Failed smog. Update: failed the 2nd test :(

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alphatarget1

Diamond Member
Dec 9, 2001
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96 accord. High HC, CO and NO...

The car runs fine. I think the platinum plugs were put in like, 30k miles ago so I don't see how they could be bad, plus the car drives fine. I'll check regardless. No CEL on so presumably the O2 sensors work.

EDIT: failed the 2nd time.

Replaced O2 sensors and PCV valves. I think the car ran a little better afterwards, but the emission numbers didn't get any better. I'm starting to think that my cat needs replacing, since the car used to spit out water vapor in the exhaust pipe and it doesn't do that anymore. I fly back tomorrow and ran out of time... will just have to get a shop to replace the cat.
 
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Vette73

Lifer
Jul 5, 2000
21,503
9
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How many miles?


But a bad Cat., EGR, or O2 sensors can cause your problems. EGR would usually throw a code. But a bad O2 sensor may not. It could look right but be reading wrong. So the computer adjust incorrectly. So if its over 100k and you have never changed the O2 sensors then start there and disconnect the battery when you change them.
 
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Pacfanweb

Lifer
Jan 2, 2000
13,158
59
91
The plugs should be running BETTER right now, if anything, after 30k....the gap should have increased a little, which will actually drive UP the coil voltage...and since they'll still be well within the designed specs for your coil, you'll have a bigger, stronger spark now than when they were installed.

Try what Marlin recommended. Make sure the engine is in the best possible state of tune......how about the plug wires? (if it has them)
 
NutBucket

NutBucket

Lifer
Aug 30, 2000
27,152
635
126
For future reference I would suggest going to OEM NGK plugs. They are always the best choice.

I too would start with the O2 sensor....but the simplest thing you've overlooked is a cold cat. Many times smog places won't get the cat hot enough. I've had experiences with an older cat where it would fail the first run. Revved it for a bit and it passed a re-test. Even if you drive it hard to get things nice and hot just having it sit for 5 minutes at the shop could cause the temp to drop too far.
 
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alphatarget1

Diamond Member
Dec 9, 2001
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Car has 180k miles.

Here is how it failed...

@15 mph, HC 87 ppm, CO .53 ppm, NO 958 ppm
@25 mph, HC 76 ppm, CO .47 ppm, NO 826 ppm

It passed 4 years ago at 129k miles.
@15 mph, HC 25 ppm, CO 0.01 ppm, NO 168 ppm
@25 mph, HC 24ppm, CO 0.01 ppm, NO 284 ppm

The ECU was changed recently from a working unit, although that could be a problem. O2 sensors have never been replaced. I'm wondering if the Catalytic converter could deteriorate and be bad? I'll probably start with the O2 sensor... although I was under the impression that if the O2 sensors are bad, then the engine wouldn't run right and it'll start throwing codes.
 
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alphatarget1

Diamond Member
Dec 9, 2001
5,710
0
76
NutBucket said:
For future reference I would suggest going to OEM NGK plugs. They are always the best choice.

I too would start with the O2 sensor....but the simplest thing you've overlooked is a cold cat. Many times smog places won't get the cat hot enough. I've had experiences with an older cat where it would fail the first run. Revved it for a bit and it passed a re-test. Even if you drive it hard to get things nice and hot just having it sit for 5 minutes at the shop could cause the temp to drop too far.
Click to expand...

I think the guy tested it twice. I drove to the bank, and then to the shop to get it tested. Less than 3 miles driven total, and it's kind of chilly this morning (60 F).
 
DivideBYZero

DivideBYZero

Lifer
May 18, 2001
24,117
2
0
alphatarget1 said:
I think the guy tested it twice. I drove to the bank, and then to the shop to get it tested. Less than 3 miles driven total, and it's kind of chilly this morning (60 F).
Click to expand...
Take it on a highway run for no less than 30 mins then test it. I bet the results will be drastically different.
 
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Vette73

Lifer
Jul 5, 2000
21,503
9
0
alphatarget1 said:
Car has 180k miles.

Here is how it failed...

@15 mph, HC 87 ppm, CO .53 ppm, NO 958 ppm
@25 mph, HC 76 ppm, CO .47 ppm, NO 826 ppm

It passed 4 years ago at 129k miles.
@15 mph, HC 25 ppm, CO 0.01 ppm, NO 168 ppm
@25 mph, HC 24ppm, CO 0.01 ppm, NO 284 ppm

The ECU was changed recently from a working unit, although that could be a problem. O2 sensors have never been replaced. I'm wondering if the Catalytic converter could deteriorate and be bad? I'll probably start with the O2 sensor... although I was under the impression that if the O2 sensors are bad, then the engine wouldn't run right and it'll start throwing codes.
Click to expand...

If the O2 sensor doe snto read at all then yea it will throw a code. But if its reading is just off the computer will make adjustments based on that.
Most O2 sensors need to be replaced around 100-125k. My truck had over 160k on its O2 sensors and my tail pipe readings got much better after I replaced them.

So replace the O2 sensors and also the PCV valve (cheap and on top of the motor) if it has not been done in a while. Also a good time to check/replace fuel filter, air filter, plugwires/cap rotors, oil, and trans fluid if you plan on keeping the care for a while.

