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Need to pass emission test

Forum: C4 Engines, Driveline and Handling

3 Messages
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Need to pass emission test

Posted: 5/17/14 7:45amMessage 1 of 3
l
ljcme
Free Member
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Joined: 5/17/2014
Posts: 1
90 L98 90000 miles

I recently replaced my intake manifold gasket due to a leak at the rear wall.  Took my time and did a lot of cleaning at re-assy. Now I cant pass my emission test and it is hard starting (4 or 5 tries) when cold.

CO is 8.0 should be 1.2 max
HC is 350 and should be 220 max

I have rechecked for vacuum leaks and cant find any, PCV seems to be working well.

Any ideas where to look?

Thanks
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Re: Need to pass emission test

Posted: 5/17/14 2:51pmMessage 2 of 3
d
davep85c4
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Joined: 4/4/2009
Posts: 254
ljcme said:
Any ideas where to look?

Thanks


 Be sure the MAP is connected to vacuum, and that the electrical connections on the MAP are tight and secure.
CO=8.0 is uber-rich. No vacuum to map or high MAP signal will cause this.



|UPDATED|5/17/2014 2:51:21 PM (AZT)|/UPDATED|
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Re: Need to pass emission test

Posted: 5/18/14 11:59amMessage 3 of 3
B
Big Mike 49
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San Jose, CA - USA
Joined: 5/10/2012
Posts: 81
Vette(s): 1988 Corvette / Blue Pearl

Oil Change ( used engine oil carries high amounts of Hydrocarbons ) New air filter , Check your timing also , I had issues this past year on mine & once I did these things  all the bad stuff was reduced & I pass with flying colors . I believe stock timing is set about  4 deg, ATDC.  I kicked mine down to 2 deg.



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in Forum: C4 Engines, Driveline and Handling


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