Another emissions failure
Here's what I did:
Took 6° off the base timing map of the MSPNP 90-93. Tuned for AFR of 15.0 in the appropriate zones for the test (~1500-3000rpm, <= 50kPa). Barely passed the 25/25 test HC CO NOx read 149 0.9 1046 allow 160 0.9 1179 Failed the 50/15 test HC CO NOx read 196 1.46 1135 allow 166 0.93 1304 I don't want to reduce timing any more than it is, for fear of busting over the NOx limit. Clearly, I'm running rich (indicated by high HC AND CO) but there could be other problems. Maybe my wideband reads leaner than true? Anyway, I pretty much have to get this to pass by the weekend. Any ideas besides leaning out the load zones and trying again? |
Try a different wideband
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Ha, I wish I had the time (and $) for that
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bens? What about the fellas at DIY?
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You datalogged the emissions test dyno run right??
There's an emissions dyno w/ a 5GA in lawrenceville. I think they'll let you run for $40, but you'll either need to make an appointment or show up early and wait. |
Originally Posted by Ben
(Post 169093)
You datalogged the emissions test dyno run right??
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Originally Posted by Atlanta93LE
(Post 169080)
I don't want to reduce timing any more than it is, for fear of busting over the NOx limit.
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http://tbn0.google.com/images?q=tbn:...gn_adv-ret.gif
It's a small pic, but I'm not going to pay for a subscription to "Dieselnet." It has less of an effect than I thought, but you can see that NOx increases with decreased timing. On another note, I'm pretty sure my cat wasn't fully warmed up either. NOx shouldn't have been that high, and I didn't drive it too quickly before testing. I should have taken it on the freeway for a bit. Oh well, "passed" now. More info: "Ignition-Advanced ignition timing will raise HC emissions at idle speed and under light load. Retarding the spark will lower HC and, in many instances, the level of NOx, even if detonation is not present. Ignition timing has no direct effect on CO but can impact it by changing the rpm of the engine and the amount of throttle angle needed to maintain idle speed. A high-energy aftermarket ignition system allows the spark plug to burn for more of the crankshafts rotation, cleaning up the level of HC. Multiple-strike systems also have a positive impact on HC production. Spark-advance curve tuning, by means of adjustable vacuum-advance units and spring kits, is essential for any drive-cycle testing." See this article for a thorough look at emissions and things related. |
Nice :bigtu:
I don't like coming back with cash; I usually will come back with beer and/or lunch. |
Originally Posted by Ben
(Post 169179)
Nice :bigtu:
I don't like coming back with cash; I usually will come back with beer and/or lunch. |
Yeah, any of the standard CDB's should be fine.
CDB = cheap domestic beer |
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