Emissions failed subaru with standalone..

[dennieboy96]

Dear Pistonheads ,

the last 2 weeks i am trying to get my subaru thru APK (dutch MOT) but it fail's on CO. The CO is around 1.00 and should be below 0.3. lambda was good enough between 0.97 and 1.03 but fluctuates a lot.

My Subaru is running an EMU standalone ECU with a maffless setup. I recently added a Bosch LSU 4.2 Wideband. The Wideband sensor made the lamba good enough but still not the CO. is there a way to fix this? i can controll every thing in the ECU but don't know what to change to make it run cleaner.

hope you guy's could help me

[GreenV8S]

If the lambda readings are fluctuating that'll make it harder to meet any emissions limits.

I assume that target is for a car with cats. Do you still have a cat fitted? Is it working (not contaminated while you were sorting out your new ECU)? Was the cat up to temperature when tested? Make sure the engine isn't being fed breather gases. Make sure the oil filter and and intake is free of oil. Make sure the engine itself is up to temperature when tested. In general, high CO suggests the engine has excess fuel so you probably want to go a fraction leaner, but if the engine isn't running cleanly then all bets are off. Make sure the plugs are clean. If you have colder than normal plugs, consider fitting hotter ones for the test. Consider whether there might be variation between cylinders e.g. air leaks or air/fuel distribution problems making some rich and some lean. If the engine hardware is completely standard you might be able to rule that sort of thing out, but perhaps you changed the ECU because the engine's fuel requirements have changed in which case you need to consider whether any of your changes could affect emissions. A CO meter isn't particularly expensive and would be a great help when you're trying to sort the emissions out.

[Mignon]

Have you asked yourself how it is possible for the CO to be rich but the lambda to be normal? If you understood the answer to this you would understand what is wrong with the engine. You might want to read the penultimate comment in this thread.

https://www.pistonheads.com/gassing/topic.asp?h=0&...

[dennieboy96]

GreenV8S said:

If the lambda readings are fluctuating that'll make it harder to meet any emissions limits.

I assume that target is for a car with cats. Do you still have a cat fitted? Is it working (not contaminated while you were sorting out your new ECU)? Was the cat up to temperature when tested? Make sure the engine isn't being fed breather gases. Make sure the oil filter and and intake is free of oil. Make sure the engine itself is up to temperature when tested. In general, high CO suggests the engine has excess fuel so you probably want to go a fraction leaner, but if the engine isn't running cleanly then all bets are off. Make sure the plugs are clean. If you have colder than normal plugs, consider fitting hotter ones for the test. Consider whether there might be variation between cylinders e.g. air leaks or air/fuel distribution problems making some rich and some lean. If the engine hardware is completely standard you might be able to rule that sort of thing out, but perhaps you changed the ECU because the engine's fuel requirements have changed in which case you need to consider whether any of your changes could affect emissions. A CO meter isn't particularly expensive and would be a great help when you're trying to sort the emissions out.

The car has a cat and needs 1 for the emissions test. The cat has 2 weeks before i started to do mine helped a car get through the emissions. The test where done at 90 degrees oil tempreture and after a drive of a couple of minutes. plugs are indeed 1 degree colder and are brand new got the same in al my subaru's. But the breader gasses is maybe a possibilty because i have an oil like which some times smoke right under the air filter.. but not constant.

[McVities]

dennieboy96 said:

The car has a cat and needs 1 for the emissions test. The cat has 2 weeks before i started to do mine helped a car get through the emissions. The test where done at 90 degrees oil tempreture and after a drive of a couple of minutes. plugs are indeed 1 degree colder and are brand new got the same in al my subaru's. But the breader gasses is maybe a possibilty because i have an oil like which some times smoke right under the air filter.. but not constant.

Smoke entering the engine through the air intake will not provide enough hydrocarbons to make the engine run rich.......especially as there is no MAF now to make dirty.
Have a read of the link posted my Mignon........I would agree with the conclusions - you have an air leak in the exhaust. It is letting fresh air INTO the exhaust and fooling the lambda, causing the engine to run rich with a normal(ish) labda reading.