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Matt Timion 07-09-2006 03:47 PM

Just failed emissions twice
 
My wife's CRX is due for renewal. We took it in for emissions and safety the other day. The emissions as 10mph passed, but failed at 25mph. It failed on the NOx, and was over by around .3 (should be .9, read at 1.2).

I replaced the sparkplugs, warmed up the car and took it back.

This time it was over 2.0 at both 10mph and 25mph. It was also overheating like crazy. YOu try driving home with the heater on in 90+ degree weather in the desert... argh.


Anyway, the next shot is to replace the o2 sensor. I'll use the one from my civic as I don't need it any more. The guy said that my new plugs might not be gapped properly, but I was hoping that wasn't the issue b/c I bought the "pre-gapped" ones. That's what I get for spending extra money on spark plugs.

Can anyone think of what might cause high NOx emissions? Is it possible that it's time for a new catalytic converter?

SVOboy 07-09-2006 03:49 PM

Is it possible to give her your second cat when you hook up your test pipe?

GasSavers_maxc 07-09-2006 03:56 PM

Quote:

Originally Posted by Matt Timion
My wife's CRX is due for renewal. We took it in for emissions and safety the other day. The emissions as 10mph passed, but failed at 25mph. It failed on the NOx, and was over by around .3 (should be .9, read at 1.2).

I replaced the sparkplugs, warmed up the car and took it back.

This time it was over 2.0 at both 10mph and 25mph. It was also overheating like crazy. YOu try driving home with the heater on in 90+ degree weather in the desert... argh.


Anyway, the next shot is to replace the o2 sensor. I'll use the one from my civic as I don't need it any more. The guy said that my new plugs might not be gapped properly, but I was hoping that wasn't the issue b/c I bought the "pre-gapped" ones. That's what I get for spending extra money on spark plugs.

Can anyone think of what might cause high NOx emissions? Is it possible that it's time for a new catalytic converter?

Is the egr valve working. That's for NOx.

Matt Timion 07-09-2006 04:03 PM

Quote:

Originally Posted by SVOboy
Is it possible to give her your second cat when you hook up your test pipe?

I was actually just thinking about that. I might do it if the next plan fails.

High NOx apparently means it's running lean, which is also shown by it always overheating. Perhaps the new O2 sensor will fix it. Thanks for the 411 bagpipe goatee.

Matt Timion 07-09-2006 04:04 PM

Quote:

Originally Posted by maxc
Is the egr valve working. That's for NOx.

I'm unsure if they had EGR valves in 87. Since my 89 doesn't have one I think they didn't have EGR valves. I'll double check though.

SVOboy 07-09-2006 04:07 PM

The only civics that got egr until 01 were the FE models, and I think the crx is an si, so I doubt it'd have it.

krousdb 07-09-2006 04:16 PM

Clogged injector? Low fuel pressure?

SVOboy 07-09-2006 04:24 PM

Hey, I suggested low FP also!

Anyway, I hope I live to be old enough to see a clogged injector on a honda, but Iono, seems improbable, :p

GasSavers_Ryland 07-09-2006 07:44 PM

the 180F thermostats are stock for reduced nox emissions, if you are running a 192 thermostat for better mpg it's going to hamper your emissions test.

the side gaped/pregaped plugs don't alwas agree with honda's, I've had best luck with NGK plugs, they only last 15,000 miles, but the copper core conducts better then platnum, altho platnum never wears out.

try running some fuel system cleaner if you haven't already.

if you have an EGR valve it will be listed on yoru under hood lable, my 85 crx hf has an egr valve, along with my 84 civic hatch back.

MetroMPG 07-09-2006 08:48 PM

Also, is it running hot because it's lean, or is it lean because it's running hot? If you know what I mean.


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