Emmissions

[Fiddledeede2]

I have a 1994 atx 3.2L and it just failed its emmission test on CO. It passed the other areas easily.

Suspecting the O2 sensor, I checked the codes and they were 111 - fine. I just put in a new air filter so it wasn't that. Any other ideas before I start replacing plugs and wires.

Thanks

A

 

[Blackheart4355]

i'd try oil change and tune up including fuel filter. then try again. my 89 buick lesabre t type passed with flyin colours

 

[projectSHO89]

Check out this article: Possible Causes of Emssions Failures for guidance.

Steve

 

[Fiddledeede2]

Thanks for the advice.

Blackheart - what would you recommend that I cover in the tune-up. I am overdue for my 60K so I need to do that but don't want to until the weather warms up in a month or two. Do you think that an oil change, fuel filter, and an idle adjustment would cover it.

Steve - great article. It made me think of one more thing. My car runs very cold. The temperature gauge barely gets into the normal range. Do you think the thermostat is gone - is there any way to tell.

Thanks

 

[Dr. Tweak]

You probably want to add plugs and wires to that, but don't put a set of new wires in if you have oil in the plug wells!

<small>[ March 08, 2004, 12:45 AM: Message edited by: JDLangevin ]</small>

 

[projectSHO89]

Fiddledeede2:
Thanks for the advice.

Steve - great article. It made me think of one more thing. My car runs very cold. The temperature gauge barely gets into the normal range. Do you think the thermostat is gone - is there any way to tell.

Thanks

The cold running (if your guage reading is accurate) is likely the cause of your high CO readings.

A stuck-open thermostat is an extremely likely (but not only) reason for that.

Personally, I would replace the thermostat, the ECT, and the temperature guage sending unit all at one time. Your total cost for parts would be less than $40, you would only have to open the cooling system once, and you would have a much better chance of passing your emissions test. This would also be the perfect time for a coolant flush if one is needed.

Steve

<small>[ March 08, 2004, 07:20 AM: Message edited by: projectSHO89 ]</small>

 

[Fiddledeede2]

Hi,
I replaced the thermostat - now the car operates at around the L (I've heard that is not unusual). It did get to the M at one point so I think it is fine.

I went back to the emmissions and it failed the CO again. It was worth doing the thermometer anyway because my consumption sucks. I tried to replace the Temp sending unit but it was hard to get at. It is on the LHS of the thermostat housing and it looks like a wire with a bolt going into the manifold. There are all sorts of wires in the way.

One of you suggested a general tune up and that may make sense since my idling is very rough. Do you think that cleaning the IAB and doing an idle reset would help the emmissions at all. Once again if it helps the idling, it's worth doing anyway.

I have the plugs and wires ordered but they have not arrived yet and I am running out of time to pass this emmissions test or else I will be driving around unregistered. At some point I am probably going to have to breakdown and take it into someone to fix.

By the way, if an O2 sensor is bad, would it definitely throw a code. I am pretty sure I had one replaced 2 1/2 years and 20K miles ago.

Any other ideas would be appreciated.

 

[musiccitysho]

I take it you have no CE light, is your car running right?, no knocking or anything? I passed the TN emissions with a K&N, a Hi flow catback and a occasional 172/176 lean code. Is there any chance you have a chip installed that may be altering you A/F mixture?
One other thought, was your car good and heated up, that will help burn the gases more efficiently.
If it helps my emisions data was
HC...33 PPM limit..220
CO...0.04% limit..1.20
CO2...14.85%
Also I dont know if it really works or not but I saw a fuel additive at O'reily's or autozone that said "it was guaranteed" to help cars pass the emissions tests...maybe something to check out wink
Hope this can be of some help

<small>[ March 13, 2004, 12:32 AM: Message edited by: musiccitysho ]</small>

 

[Fiddledeede2]

Thanks for the input -
No CE light coming on, no codes, no knocking but runs rough
Doubt there is a chip installed affecting the A/F
The car was heated up - I drove it a solid 30 minutes (hwy and in town) before the test.

I am at a loss. I guess it is going into the shop on Monday.

 

[Fiddledeede2]

Great News. Just passed the emmissions test. It really needed the plugs and wires. I found a great shop (in North Atlanta) who did it for me They also replaced all the gaskets (oil in wells) for under $900. I'm happy - at 80K, it needed to be done, I just needed the push.

Thanks all
Fiona

 

[sdpatt]

For the record, tired, old oxygen sensors can perform the lean-rich switching too slow and result in greater HC and CO emissions and the resulting lower fuel economy. They can do this without throwing any error codes. They should be replaced at the same interval as the spark plugs or 60,000 miles.

 

[musiccitysho]

I was just wondering why you never mentioned that you had oil in your plug wells at anytime in your post? It would have made diagnosing your failed emissions and rough idle a "no brainer" with a lot less speculation and a lot more constructive advice.
Though I am happy to hear everything turned out well for you and your emissions and drivability issues were resolved.