97 SSEi with 185,000 miles, everything passed with flying colours except for:

No PPM, Limit is 408 Results were 664 therefore it failed. Test was done at 1417 rpm with stated dilution at 15.1.

Pamphlet states possible problems as:

High NOx on driving Test

- Inoperative or ineffective EGR (Exhaust Gas Recirculation) system
- Excessive lean air/fuel ratio
- Inoperative or missing catalytic converter (three way catalytic)
- Excessive spark advance
- Faulty Thermostatic Air Cleaner (TAC) system
- Engine Deposits (Carbon)
- Engine Mechanical defect(*)

Air cleaner was new and oil & filter just changed at time of test and I couldn't find any visable signs of vacuum leaks or crackes hoses. Car was at operating temperature of 195 F when driven to the test center and engine light was no one nor were there any codes stored.

Plugs from previous owner were A/C irrudium with gap set at 65 and I've since replaced them with NGK gap at 55.

How do you properly visually check or clean the EGR Valve or even the 02 Sensor and any other suggestion on lowering the NO ppm within acceptable levels?

PS. I don't have a scanner available but a fellow member scanned it last week before the test.


Thanks

If it was EGR, PCM would say so.
You have no TAC
Spark Advance is computer corrected

That leaves the cat, the O2, and carbon deposits. Sea Foam it to remove the deposits. Replace that front O2, and regap your plugs to 60.

If I may ask a couple questions?

I believe there are 2 O2 sensors in the 97 i therefore if there was a problem with the Cat wouldn't the O2 sensor behind the Cat sence this problem and possibly through a code?

If there was a problem with the front O2 sensor wouldn't that through a code also?


Based on your advice, I will regap the plugs to 60.
Purchase seafoam to clean engine deposits.
Price out the O2 sensor as it would appear I may most likely need to change it.

Any way to check the O2 sensor if I remove it?

Thanks sandrock

Had same problem with my 98. Turned out to be the o2 sensor. I have 315 000 on mine and ran 94 octane for about two weeks before the second etest just to reduce the chances of a carbon build up fail. took it in and everything passed flying colours. no gaurentee but thats what worked for me.

If you had a bad O2 sensor 98bonnie_ssei did it through a code? Is that how you knew it needed replacement?

I may be wrong, But I don't beleave O2 sensors to throw codes,they just read alittle bit "off", at least thats my experiance (but thats with OBD1 cars)

They only throw codes when they're well-done, not medium or medium-rare.

They get tired after about 50-60k.

Yup. They wont throw codes unless they are dead or near death. But that doesn't mean what is in there right now is good either.

Do the seafoam for combustion chamber cleanup. That will get rid of carbon buildup. I think having those plugs gapped too short has something to do with it too.

Not sure where to get Seafoam in Ontario but I'll check, as for the plugs the A/C irridium plugs set at 65 were installed at the time of the emissions test. I have since installed NGK platinum at 55.

Thanks for the info Will.


Peter, where'* the best place around us to get a good price on an A/C Delco O2 Sensor?

Each time I go back to redo the test it cost me therefore I want to cover as many bases as I can before I pay for the next retest.


Thanks

you can get Seafoam from NAPA here in ontario

and as for the A/C Delco O2, like the last two I got, and the last one you got... I get them from work.

if your willing to wait, I have noticed www.Rockauto.com has great prices for A/C delco stuff

EDIT: two near the bottom http://www.rockauto.com/catalog/x,ca...,parttype,5132