I just bought a 1997 Civic HX Coupe with CVT. My check-engine light has been on for a while with the code P0135 being thrown. It's a "O2 Sensor Heater Circuit Malfunction" code. I finally went to change the o2 sensor and when i removed the heatshield I saw that the header is cracked where the sensor goes.

I got a few questions I am hoping someone can help me out with.

1)_Is the code more likely to be from the cracked header or the o2 sensor?

2)_And does the HX use the same headers as other civics do?

Any help would be greatly appreciated.

 

more than likely its just getting false readings cuz of the crack. now if other civics use the same header, i have no idea but i think they do....besides the lx, the cat is on the exhaust manifold

 

the cat is on the manifold on the hx also, so no all civics do not have the same header.. lx and hx are different.


my guess would be you are getting a messed up reading due to the crack.

 

no lx has an inline cat under the car dx have the cat in the exhaust manifold

 

So now that I know I need new headers anyways, where a good place to get some decent headers for not too much ca$h? I mainly just want my car to run well, I wouldn't get performance headers unless the price/quality is about the same as some cheap OEM quality headers.

Thanks again for the help guys.

 

if the cat is on the manifold then it will be illegal to get a header and not the rest of the exhaust syestem, you would need a catback for like an ex and then buy another cat to bolt up between the b pipe and header

 

Your in Cali, so you're kinda screwed. ALL aftermarket headers are illegal for an HX in CA. You can't move the location of your stock cat. The closest thing I've seen is this from Catco: http://store.summitracing.com/...42630

I'm not sure if it's CARB legal, but it looks stock, and I think your stock heat shields would fit. So you could probably slip by.

Good luck, I have an HX too. As soon as I found out the exhaust manifolds crack, I got a cheap header, and keep the stocker stored for smog.

 

Well, what I ended up doing was installing the o2 sensor and just using some J-B weld on the crack. Right now my civic is sitting in the garage while the jb weld dries till tomorrow morning.

Everything should be fine i think/hope. My CEL went off as soon as I changed the o2 sensor and I just put the JB weld on as a precaution. I think I might get lucky and get off easy but if not Ill be sure to update this post if I'm not so lucky.

 

I guess I am not so lucky.

The J-B Weld just burned right off, the header just gets too hot when driving.

Plan B: I went out and bought some heat wrap. Now I'm just hoping I can wrap a bunch of heat wrap around the area that has the crack.

The car is running pretty good right now even with the crack on the header but I plan to do a 1000-mile round-trip drive soon and don't want any problems. I hope the heat wrap on the header will be good enough.

 

http://www.hondaautomotiveparts.com

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by tuck’d98 &raquo;</TD></TR><TR><TD CLASS="quote">no lx has an inline cat under the car dx have the cat in the exhaust manifold </TD></TR></TABLE>

does anybody know what they are talking about????? 92-95 vx/cx have the cat off the manifold si/lx/ex/dx have the cat under the car.

96-00 hx/dx/lx have the cat off the manifold si/ex have the cat under the car

and if you dont believe me.. go look any misprint info somone corect me

 

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

does anybody know what they are talking about????? 92-95 vx/cx have the cat off the manifold si/lx/ex/dx have the cat under the car.

96-00 hx/dx/lx have the cat off the manifold si/ex have the cat under the car

and if you dont believe me.. go look any misprint info somone corect me</TD></TR></TABLE>
Correct

 

Don't use JB Weld...you now know why. There's a special compound (that looks a lot like JB Weld) that is specifically for filling in exhaust manifolds. I spent 6 hours grooving out my 4ag manifold with a dremel (the crack practically circumscribed the collector) but the compound held up pretty well. Hope your crack isn't as tough to groove out.

Look for it at your local friendly NAPA.

 

can/should i just weld the header? is it ceramic? can it be welded? i just want to have my car in good running condition soon since i have a long trip next week. thanks again for any help.

 

I'm pretty sure it's going to be cast iron just like any stock header out there. Grind it a bit (you'll have to anyway if you're going to fill/weld it) and boom you'll see. Just make sure you don't ruin the sensor bunghole (lol had to say it)
good luck

 

uh.... im not exactly positive... but i think that the 96-00 manifold with the cat right there is some sorta tubular metal not cast iron... like i said not exactly positive but someone correct me

 

meh... my bad its the 01 and up civics its tubular manifold... 96-00's are still cast

 

Would i be able to run an ex header, ex cat and catback on my HX without any cels?

 

Its not designed for the HX but if your state doesn't require anything crazy go for it. You'll just need to extend the secondary o2 sensor. Plenty of extended wiring harnesses sold on ebay or @HondaPartsHero can help.

 

It would trigger front oxygen sensor slow response if you have an hx with a manual transmission

 

Try a new sensor first! the manifold is known for cracking! I purchased a used one for $20 with no cracks so look for a used one until then try a new sensor because right now even though I replaced the manifold with one that wasn't cracked fast forward about 2 years later this one is already cracked but I don't have any check engine codes because of it so at least try a new sensor. Remember check engine lights pop up only from bad or worn out sensors.