Failed Emission Test

Hi All,
I took my 93 Corolla in for an inspection last week and it failed the
emission test. The NOx levels both for high speed and low speed were
high. I then took my car to a shop to get the catalytic converter
replaced. However, when I went back to the inspection station to get
it re-inspected yesterday, not only it still failed, but the failing
levels were even higher than the first inspection. Can someone please
tell me what the problem is?

Thanks,
Kenny

kenny_frohlich wrote:[color=blue]
> Hi All,
> I took my 93 Corolla in for an inspection last week and it failed the
> emission test. The NOx levels both for high speed and low speed were
> high.[/color]
================
Check the EGR vavle.

kenny_frohlich wrote:[color=blue]
> Hi All,
> I took my 93 Corolla in for an inspection last week and it failed the
> emission test. The NOx levels both for high speed and low speed were
> high.[/color]
================
Check the EGR valve.

"kenny_frohlich" <kenny_frohlich@yahoo.com> wrote in message
news:1156631451.671884.51450@i42g2000cwa.googlegroups.com...[color=blue]
> Hi All,
> I took my 93 Corolla in for an inspection last week and it failed the
> emission test. The NOx levels both for high speed and low speed were
> high. I then took my car to a shop to get the catalytic converter
> replaced. However, when I went back to the inspection station to get
> it re-inspected yesterday, not only it still failed, but the failing
> levels were even higher than the first inspection. Can someone please
> tell me what the problem is?
>
> Thanks,
> Kenny
>[/color]

What are the other readings for the emissions tests, ie., Hc, CO?

I would check EGR and MAP sensor operation, depending on the results of the
test.
--

Ray O
(correct punctuation to reply)

[toyomoho]

High NOx levels are also caused by high combustion temps. Things like high coolant temp, a really lean air/fuel ratio (manifold system leaks), O2 sensor improper operation, EGR system problems (VSV, modulator, hoses), improper timing and spark advance.

Ray O wrote:[color=blue]
> "kenny_frohlich" <kenny_frohlich@yahoo.com> wrote in message
> news:1156631451.671884.51450@i42g2000cwa.googlegroups.com...[color=green]
> > Hi All,
> > I took my 93 Corolla in for an inspection last week and it failed the
> > emission test. The NOx levels both for high speed and low speed were
> > high. I then took my car to a shop to get the catalytic converter
> > replaced. However, when I went back to the inspection station to get
> > it re-inspected yesterday, not only it still failed, but the failing
> > levels were even higher than the first inspection. Can someone please
> > tell me what the problem is?
> >
> > Thanks,
> > Kenny
> >[/color]
>
> What are the other readings for the emissions tests, ie., Hc, CO?
>
> I would check EGR and MAP sensor operation, depending on the results of the
> test.
> --
>
> Ray O
> (correct punctuation to reply)[/color]

Ray,
Other readings are passing and they are:
HC: 22
CO: 00
CO2: 13.5
O2: 1.3
Dillution: 13.5

By the way, I know the EGR valve looks like a flying sauce thing, but I
can not seem to locate it under the hood. Can you please tell me where
I can find it (This is a 93 Corolla)?

Thanks,
Kenny

"kenny_frohlich" <kenny_frohlich@yahoo.com> wrote in message
news:1156685499.120084.18320@74g2000cwt.googlegroups.com...[color=blue]
>
> Ray O wrote:[color=green]
>> "kenny_frohlich" <kenny_frohlich@yahoo.com> wrote in message
>> news:1156631451.671884.51450@i42g2000cwa.googlegroups.com...[color=darkred]
>> > Hi All,
>> > I took my 93 Corolla in for an inspection last week and it failed the
>> > emission test. The NOx levels both for high speed and low speed were
>> > high. I then took my car to a shop to get the catalytic converter
>> > replaced. However, when I went back to the inspection station to get
>> > it re-inspected yesterday, not only it still failed, but the failing
>> > levels were even higher than the first inspection. Can someone please
>> > tell me what the problem is?
>> >
>> > Thanks,
>> > Kenny
>> >[/color]
>>
>> What are the other readings for the emissions tests, ie., Hc, CO?
>>
>> I would check EGR and MAP sensor operation, depending on the results of
>> the
>> test.
>> --
>>
>> Ray O
>> (correct punctuation to reply)[/color]
>
> Ray,
> Other readings are passing and they are:
> HC: 22
> CO: 00
> CO2: 13.5
> O2: 1.3
> Dillution: 13.5
>
> By the way, I know the EGR valve looks like a flying sauce thing, but I
> can not seem to locate it under the hood. Can you please tell me where
> I can find it (This is a 93 Corolla)?
>
> Thanks,
> Kenny
>[/color]

This California Smog Check web site lists common causes for emissions
failures: [url]http://www.smogsearch.com/index.php?page=faq[/url]

A lean mixture could be due to a bad O2 sensor or clogged injectors. Check
ignition timing to make sure it is not too advanced (are you getting any
knocking/pinging on acceleration?)

Not all vehicles have an EGR valve. I don't recall if yours does nor not.
The EGR valve is generally located near the intake manifold with a pipe
leading to the exhaust manifold.
--

Ray O
(correct punctuation to reply)

kenny_frohlich <kenny_frohlich@yahoo.com> wrote:
[color=blue]
> By the way, I know the EGR valve looks like a flying sauce thing, but I
> can not seem to locate it under the hood. Can you please tell me where
> I can find it (This is a 93 Corolla)?[/color]

If you have a 49 state version you need to find a California model first.
Then it should be easy to find. :-)