TEST PIPES ON 04 AND CEL

[Bashar368]

I was planning on purchasing some resonated Test Pipes but read that a couple of people with 04 models had some problems with the check engine light coming with Hi flow cats or test pipes. Is this true or these people did something wrong during the installation that caused this to happen. I was planning on some Labree test pipes because they are a block away from my office. Thank You

MY CAR 04 6MT COUPE.

04 G35 Coupe Coming May 04. 6MT

[severedties]

the reason the CEL goes on is because your O2 sensor is reading all the new unburnt fuel coming through the pipes...there is a quick fix for that which i did....go to your local pep boys and purchase 2 ( one for each o2 sensor) 1/2'' spark plug spacers. put the spacer in the test pipe first and the screw the o2 sensor into the spacer...this pulls the sensor out enough to where it seems to read just enough fuel to keep all lights off....you can do that for about $5 or i believe stillen or some company out there makes a box that you have to splice wires on....

[Bashar368]

Does this really work

[THX723]

I've never had any CEL problems w. my 04 running test pipes. I suspect those who are getting CEL may have damaged their 02 sensor in the process of installing/uninstalling. Keep in mind it takes approx. 250 miles before the ECU will finally decide a particular 02 sensory is fouled, which is then finally proceeded by the CEL.

One should never use an impact wrench for O2 sensor installation ... or go near a sledge hammer for that matter.

[jdbinspired]

I have that some problem with the check light coming on... I also tried installing those non-fouler plugs and the light still comes on... I bet I messed up my sensors... oh well...

[LivyathanZero]

i have to wonder where some of the members of this forum get their information. there are several reasons the light comes on. the major one being catalytic converter efficiency faults. the systems don't take 250 miles to set fault. the fault is stored on the first occurance. the CEL is illuminated once the fault is stored a second time consecutively. federal emissions laws control how this works. it has more to do with which emmissions software your ECU has in it. there w as a change in 2004 so some are affected by the test pipes and some are not.

[THX723]

I suspect the 'members' you are refering to is me.

Before you get ahead of yourself. I'm not advocating ALL CEL/Test Pipe cases are the cause of bad/damaged O2 sensors. I simply pointed out the possibility of that being the case and not getting a CEL within the first hundred or so miles doesn't mean you're out of the water either.

It was poor wording on my part. What I meant to say more clearly was, "it *may* take *up to* 250 miles for a particular CEL to trigger." In the case of a terminal O2 failure (but not limited to), CEL would trigger almost instananeousluy or within approx. 30 miles. But that was not within the context for which I was pointing out above. In the case of a particular scenario where the O2 sensor core have been cracked ... it could still function but out of spec. In that case, as per OBDII standard ... a significant enough differential would have been detected between the LEFT and RIGHT bank sensor and a CEL will not trigger until after a specified period of time (up to approx. 250 miles).

[LivyathanZero]

ok makes sense now. I took it literally (not just your post, I've seen the same before) and thought it was saying that is the cause of it. no harm done, just wouldn't want someone reading the boards to see any of this and misdiagnose their car.

[ajayjuneja]

So mine came on this evening, after about 100 miles of driving with the hi-flo cats. Do I just live with the light, or is there something to do about it?

[copbait]

Originally Posted by ajayjuneja

So mine came on this evening, after about 100 miles of driving with the hi-flo cats. Do I just live with the light, or is there something to do about it?

http://www.o2sensorsimulator.com/

[THX723]

Originally Posted by ajayjuneja

So mine came on this evening, after about 100 miles of driving with the hi-flo cats. Do I just live with the light, or is there something to do about it?

Just for curiousity sake ... what's your car's production date?

If you are certain you haven't damaged your O2 sensor(s), you could also try perchasing a spacer kit that pulls the 02 sensor further away from the exhaust stream. It is very cheap at approx. 5 bux each and could be found at most auto hardware places. Disclaimer: Although some people's have good luck w. this ... it may not solve your problem. Use at own disgression.

Before you say, why not just stack some washers on and call it a day ... you will need to displace the O2 sensor fairly signficantly for this to work properly. You'll have run out of threads to properly secure the sensor to the bung. The kit will not have this issues.

[ajayjuneja]

Hey Clint, my production date is 10/2003.

[THX723]

Doh ... that is when LEV2-spec ECU started. :O

I would try the 'spark plug non-fouler' trick first. It is worth a shot because it's so cheap. It does invovle a little bit of handy work, however. Or you could have a muffler shop make another bung that screws into the existing bung.

[Dan_K]

So car with production date 10/03 or later will definitely throw a cell?

[LEK]

I had my crawford hi flo cats installed by my friend at his shop. I have an 04 coupe and have driven it for over 3k miles. I haven't had a cel throw yet. *knocks on wood.*