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ICU vacuum/emissions test failure story 200 1987

posted by  someone claiming to be kswan on  Thu Sep 29 13:22 CST 2005 [RELATED]

So, recently I failed the Ca. emission test by being high on NO emissions. I scoured the boards discovered the fix for lowering NO by plugging the vacuum line to the ICU. After doing this my NO emissions were drastically reduced, but my HC and CO readings were so high that it was labelled a gross polluter.
Readings before were:
15mph HC (30), CO (0.01), and NO (1028)
25mph HC (29), CO (0.01), and NO (1139)

Readings after plugging the vacuum line were:
15mph HC (191), CO (7.47), and NO (160)
25mph HC (195), CO (7.26), and NO (177)

As can be seen I got exact opposite readings after plugging the vacuum line.
The only other thing done was the replacement of the headpipe/manifold gasket which was done by my mechanic who claims that the gasket wasn't that bad and it's replacement wouldn't have thrown things off that drastically.

Any help would be appreciated.

k.s.







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