Help on emissions on '94 Z28!

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Jun 21, 2008 | 05:35 PM

Optikslobb

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From: Georgia

Help on emissions on '94 Z28!

Ok, took it in for emissions test today and got back some really bad readings...not sure whats wrong. Anyone got any ideas?

(reading)/(allowed)

25/25 test
HC ppm = 1652/114
CO% = 1.11/0.63
NO ppm = 1795/796

50/15 test
HC ppm = 1184/117
CO% = 0.91/0.65
NO ppm = 1482/879

I have no idea and really need some help here, I got to get this thing on the road.

Jun 21, 2008 | 08:20 PM

taeketsu

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My LT1 failed HC and CO about 2 weeks ago. What I'm doing is trying that "CRC Guranteed to Pass" Emissions formula (look it up), and if that doesn't pass me on the retest I'm gonna try seafoam.

And if that doesn't work then I'm pretty much screwed, but you should try the 2 options I gave since they're cheap and (usually) help people.

Jun 22, 2008 | 10:51 AM

95ZRagtop6M

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From: NJ

The first thing I would check and/or replace are the O2 sensors and spark plugs.

Jun 22, 2008 | 11:03 AM

BizZzatch350

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From: T E X A S

I failed on those, my car had a burned plug wire. Find out what the problem is.

Jun 22, 2008 | 12:42 PM

nomoneyz

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From: Apple Valley - So Cal

This was a major problem with my sisters z. We did a full tune up and tried that guaranteed to pass stuff and still failed. It came close but wouldn't pass. Ended up having to get a "special smog".

Jun 22, 2008 | 09:14 PM

Optikslobb

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From: Georgia

Thanks for the input. I just did a full tuneup around 2 months ago, but I know how opti's can be so I am considering it. I am not throwing any codes though, so that is why I didn't really think it was the O2 sensors.

Jun 23, 2008 | 07:56 PM

petechapter50

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better igniton would help with the hydrocarbons. soo like bigger wires msd coil, box better plug....and idk about the mds opti....iev herd mixed reviews