ok i just put on MR headers and now mi check engine light is on.. i already reset it once but it came on again.. it said cyclinder 2 4 miss fire and some other things.. but is it the header or the sensors??any ideas??please help

 

Did your header have a cat on it? With out the cat the o2 sensors will set that light off. I have heard that if you dont run a cat on some civics it will set the check engine light on and you could possibly have other thinks go wrong but once again thats all hear say.

 

It's the Oxygen sensors. Do you have a catalytic converter anymore? If not, you'll need something to dissipate the fuel in the exhaust, before the O2 sensor picks up it's readings.

 

they took it off and what do u think will happen?? is mi car guna break down? will i still be able to drive it????

 

It won't run right at all. You'll be running extremely rich.

 

HUH????dude im tripping *****...... is that a good thing or bad?????

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bEnR’s civic04 &raquo;</TD></TR><TR><TD CLASS="quote">HUH????dude im tripping *****...... is that a good thing or bad????? </TD></TR></TABLE>

That's bad. Running rich, means you're burning a ton of excess fuel.

 

and building carbon up in your exhaust and valves and combustion chambers.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by toyomatt84 &raquo;</TD></TR><TR><TD CLASS="quote">It won't run right at all. You'll be running extremely rich.</TD></TR></TABLE>

i've understood that, when running exhaust sans catalitc converter the secondary reads too much fuel so the ecu adjusts and leans out, so in truth without a cat, you running lean.

 

oh god your spelling is killing me right now. you have a few options, depending on what "they" did. If they just replaced your cat with a test pipe then you might still be able to attach the o2 sensor with an o2 sim plug adapter.. that would give your sensor the right reading and your check engine light will go away...

or you can put back on your factory cat..

or if they replaced your cat with just a pipe, they'll have to drill a hole, put your sensor back in with the bung and it should read right again

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by OVNI_CIVIC &raquo;</TD></TR><TR><TD CLASS="quote">

i've understood that, when running exhaust sans catalitc converter the secondary reads too much fuel so the ecu adjusts and leans out, so in truth without a cat, you running lean.</TD></TR></TABLE>

Incorrect. When your ECU is seeing an Oxygen Sensor error, it goes into "Open Fuel Loop" as a precautionary state. Basically, it dumps fuel into your engine, to keep you from stalling.

 

So what should I do..should I just get sum new headers? But the shop that installed it told me that they we're guna put in a extension on da sensor and pull the batt off. And it should take away the light..and so will mi car blow up??

 

You need to calm down and do some research. This has been answered before in extreme detail. Get some spark plug defouler's to fool the O2 sensor to think it's reading properly, and clear your ECU.

PS. It's "header" by the way. You only have one.

 

that is only true if the o2 sensor is at fault otherwise the o2 sensor will see rich and tell the ecu to lean it out burning holes in pistons if not corrected

 

go here:
https://honda-tech.com/zero...31152

then:
http://www.civicforums.com/for....html

then:



$3.97 at Advance Auto Parts

just need to modify the opening on one of them to accomidate the sensor tip




Modified by OVNI_CIVIC at 10:42 AM 3/23/2008

 

OMNI sells the o2 sim adapters but they cost $40 they are made of tatanium though you should check them out you don't need to modify anything.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by toyomatt84 &raquo;</TD></TR><TR><TD CLASS="quote">

Incorrect. When your ECU is seeing an Oxygen Sensor error, it goes into "Open Fuel Loop" as a precautionary state. Basically, it dumps fuel into your engine, to keep you from stalling.</TD></TR></TABLE>

it's open loop, not open fuel loop. and it goes into open loop to keep the AFR rich to keep from damaging the engine from a lean condition, not to keep it from stalling.

OP- usually removing the cat will generate a P0420 'catalyst low efficieny' code. you said you were getting misfire codes, which is definately something to worry about. have whoever installed your header fix whatever needs to be fixed with the o2 sensors, whether it be a cable extension or o2 simulator that needs to be installed. Clear the codes and try again. if you still have misfire problems, you will need to address them based on the codes generated by obd2. I ran my car without a cat at 14k miles and have been driving it since with no CEL and no driveability or fuel trim problems. It just comes down to proper installation.

