ooopseyesharted

i have a 1999 civic 4 door.
1.6 non-vtec

About a month ago, I had a check engine light come on.
It was an oxygen sensor code, so i replaced them.

Code was cleared and all was well. Until about 3 weeks ago when the check engine came on again.

I scanned the car and it had 3 cylinder misfires, idle air circuit code, and a cata;yst code

I replaced the coil, distributor, catalytic convertor, idle air valve, and map sensor.

I then read the codes.....all misfires and catalyst were gone.
I reset the ecu.

Then I had an idle air code p1399.
Frustrated, I just said eff it and drove the car.

Well now all the original codes are back.........WTF??!??!?!?!???!
Any ideas????
I read need help before i burn this car to the ground.

90Rexx

diag before throwing parts at the car.... your engine is misfiring, which is setting your catalytic converter and oxygen sensor codes. fix your misfire then clear all codes, if oxygen sensor and cat code come back then you would need to adress those. codes are numbered for a reason... fix them in order! you probobly have like p0301 p0302 and p0303 and maybe a p0300 right? those are the lowest numbers so fix them first. cap rotor plugs wires to start. its afecting multiple cylinders so concentrate on a single component that can affect multiple cylidners. possible dizzy as well. PM me if you need any more help.

ooopseyesharted

ok.... i will get the plugs, wires, cap, and rotor.
i didnt know that you had to repair them in order.

I replaced the distributor and coil already.....no changes

95civic 4door lx

.....yea bro u always start with the smallest thing first wen diagnosing....fuses.visual inspect.ask your self is it electrical gas. air, braking related. then you tackle that... saves money... like in your case I already feel u wasted uncessary money......any mechannic will tell you always fuses first.not just because it says on ur scanner cylinder misfire does that mean u have to change a piston.... old sprk plug wires ,plugs , dist cap could set off a code......I scanner is just as usefull as the person using it. a scanner help give u an IDEA where to look.never the answer

REDesignIT

is the motor stock or modified ? any bolt on's headers, intake etc, aftermarket plug wires ? when and what type of spark plugs did you use on the last service ? what mileage is on the car ?

Could be a whole host of things, some of which not even directly electrical related.

Carbon build up, low flow injectors, bad headers design back firing off cycle into a "cold" cylinder, bad TPS, carbon build up in throttle body throwing the airflow reading off etc.

Down to a partially detached spark plug head wire boot giving an intermit high resistance reading back to the ecu to a burn off tip on the spark plug or carbon build up on the tip.

Car running lean lately ? poor gas mileage, performance a little off ?

Did you change the fuel filter recently ?

Redbone

and also poss bad ECU

sauceja

I would start with spark plugs instead of buying everything. Change them and clear codes. Then if you want get wires and some other things.

I will bet though that your spark plug gap is around .050 or higher causing weak spark. If you bent the prongs back down a little and regapped them and tried starting it again your codes would stay away but for 2.00 a plug its easier to change them.

And PLEASE buy NGK's.

Most of that is called a tune-up and if you do a tune-up from time to time then when you get a cell you don't start wasting money foolishly.

At least you are taking an interest in your car though and sounds like parts you are buying is really not gonna be a waste cuz you will look back and say "well at least those parts are taken care of".

ooopseyesharted

Ok. Here are the updates.
I was given great info by you guys and should of come here first. I pulled the car into my garage. i decided what the hell and pulled the #4 plug wire. It made NO difference in the way the car ran. i tried the other 3 plugs and they all made the car run terribly.

I closed the garage door and pulled the #4 plug again. I was arcing everywhere. All this time it was a friggin spark plug wire!!!!!!!!!!!!!!!!!!!!!

I replaced the plug wires and also installed NGK v-power plugs.
The car runs great now, although the check enigne light came back on after about 30 minutes of driving today....LOL
I swear to god this car hates me.

ooopseyesharted

I had that code scanned at the almighty advance auto parts.....LOL

P0420 catalyst below threshold (bank 1)

I removed my battery cables earlier in the day and the light shut off. It came back about 30 mins later. The guy at advance said that removing the cables would not permanently remove the code. Is that true? I erased the code at advance and it didnt come back on my way home.......so i guess we will see.

98civdx

haha the car doesnt hate you its just being a honda
they are bitchy
evrytime i fix something on mine something else blows
glad you got her runin right!

jimmy o.

that code p0420 is a bs code my 96 probe threw this code every 2 months i just kept deleting it with my scanner as my gas mileage was great and my car ran perfectly

Townson

resetting the code only temporarily keeps the cel away. lol. i know from experience.

sauceja

If you remove the fuse for the ecu which doesn't neccessarily mean the ecu fuse (scratches head) but should delete the code for good. If it comes back somethings going on.

And yes Honda's are like a mix of pregnant women on the rag ( I know not possible but if it could be then she would be like a honda ) I just feed mine chocolate ice cream with bananas on saltine crackers and she stays pretty happy haha.

REDesignIT

yupe he is right, you have to disconnect the battery and remove the ecu reset fuse. Wait 10 minutes, put fuse back in reconnect battery and start car let it idle without touching the gas. Then after 5 minutes you can do what you want.

And yeah Honda's are crazy once you get rid of something you get down to other lower level issues that through codes.

I would guess you might have too hot a plug for what the motor is really doing - typically if you get the wrong V power NGK and personally they sound cool as hell, but reality is they suck so go back to the OEM spec plug. Or your O2 sensor is a little out of wack due to a high flow exhaust pulling in lots more exhaust without the positive back pressue the cat actually runs cooler which in turn does not sponge the proper amount of "bad" emissions. So your outgoing air is more dirty.

The back pressure in a stock honda is needed to heat the cat up to the proper temperature to "burn" off the bad stuff going out the exhaust. Less back pressure less heat, thus low temp code coming off the O2 sensor throwing the code.

Does not affect driving or performance one bit, but will be some issue for smog (if your state has smog checks). I believe there is a resistor mod you can do to the stock O2 wiring to bump the reading back to the ecu to prevent the low temp code from being tripped.

B serious

iTrader: (1)

What type of cat did you replace it with? A lot of aftermarket cats are garbage and won't meet OBD2 specs.

The cat could also have been damaged due to the misfiring.

If your cat is aftermarket (cheap), it most likely just doesn't meet the ECU's parameters for a clean running car. Remember that this is a OBD2 LEV. Meaning that the ECU will be strict as far as emissions go. The new CAT's efficiency threshold may not be good enough for the ECU.

REDesignIT

good catch B, your right, I missed that about him replacing the cat, if it was some cheaper muffler store cat, vs OEM it could be just that. The cat is not up to spec and does not "heat" enough to register for the O2 sensor for "clean". Any event pretty sure the O2 mod will still work.

B serious

iTrader: (1)

I'm always right.

Former User

As mentioned, the engine misfiring likely killed the new cat; however, before you replace this expensive part, first look for a possible exhaust leak somewhere between the primary and secondary O2 sensors.

ooopseyesharted

this is an old posting but, it turned out that the #4 cylinder was misfiring and making the ecu freak out.
The plug wires I bought were defective and #4 was arcing all over the place.
The only reason I found out was because I decided one day to remove plug wires one by one to see if the misfire got worse or didnt change.

The first wire I pulled was #4. The car ran exactly the same with the wire unplugged. I turned off all the garage lights and it was arcing like crazy!

Friggin autozone wires!!!! Bosch wires!!!!! Screw that. I replaced them with OEM wires....problem solved.