Failed E-test in Canada

[targa88]

First off- totally stock car(1988)- passed two years ago ( last test). However, I suspect that the high octane gas used for track days has "clogged" the O2 sensor.Which is causing the over limit C02 readings.
By process of elimination, the spark plugs appear, so the next component would be the sensor. I have emptied the fuel tank of the high octane gas, and will proceed will lower octane.
1) IS there any way of cleaning the O2 sensor?
2) IF not, how complicated is the replacement? Are there any speciality tools required (I think that I read 22mm crows foot wrench)?
3) Any secrets, I need to know before starting?
Much appreciated.

[johnsjmc]

A lazy O2 sensor will usually raise th HC values also. They are easy to change as they are threaded into the exhaust sytem just ahead of the Cat.Often tight on removal from rust be careful not to round the nut off.I don,t know of a sucessful cleaning method and apply a little antiseize to the new threads if not already there.

[stlrj]

Sometimes just setting the mixture to spec, assuming it's rich, and driving it that way for a while might clean things up enough to bring a lazy, tired, lifeless old 02 sensor back to life.


74 w/86 3.2 transplant
Redwood PCA

[johnsjmc]

The 88 Carrera with DME or motronic isn,t adjustable as in the earlier CIS systems like the SC used. The Canadian e test warms up the O2 sensor with an initial 90 sec run on the dyno and the sensor itself is electrically heated . A good fast run may burn off a few deposits but each failed retest is going to cost you to find out if it made enough difference. How far off from a etest pass are you?

[dvkk]

You need to post all the numbers.
If the race gas you were using was leaded, it will have killed your O2 sensor. CAT too.

[Porsche_monkey]

Post your results.

[targa88]

First test results (coming out of six month storage):
Curb idle test passed with more than adequate margin.

ASM 2525 Test
HC ppm 48 (limit 66)
CO .46 (limit .37)
NO ppm 588 (limit 757)
RPM 1783

Second test after DEW (using 94 octane gas Sunoco)
HC ppm 42
CO .46
NO 946
RPM 2443

[johnsjmc]

NOx appears high and CO as previously mentioned. NOx is caused by high temp /pressure combustion.The usual strategy to control NOx is retarded timing and exhaust gas recirculation before the Catalyst further reduces it. Is your gas stale?Stale gas will allow inaudable detonation which sends NOx up. Was the test immediately after storage? If so retest with fresh premium pump gas.If fresh gas was in use then the O2 sensor could explain the high CO reading but not usually the NOx Have you altered the base timing?It should be set at the recommended point on the tune up sticker under the hood.

[targa88]

The high NOx figures were with the 94 octane gas (fresh from the Sunoco pump) from a weekend of DE.
Everything on this car is stock

[copper]

Betcha can't wait til you don't have to smog it anymore three years from now...



I'm sure my 69 would never pass, but then the MTO knows that, and they wouldn't get the licencing fees instead of the $37 for the Etest...

[targa88]

Copper,
Ain't that the truth. Hope your "fun run" works out this weekend. Sorry I could not attend - maybe next time...

[copper]

You'll be missed. But enjoy the weekend nonetheless...

We'll catch you on another one.

Jim

[targa88]

The "Glen" beckons courtesy of Niagara regions. Tends to be less crowded than the Zone 1 event.

[copper]

Take some pics and video. If you need a stretch break on your way out there, give me a call when you're going through london.

Jim