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Emissions CO Inspection Fail Texas

2K views 2 replies 3 participants last post by  Old4X 
#1 ·
I failed inspection on the CO readings. Here is a breakdown: HC 190 High Speed and 182 Low Speed (Pass). C0(%) 3.53 High Speed and 2.98 Low Speed (Both Failed). C02 (%) 12.1 High and 12.5 Low. 02 (%) 0.2 High Speed and 0.2 Low Speed. NOx (ppm) 882 High and 1122 Low (Pass). Dilution (%) 15.6 High Speed and 15.5 Low Speed.

I put a Motorcraft carb on since last inspection. I think the cat and PCV valve is still good and the jeep has NEVER run better than it does now. Of course with the Motorcraft carb just about all of the vacuum lines went into the trash can.

The only weird thing going on with the jeep is a high pitched whistling sound when the jeep initially accelerates under load. Almost can't be a vacuum leak unless it's in the throttle body somewhere. I may have a manifold leak? Who knows, and if it's not related to the CO reading then I can live with it at this point.

Can anybody give me a checklist of things to try?

Thanks you for your help.
 
#3 ·
Try rejetting to the next smaller jet size. When you re-tune tthe carb, set the idle 50 rpms on the lean side of peak.

Make sure your EGR system is working.

Get an air filter that has the proper flow rate for that engine.

Put an OEM spec thermostat in the cooling system.

Fix your vacuum leak, a whistle is telling you there is one.

If you don't know the Cat's history, get a new one.

Change the oil just before your next inspection.
 
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