I Need Help with Emissions?

I brought my 308 GTSi in for emissions testing today. All the smog equipment is deleted, so I knew it would be tough. I changed the plugs and checked the air/fuel mixture with my oxygen sensor and everything looks good. I also added almost 2 quarts of ethanol to a 1/4 tank of gas for a little extra help.

The first attempt the 2500 rpm HC level was 70. 200 is passing so this is great. The low speed failed because I had the idle set above 1200 rpm.

I turned the idle down and retested. This time the high speed HC was at 102, but the idle was at 1829 (limit 220). The CO was at 2.30 high rpm and 3.27 low rpm (limit 1.20) but they don't require passing that for my car.

I tried disconnecting the vacuum line to the multiplexes and capped the intake manifold, since it seems to idle smoother that way.

The retest showed High Speed HC at 151, and idle at 3264! CO was now at 2.75 high and 3.83 low rpm.

What could be causing this? The only recommended thing I didn't do was change the oil. Could that have possibly caused the numbers above? The only other thing I can think of is a low rpm misfire. The plugs and wires and extenders are new, and I installed new fuel injectors last year.

I am sure that having cat converters would help, but these numbers are astronomical, and I know of other 308s that pass the idle test without them.

Could running the methanol mixture be causing the low rpm problem? It seemed to run great at the higher rpms, although the CO was a little high.

Of course I waited until the last minute, so my registration is expiring. Please help with any suggestions!

 

Thanks for the suggestion. I can add cats in the future if I need to. Like I said in the post, I know of other properly running 308s that pass emissions at idle without cats.

My concern now is the huge difference in HC levels at idle and 2500 rpm must mean something is really wrong with the fuel or ignition system. As far as I know, the k-jet does not allow for a separate idle mixture adjustment, so if is running clean at 2500 rpm, the fuel mixture should be right at idle. Unless I am wrong about that, or there is another component that can cause such a problem.

The idle does sound a little rough, and it smells rich too. Maybe it is an ignition problem that is letting unburnt fuel into the exhaust. I don't know where to start because I don't know what ignition problem would show up at idle that doesn't show at higher rpm. I know the flywheel position sensors can be the source of ignition problems, and I am going to check them, but it seems like that is mostly at higher rpm.

I guess a weak coil might cause a problem like this, so I might try switching them out. I keep wondering if adding the ethanol to the gas could have caused a problem, but it worked great at the higher rpm.

 

I didn't know there was an idle adjustment on a K-Jet system. Can you tell me how to do it, or are there instructions somewhere I can look them up?

 

I adjusted the air/fuel mixture richer as you said. Idle did sound smoother. I took the car in for another test.

2500 RPM
HC: 212
CO: 5.6

1064 RPM
HC: 3236
CO: 7.55

I am not surprised that the High RPM HC was higher since the fuel mixture was richer, but the Low RPM stayed about the same - at fifteen times the legal limit.

I still don't see how it is possible to have such a disparity. They should be about the same, or close to it. Something has to be going very wrong with my engine at Low RPM, but I can't figure out what it is.

If there was a qualified mechanic in my area, I would bring it in to them, but there is not.

Please help if you can.