my smog check result, question

[rnln]

Last year my 15mph CO% was .40, not it's .62
Last year 15mph HC(PPM) was 24, now it's 38
The smog tech told me if I do tune up, it'll do it. Well, I just did plugs, cap, rotor, and oil (brad penn) is pretty new. What cause those things go higher? Unburn/incomplete gas burn, but why?
Last year I was using NGK BP7ES. This time I am using NGK BPR6ES

Here is my NGK BP7ES looked like when I took it out last week.


Thanks.

[stlrj]

Bad ignition wires will cause your numbers to go up.

[vreference]

I believe higher CO and HC both translate to "rich" - hows your airfilter look?

[Aurel]

These numbers can be easily reduced by increasing the ignition advance at idle. More advance will make it run leaner. Maybe your advance is a little too low right now.

[psalt]

Increased ignition advance at idle increases HC emission, about 1.4% per degree. It is the entire concept behind vacuum retard. Ignition timing has nothing to do with "rich" or "lean", these are mass A/F ratio terms based on deviation from stoich (14.7:1). Elevated HC usually indicates an ignition misfire. Elevated CO is usually a result of incorrectly rich AFR and is insensitive to ignition timing at idle.

Neither of these readings are high or out of spec, what is the issue ? Variations can be due to temperature, fuel composition, testing equipment. Timing and mixture are set by the ECU on Motronics.

[Tinker]

What's the o2 numbers?

Tinker

[rnln]

At 15mph, the O2 was at 1.4, now is 1.7

regarding the air filter, I just remember I cleaned it well last year right before the smog test. This time I did take it out but it look ok so I didn't clean it.
Another thing was my car idle low, I like it. Recently, I adjusted it a little higher, still a little lower than spec.
Also, last year, I gapped the BP7ES at .032. This year, I gapped the BPR6ES at .036

[seafood10]

I had nearly the same issue and I "cleaned" my o2 sensor and that did the trick! Just take it out and heat it up with a propane torch then dunk it in a glass of water. The expanding and contraction will break the carbon off of it, you will see bits of it in the glass. I repeated the heating and cooling about 15 times, there was a lot in the middle or inside of the sensor.

[rnln]

How hot proximately did you heat it up? You stick it in close to the nozzle or at the end of the flame?
Thanks.

[seafood10]

Originally Posted by rnln

How hot proximately did you heat it up? You stick it in close to the nozzle or at the end of the flame?
Thanks.

I had the torch on high and then put the ceramic end into the flame until it got red hot then straight into the water, repeated 15 or so times. You will see small white particles fall to the bottom of the glass. Getting the pieces from inside the sensor requires a little more work. It is always recommended to buy a new one but I did this in an atempt to see if that was my issue and it was and it is still running on my car. Before the cleaning I did not pass smog and afterwards I passed with flying colors.

Just stick it into the flame and heat it up really red hot and dunk it.

[rnln]

alright, heat heat. Thanks Seafood.

[Zeke]

Why did you go with the slightly hotter plug?

[seafood10]

Originally Posted by rnln

alright, heat heat. Thanks Seafood.

alright, let me know what hapens.
Sean

[rnln]

because that is most people recommended on this board. If I don't feel any different, I will go back to the BP7ES next time.

Originally Posted by milt

Why did you go with the slightly hotter plug?

[Lee Allen]

.....is there a way to test the O2 sensor without any specialty tools (other than maybe a VOM) b4 having to replace it? The Service book I have says you need a "pinout test harness", I am hoping there is a way around that.

Any input would be great.

Also,

Is there anywhere to go for the best price on an O2 snsor if I need one?

thanks,

Lee

[Tinker]

Copied from a site a while back:

"Testing O2 sensors on the workbench.

Use a high impedence DC voltmeter as above. Clamp the sensor in
a vice, or use a plier or vice-grip to hold it. Clamp your
negative voltmeter lead to the case, and the positive to the
output wire. Use a propane torch set to high and the inner blue
flame tip to heat the fluted or perforated area of the sensor.
You should see a DC voltage of at least 0.6 within 20 seconds.
If not, most likely cause is open circuit internally or lead
fouling. If OK so far, remove from flame. You should see a
drop to under 0.1 volt within 4 seconds. If not likely silicone
fouled. If still OK, heat for two full minutes and watch for
drops in voltage. Sometimes, the internal connections will open
up under heat. This is the same a loose wire and is a failure.
If the sensor is OK at this point, and will switch from high to
low quickly as you move the flame, the sensor is good. Bear in
mind that good or bad is relative, with port fuel injection
needing faster information than carbureted systems.

ANY O2 sensor that will generate 0.9 volts or more when heated,
show 0.1 volts or less within one second of flame removal, AND
pass the two minute heat test is good regardless of age. When
replacing a sensor, don't miss the opportunity to use the test
above on the replacement. This will calibrate your evaluation
skills and save you money in the future. There is almost always
*no* benefit in replacing an oxygen sensor that will pass the
test in the first line of this paragraph."

Tinker

[Lee Allen]

Thanks Tinker, I will give this a try this weekend and see what happens (unless I am forced to do too many "honey-do" items). I will post you results.

Lee