hey, got a small problem.
I've tried searching for similar topics, but to no avail.
all was fine until my new headers got installed, and now my engine light stays on (I've heard of using an O2 simulator, but cant find one) as well as I only get 400kms to a full tank (250 miles). so my fuel economy has dropped WAY down, plus there's the engine light. and it only all started when the headers went in.
Car: 2005 honda civic DX
Headers: megan racing lx/dx 1-piece stainless steel headers (cat delete headers)
cat-back: magnaflow
Cat: none
Intake: AEM V2

plus also have the tru-power underdrive pulleys from AEM

any help or solutions would be phenominally appreciated

 

did you reset the ECU? did you screw in all the oxygen sensors correctly? Did you have to extend/spliec any wires? Those are all things to consider. www.o2simulator.com or eBay have the simulators you want. If you ctu all 4 wires you'll need the heater wire simulatoir too, but its like 10 extra bucks. I hvae the ones off ebay (both the o2 and heater wire simulators) and tehy are working jsut fine. Spent like a total of $35.

 

without the sim, youll never get it to run right with no cat. either take the header off, or run a sim. i'd run stock header before i used a cat-delete megan.

 

The reason you got a cel is because you don't have a cat anymore. I just didn't put the second o2 sensor in the exhaust pipe, it is just hanging. No cel but I don't know if that will work for your 05 but it did for mine.

 

mobsta, wouldn't letting it hang out affect your mileage negatively like it does for turgodd, since the o2 sensor is not reading the amount of leftover oxygen in the exhaust?!

it would think you have a lot of leftover oxygen and pump more fuel? maybe? i dunno!

 

have a CEL at all makes your HP drop and gas mileage go to shir. If youre in the common header = cat delete situation, a simulator is the only way to go. You can get the code read to be sure, but if your 2nd o2 sensor is hanging, thats a big problem.

 

Primary sensor is used by the ecu for a/f tuning. Secondary is just there to make sure the cat is working. So no that isn't a problem as far as I can tell.

What confuses the hell out of me is that I know I don't have a cat but even if I do put the secondary into the exhaust I still don't get a CEL...[>:] Because of this the real reason I don't keep it connected is because I keep my wide band gauge sensor plugged into that secondary o2 bung. (I know the cel light still works, it comes on and shuts off like it is supposed to when you turn the key on. I have also connected my code reader to the obd port and it shows no cel's)