lengthening of the wires put the 2nd O2 sensor too far away from the 1st and changes the reading sent to the ECU and if so, would relocating the 1st O2 sensor to the downpipe fix the problem because both O2 sensors will be as far away from eachother as they were stock?

When I lengthened the wires, I used a high quality 14ga wire, so I don't think the longer distance has much resistance because of the bigger wire... Please let me know what you think.

LarryMcFly

No, the longer wire is not the cause of your problem.

The best way to know is to have your ecu scanned, then you will know for sure.

CyberShark

Mine does the same thing. It's doing that probably cause you have a high flow cat now.

cdogtibby1

i've got the same problem. i've had the code run... came back "catalyst above threshold" or somethin like that. it sucks and i cant figure out how to fix it... o well.

djshaggy

Thanx for the responses, I tried running the code before but autozone kept having trouble with their machine, I am going to try another one though

I just can't stand the yellow light of death

hamhead

If you can't stand it, disconnect it. lol.gif Your probably throwing the code because you only have one cat, and its a high-flow so its not filtering as much as a normal one. So it knows its not cleaning as much as it should.

CyberShark

I've had that light on for over two years now. If you leave it on, you'll get used to it. I don't think it hurts anything.

hamhead

During normal driving with a CEL, the ECU will dump a poop load of fuel just to be safe in limp mode. If you floor it, you go into closed loop, where it just bases it off o2 sensors and such. So I would imagine running with a CEL would be bad for your gas mileage, and I would imagine the carbon buildup and gunk in your exhaust covering your sensors would suck.

Think of it like a heart. During 'normal' operation (healthy), the heart arteries are unobstructed. When you add too much cholesterol (fuel) it gunks up the arteries and restricts flow. That adds more strain on the heart (engine), and reduces blood flow (intake/exhaust). That restricts horsepower.

I guarantee some of you that have low dynos on RDs is because you don't keep the engine itself clean. Whether it be letting too much oil bypass and letting it sit in the Intake Manifold, or letting carbon buildup to the extent that it sits in the combustion chamber and blocks your exhaust ports. I guarantee I'm sitting at 132 whp with just I/E as I'm running my car 15.5 with I/E in the quarter (68 degrees, a little humid, about 300 above sea level), then hopped in a friend's Celica/Civic/etc. thats sitting right around 140WHP and run 15.3-15.5 consistently on the same day.

CyberShark

Na, it's not that bad..I still get 33miles per gallon on the highway. I just had my exhaust removed too and there was no excessive carbon in there either.

hamhead

Its not so much the crap in the exhaust as it is the crap in the head and on the ports from the exhaust manifold. When I ripped apart the Tibby when I got it, with 8k miles on it, there was still a good layer of oil on the IM from the oil blowby. I haven't ripped into the actual combustion chamber on the Tibby yet, but I would imagine its getting a tad gunky.

This becomes more of a problem when you turbocharge a car. The oil blowby degrades gas octane and increases detonation. The oil won't be much of a factor on a n/a setup except being there and being icky. Plus theres less blowby on a n/a setup anyway.

Leaving the CEL on in a 2001 and previous Tibby isn't as harmful as the newer cars. Tons of GK owners have ruined o2 sensors simply because all the ecu's dumped gas gets on the sensor and fouls it. Even n/a.