Check out rockauto.com for parts.
 
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alphatarget1

Diamond Member
Dec 9, 2001
5,710
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76
halik said:
i <3 cali
Click to expand...

Not to turn it into a P&N thread but fuck this shit. I understand that cars need to be well maintained in order to not cause too much pollution, and I have no problem fixing this. My problem is that they are requiring cars to run on a fucking dyno (shops bitched a few years back when they were required to put them in), and catalytic converters have to be CA legal. I just ordered the O2 sensors. Even if they're not bad, they're probably due for a change anyway. I wanted to order a catalytic converter on rockauto since I'm going back to TX on Saturday and I'm having the parts overnighted here, but none are CA certified. CA certified = more money.
 
NutBucket

NutBucket

Lifer
Aug 30, 2000
27,152
635
126
Actually, after a car is over 10 years old I believe you can use any cat. I could be wrong though.

EDIT: Yep, I do see there is a list of approved aftermarket cats. I was wrong :p

Also, driving normally will not necessarily get the cat hot enough. Driving at 70mph in 3rd gear for 10-15 minutes will definitely get it hot enough.
 
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alphatarget1

Diamond Member
Dec 9, 2001
5,710
0
76
NutBucket said:
Actually, after a car is over 10 years old I believe you can use any cat. I could be wrong though.

Also, driving normally will not necessarily get the cat hot enough. Driving at 70mph in 3rd gear for 10-15 minutes will definitely get it hot enough.
Click to expand...

Do cats fail due to age?
 
NutBucket

NutBucket

Lifer
Aug 30, 2000
27,152
635
126
I don't believe they do unless the car is malfunctioning in other ways which can lead to a failure. I was still running the original cat on my '91 Accord when I sold it 5 years ago. By that point, I definitely had to make sure it was hot before it would pass.
 
halik

halik

Lifer
Oct 10, 2000
25,696
1
81
alphatarget1 said:
Not to turn it into a P&N thread but fuck this shit. I understand that cars need to be well maintained in order to not cause too much pollution, and I have no problem fixing this. My problem is that they are requiring cars to run on a fucking dyno (shops bitched a few years back when they were required to put them in), and catalytic converters have to be CA legal. I just ordered the O2 sensors. Even if they're not bad, they're probably due for a change anyway. I wanted to order a catalytic converter on rockauto since I'm going back to TX on Saturday and I'm having the parts overnighted here, but none are CA certified. CA certified = more money.
Click to expand...

You definitely missed the sarcasm in my post. Never lived in Cali and have absolutely no plans to do so. Retarded state legislative process is retarded.
 
A

alphatarget1

Diamond Member
Dec 9, 2001
5,710
0
76
Marlin1975 said:
If the O2 sensor doe snto read at all then yea it will throw a code. But if its reading is just off the computer will make adjustments based on that.
Most O2 sensors need to be replaced around 100-125k. My truck had over 160k on its O2 sensors and my tail pipe readings got much better after I replaced them.

So replace the O2 sensors and also the PCV valve (cheap and on top of the motor) if it has not been done in a while. Also a good time to check/replace fuel filter, air filter, plugwires/cap rotors, oil, and trans fluid if you plan on keeping the care for a while.

Check out rockauto.com for parts.
Click to expand...

Air filter is clean, dist cap and rotor are pretty new. I'm pretty sure it's not an ignition issue. I'll change the O2 sensors and PCV valves. After replacing those I"ll get it retested.

I wish there were some way I can see if the car will pass smog test by myself.
 
AMCRambler

AMCRambler

Diamond Member
Jan 23, 2001
7,715
31
91
O2 sensors. Definitely. If there's two, which I think there might be on that year, do them both. If you're emissions are high your fuel mileage is also probably suffering because of it. You can also take the EGR valve off and clean it. Squirt some carb cleaner in there and wipe it down. The valve and diaphragm move freely. You can also try cleaning the MAF sensor in the intake too. Be very careful with it. Use carb cleaner and a pipe cleaner as the wires are delicate.
 
radioouman

radioouman

Diamond Member
Nov 4, 2002
8,632
0
0
NutBucket said:
For future reference I would suggest going to OEM NGK plugs. They are always the best choice.

I too would start with the O2 sensor....but the simplest thing you've overlooked is a cold cat. Many times smog places won't get the cat hot enough. I've had experiences with an older cat where it would fail the first run. Revved it for a bit and it passed a re-test. Even if you drive it hard to get things nice and hot just having it sit for 5 minutes at the shop could cause the temp to drop too far.
Click to expand...

I agree with NutBucket, get rid of those platinum plugs. OEM plugs are the way to go.
 
TehMac

TehMac

Diamond Member
Aug 18, 2006
9,976
3
71
halik said:
It's sarcasm, dammit!
Also it was a guess that he lives in cali.
Click to expand...

Oh lol, I was going to say...there's a lot of bureaucratic rigamoral here that doesn't make sense.

You need to have a CARB certified sticker for your cold air intake kit--really now, what genius came up with that idea? Isn't the idea of SMOG to make sure emissions of the car are fine? Who cares what the engine looks like?

Just another attempt by the leftists and their belief in government to regulate every little thing, and who suffers from this gross intervention? The same people they're trying to "protect."
 
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