I recently picked up a 98 dakota 3.9 2wd. Anyways, I am having trouble getting this truck to pass emissions. I have tried 3 times now. Here's a rundown of what is going on.
First test:
I brought it to the testing facility hot. The results indicated a bad cat, failed hc, co, and nox at 40km/h roll miserably. Passed idle though.
Results:
40km/h
HC ppm Limit 55 Reading 96 Result:Fail
CO% Limit .31 Reading .80 Result:Fail
NO ppm Limit 612 Reading 2906 Result:Fail
Dilution 14.34
Idle
HC ppm Limit 150 Reading 107 Result:Pass
CO% Limit .7 Reading .65 Result:Pass
Dilution 13.99
Second test:
I found my original cat was hollow! I cut it off and installed a new 3 way cat. Truck passed idle, and hc and co at 40km/h roll, but failed nox while rolling. Brought truck in hot.
Results:
40km/h
HC ppm Limit 55 Reading 22 Result:Pass
CO% Limit .31 Reading .00 Result:Pass
NO ppm Limit 612 Reading 1229 Result:Fail
Dilution 14.60
Idle
HC ppm Limit 150 Reading 18 Result:Pass
CO% Limit .7 Reading .00 Result:Pass
Dilution 14.30
Third test:
In my attempt to get cooler combustion temps, I switched out to the autolite plugs equivalent to rc9lc's gapped .040", installed a 180* t-stat and flushed and refilled the cooling system. Brought truck in hot.
Failed nox a little worse than test 2. What gives?
Results:
40km/h
HC ppm Limit 55 Reading 19 Result:Pass
CO% Limit .31 Reading .00 Result:Pass
NO ppm Limit 612 Reading 1271 Result:Fail
Dilution 14.40
Idle
HC ppm Limit 150 Reading 11 Result:Pass
CO% Limit .7 Reading .00 Result:Pass
Dilution 14.10
So my conclusion is the truck is running lean, I want to try and check for vacuum leaks tomorrow again, but I haven't found any so far. How do I richen it up? The oil is new. Is there some way to rig up an egr system? Can timing be retarded? This truck has a distributor. The pcv valve seems to be cycling just fine. I need to get this truck on the road and my capri put away. I really need some help on this one.
cale
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