shl76

i failed smog in CA with a 93 prelude vtec with aem cai, greddy header and greddy exhaust with carsound/magnaflow cat (2.5").

carsound cat is 3k miles old (my suspicion is the cat, may need to get an OEM cat).

CAR RUNS EXTREMELY WELL WITH NO PROBLEMS!!!!

JUST DID THE FOLLOWING B4 GOING TO GET TESTED:
a) changed oil (Mobil 1)
b) changed O2 sensor (denso)
c) changed spark plugs (NGK)
d) cleaned out EGR ports and EGR itself of the carbon build up
e) timing is at 15 BTDC
f) ran G2P
g) dizzy is less than 5k miles old (king distributors)
h) coolant has been flushed last year
i) valves adjusted 4k miles ago
h) drove for 45 minutes

here are my numbers (please note how i not only fail all three at 15mph but how HC and NOx drop by a lot at 25mph to well below passing levels):

15mph
CO2 --> 14.01
O2 --> 0.44
hc --> 157 meas, max is 88 --> FAIL
co --> .58 meas, max is .52 --> FAIL
nox --> 1946 meas, max is 704 --> FAIL

25mph
CO2 --> 14.60
O2 --> 0.05
hc --> 53 meas, max is 53 --> PASS
co --> .05 meas, max is .50 --> PASS
nox --> 142 meas, max is 738 --> PASS

as you can see, my numbers pass at 25mph but fail at 15mph.

my guess for the culprit is the carsound catalytic converter which is less than 3k miles old... but i hear mixed reviews on these passing smog.

is my best going with a oem cat?

TIA!

Prudz_lude

iTrader: (1)

ummmm you expected to pass with a high flow cat?

Chris F

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Prudz_lude &raquo;</TD></TR><TR><TD CLASS="quote">ummmm you expected to pass with a high flow cat?</TD></TR></TABLE>

I have in the past, especially with a newer one, and failed with an older one. My emissions test was probably easier though, no treadmill. Nonetheless..

If HC is too high (too rich), CO is too high (too rich), NOx is too high (too lean/hot?)... ummmm... yeah, either your cat is cold or it's just not working well.

-Chris

5thgenbb6

u should probly get an oem cat to swap in for tests then swap the carsound back in for driving

no1knows908

Its a possibility that the catalytic converter may not be heating up enough at 15mph to correctly clean the exhaust. The factory converter created more back pressure but also held in more heat. Try running it pretty hard before the test to heat up the converter.

MrLude1

Try a bottle or two of heat w/the highest grade fuel available. Then do some city driving for a couple of hours...worked for me.

97Preludeguy

I've heard of people heat wrapping their cats to make them heat up both more quickly and to a higher temp...Never tried it myself though...Just putting it out there