Can anyone explain why headers would make your car run rich? Could it have something to do with no cat installed maybe? Or maybe my A/F gauge is jacked up? HELP!

 

Everyone says thay Hyundais run WAY rich so you'll probably need to trim the fuel back. Having no cat could also be your problem. Your computer probably doesn't know how much fuel to add and is just dumping alot in.

 

hey dude,
did u remeber that there's and upstream o2 sensor that's supposed to be screwed into a bung in the header? i don't think any of the aftermarket headers come with them already pre-drilled (why, i dunno.. cus australia and places don't use em? someone should fix that crap for us US people) but anyway, yea ulll run rich AND have a cel come on. i think mines burnt out right now, cel on, and actiing no different really..same way as it did when the downstream one burnt out. but that'd make u run rich/lean, but usually rich.

 

Interestingly enough, no CEL even though no CAT. Up stream, down stream, I dunno which way is which but I do have 2 o2 sensors hooked up. My headers came with an o2 sensor bolt welded on. I've been under the impression (from researching the net) that the second o2 sensor just monitors for CAT failures. And the first o2 sensor is what reads the mixtures...

Rather than trimming back the fuel, how about adding more air? Anybody know if a throttle body from a Tib will fit a 1.6 Accent? And if it does bolt up, anybody know the stock diameter of the Tib TB and how much larger you can SAFELY bore it out to?

Thanks!

 

The item's in my signature currently are making me run on the lean side...meaning I have the Autometer Phantom A/F gauge, and at warm engine idle at 855RPM ( ) I run two clicks away from entering the LEAN zone. And with A/C on while driving on x-pressway..im in lean....not I know this cant be "good"...but im getting dyno tunded this coming week..hopefully. So it should be fixed then.

 

Where did you get your Rich/Lean meter?

 

It was the cheapest one I could find on Summit Racing. Maybe that's the problem all in itself?

 

There are many brands of A/F meters. Also, simply changing the location of the o2 sensor can alter it's readings.

The important thing to remember, is that o2 sensors need to be warm in order to work. Let the car warm up to normal coolant temp before you start worring about A/F gauge readings. And then...if the A/F gauge is pegged rich 24x7, then something is wrong with the way that the A/F gauge is hooked up...or with the o2 sensor itself.

 

It only runs rich at WOT. The first yellow light is constantly lit at WOT and it sometimes hits the second yellow rich light in 3rd and 4th gear at WOT.

 

Your computer is probably designed to work with readings that are "post cat" readings. When the ECU finds something not usual (due to removal of cat, not proper relocation of sensors, sensor failure, or others like these) it enters the "auxiliary mode" and it sends a lot of fuel in the chambers, asuming it's better to have too much, than to have too many.
First, I would check as Random suggest if your A/F meter is properly installed, and then if the sensors are working OK. If you haven´t changed anything else in your car, the ECU shouldn't be getting rare readings, but it depends on the way you have configured your engine.