Got Failed Emission Test

hrm · August 18, 2012

Hi guys,

Today I went to do the anual emission test and got failed. Car is a 1994 Lancer with Carb 4g15 engine. what they said was that at idle it emits more CO and asked to increase air supply to carb (as I understood). also said air filter could not be at fault here.

Results: @ idle CO 5.59 %(standard 4.5%) - Fail

@ 2500 CO 0.31% - Pass

No issues with HC. I serviced tha car about 2 months ago and replaced both oil and air filters and didn't had any trouble with the engine since then. But didn't do a tune up recently. Is this could be the case? What should I be looking for?

Thanks.

Edited August 19, 2012 by hrm

Davy · August 18, 2012

Hi hrm,

Sorry to hear that your car didn't make the test. If you could go to a garage today and get your car properly tuned, you can submit the car for the emission test again today for no additional charge.

And I think you mean CO (Carbon Monoxide) and not CO₂(Carbon Dioxide). This could be due to a couple of reasons and according to the information you have given, it looks as if the air to fuel ratio is messed up in your carburetor disallowing a complete combustion (less air, more fuel). So the guys at the emission testing facility were correct.

Also, make sure you drive the car a couple of Kilometers before going for the test (just saying in case the place is very close to your home) to bring it to the operating temperature, as this could be a reason for High CO levels as well.

Hope this helps. Good luck!

Edited August 18, 2012 by Davy

hrm · August 18, 2012

On 8/18/2012 at 9:20 AM, Davy said:

Hi hrm,

Sorry to hear that your car didn't make the test. If you could go to a garage today and get your car properly tuned, you can submit the car for the emission test again today for no additional charge.

And I think you mean CO (Carbon Monoxide) and not CO₂(Carbon Dioxide). This could be due to a couple of reasons and according to the information you have given, it looks as if the air to fuel ratio is messed up in your carburetor disallowing a complete combustion (less air, more fuel). So the guys at the emission testing facility were correct.

Also, make sure you drive the car a couple of Kilometers before going for the test (just saying in case the place is very close to your home) to bring it to the operating temperature, as this could be a reason for High CO levels as well.

Hope this helps. Good luck!

Thanks Davy !. It is CO not CO2. will do a tune up and try again. Btw I can re take the emission test for free until 60 days from today's check.

Rohnd · August 18, 2012

In Carburator engines the causes of excessive CO at idle speed are (if the CO @ 2500 rpm OK)

1. Idle adjustment not answering to variable positioning of related screw.

Cause - Related passages are blocked due to contaminations.

Remedy - Clean up the Carburator

2. PCV system malfunctioning.

Causes - PCV Valve not functioning, Attached tubes leak.

Remedy: Check and repalce above.

Other general tune-ups wont help in this regard.

hrm · August 18, 2012

@Rohnd

Thank for the advice bro. Do PCV valves exist in My car too? coz it has SU type carb and heard they have a port instead of the valve. And also does this mean a regular carb mechanic wouldn't be able to solve this issue?

Rohnd · August 18, 2012

On 8/18/2012 at 12:09 PM, hrm said:

@Rohnd

Thank for the advice bro. Do PCV valves exist in My car too? coz it has SU type carb and heard they have a port instead of the valve. And also does this mean a regular carb mechanic wouldn't be able to solve this issue?

The PCV valve is usually fitted on the crank case cover which links to carb/inlet manifold. A good carb mechanic should be able to solve the issue,

VVTi · August 18, 2012

Check your vacuum lines as well. How about the plug condition?

hrm · August 18, 2012

On 8/18/2012 at 3:47 PM, VVTi said:

Check your vacuum lines as well. How about the plug condition?

replaced all 4 plugs in the last service 2 months ago.

hrm · August 19, 2012

Today I took the car to a place in Koswatte and got done the following:

1. Removed and cleaned the Carb

2. Cleaned all 4 plugs

3. Cleaned distributor and cap

4. Adjusted Idle circuit - actually there's nothing much to change here

In all the cases what the mechanics said was the parts are clogged with oxides/carbons/dust etc. will re take the emission test next weekend.

Rohnd · August 20, 2012

On 8/19/2012 at 3:01 PM, hrm said:

Today I took the car to a place in Koswatte and got done the following:

1. Removed and cleaned the Carb

2. Cleaned all 4 plugs

3. Cleaned distributor and cap

4. Adjusted Idle circuit - actually there's nothing much to change here

In all the cases what the mechanics said was the parts are clogged with oxides/carbons/dust etc. will re take the emission test next weekend.

1. You said removed and cleaned the carb - does it mean clean the carb using a repair kit or just the outside/inside cleaning.

The latter won't give expected results sometimes,

4. Adjusted Idle circuit - Do you mean Idle Air/fuel ratio adjustment or just the idle speed adjustment . The latter won't give a solution to your problem.

If you did carb clean up using a repair kit and if the idle air/fuel ratio adjustment is answerable , you may have attained the solution.

Edited August 20, 2012 by Rohnd

hrm · August 20, 2012

Well didn't used a repair kit in cleaning the carb. But did air/fuel ratio adjustment

Rohnd · August 22, 2012

On 8/20/2012 at 4:53 PM, hrm said:

Well didn't used a repair kit in cleaning the carb. But did air/fuel ratio adjustment

Hope that the correct cleaning has not been performed. However if you are satisfied with the answering

(ie; RPM is changing/the engine vibrating/stalls etc,within limits when adjusting ) of idle air/fuel mixture

adjustment, You may try the emission test again. but keep in mind that correct idle CO measure

can only be obtained for this adjustment with a CO meter in a well equipped workshop,

hrm · August 25, 2012

Update :

Today I took the car to re take the emission test after tune-up and got passed.

Results: @ idle CO 0.28 %(standard 4.5%) - Pass

@ 2500 CO 0.31% (standard 4.5%) - Pass

I think these figures are very much satisfying for a car of this age and it's a big relief for me. Thanks for all the guys who spent their time to give some valuable advices on this.

Thanks again people

Edited August 25, 2012 by hrm

Rohnd · August 25, 2012

On 8/25/2012 at 6:19 AM, hrm said:

Update :

Today I took the car to re take the emission test after tune-up and got passed.

Results: @ idle CO 0.28 %(standard 4.5%) - Pass

@ 2500 CO 0.31% (standard 4.5%) - Pass

I think these figures are very much satisfying for a car of this age and it's a big relief for me. Thanks for all the guys who spent their time to give some valuable advices on this.

Thanks again people

Glad to hear you released from the problem. Very good 0.26% against 4.5% CO. However we follow levels used in

England 22 years back. We need something to tax,so we still follow rules than the norms. For newest cars it is 0% ,

at the exaust.

hrm · August 25, 2012

On 8/25/2012 at 3:24 PM, Rohnd said:

Glad to hear you released from the problem. Very good 0.26% against 4.5% CO. However we follow levels used in

England 22 years back. We need something to tax,so we still follow rules than the norms. For newest cars it is 0% ,

at the exaust.

Agreed mate !!!

djpra123 · August 27, 2012

Hi HRM..Can you please let me know the place you went to. My car with EFI engine failed with CO levels about 8.000 something. Do they service EFI engines too?

hrm · August 27, 2012

On 8/27/2012 at 4:03 AM, djpra123 said:

Hi HRM..Can you please let me know the place you went to. My car with EFI engine failed with CO levels about 8.000 something. Do they service EFI engines too?

I think yes. It's R*yal A*to S*rvice in front of Thalangama hospital, Koswatte