 

is your car an LX? i bought the Megan Racing Header for an LX. i dont want to run into the same problem.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by skipbarber &raquo;</TD></TR><TR><TD CLASS="quote">

it's open loop, not open fuel loop. and it goes into open loop to keep the AFR rich to keep from damaging the engine from a lean condition, not to keep it from stalling.

OP- usually removing the cat will generate a P0420 'catalyst low efficieny' code. you said you were getting misfire codes, which is definately something to worry about. have whoever installed your header fix whatever needs to be fixed with the o2 sensors, whether it be a cable extension or o2 simulator that needs to be installed. Clear the codes and try again. if you still have misfire problems, you will need to address them based on the codes generated by obd2. I ran my car without a cat at 14k miles and have been driving it since with no CEL and no driveability or fuel trim problems. It just comes down to proper installation.</TD></TR></TABLE>

i dont understand what either of you are saying. if your ecu is not seeing at all or getting bad readings from a sensor , it will run parameters which are preset to be "safe" until the problem is corrected , but this isnt true for all problems. sounds like both of you are a little confused about what open and closed loop is. when your putting around not on the throttle much(say 80 kpa MAP pressure and under) , your ecu runs in closed loop , always searching to attain a 14.7:1 AF(stoic). when you are on the throttle , it switches to open loop , and reads directly from the fuel map. what determines whether the ecu is in open or closed loop , is MAP readings.

 

yes its a LX and i tried to reset the light theres no more miss fire..just the bottom sensor thingie. but iuno ima take it back to the shop 2morow..will i die if it stays on??will it just break down on me??..

 

drive it easy till its fixed , youl be fine

 

Heyyy if it happens to blow up d17a1 engines are really cheap on ebay or off of craigslist or you can drop in a K series then. Good luck, let us know how you make out, and do some research before you do anything else next time, thats why we are here.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by blackKready &raquo;</TD></TR><TR><TD CLASS="quote">

i dont understand what either of you are saying. if your ecu is not seeing at all or getting bad readings from a sensor , it will run parameters which are preset to be "safe" until the problem is corrected , but this isnt true for all problems. sounds like both of you are a little confused about what open and closed loop is. when your putting around not on the throttle much(say 80 kpa MAP pressure and under) , your ecu runs in closed loop , always searching to attain a 14.7:1 AF(stoic). when you are on the throttle , it switches to open loop , and reads directly from the fuel map. what determines whether the ecu is in open or closed loop , is MAP readings. </TD></TR></TABLE>

You may want to read some of the information that Hondata puts into their into their tuning documents for their K-Pro units. I know exactly what I'm talking about.

 

blackKready- anytime the check engine light is present, if it is a type A failure, the car will default to open loop with fuel enrichment to prevent potential engine damage from a lean situation. this is because it's safer to run a motor in an excessively rich condition than a lean one. ive studied obd2 for over a year, im not confused about what open or closed loop is. 14.7:1 is stoich, however, during closed loop the ecu is cycling between rich and lean, the primary o2 sensor sees the fluctuation in AFR, the secondary o2 is looking to nearly flatline after the cat, this is how it ensures operation of the converter. If one or both of the o2 sensors is missing, or skewed (see: comprehensive component monitor) the ecu will generate a MIL and default the car to open loop status during all operating conditions to protect the motor. this goes for just about any primary sensor. the d17 run a speed density system. it uses a MAP, CKP, TPS and primary o2 sensor to calculate load and AFR. while cold the ECT is also a primary sensor. (as any obd2 car will always start in open loop for cold enrichment then go to closed loop as it approaches normal operating temp) IAT, secondary HO2S, CMP, etc. just help fine tune the fuel trims both short and long term for engine operation. If all of the major sensors are functioning properly, the ecu will cycle between open and closed loop based off of 2 things; cold start and manifold pressure. If not, the car will run in open loop at all times until the MIL indicated is corrected.


Modified by skipbarber at 7:02 PM 3/23/2008

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bEnR’s civic04 &raquo;</TD></TR><TR><TD CLASS="quote">yes its a LX and i tried to reset the light theres no more miss fire..just the bottom sensor thingie. but iuno ima take it back to the shop 2morow..will i die if it stays on??will it just break down on me??.. </TD></TR></TABLE>

would you please just chill out and read what we're all telling you on here? jeez man..