failled smog w/ mods

[james85z28]

this is the dyno-roller test in CA but the advice is not limited to CA.

results: I failled all the emmisions test.

HC 15 MPH 25 MPH
max: 126 101
meas: 139 128

CO
max: .79 .59
meas: 1.07 1.16

NO
max: 1118 978
meas: 1490 1259

what could cause each of those conditions to fail?

According from my scanning data I should be running lean, BLM 131. I have a 180* stat installed with the fanson/off at 217/212. My 3" cat is less than 1 year old and I installed a new O2 sensor. My compression is about 10.1:1 with my aluminum heads. My combo isn't radical at all. I have a zz4 cam, accel base/runners, K&Ns, 3" converter and cat-back, and the edl heads.

any suggestions?

[WS6 VERT]

HC is unburnt gas. Either your not getting complete combustion, or your converter isn't working right. Do you have an MSD?

Is your EGR valve working?

You may need to let your car get up to the 220°, that may help. You could also try some of that additive that "garuntee's" you'll pass the sniffer :rolleyes:

[LL6]

Your air line to the cat is still hooked up, right?

[james85z28]

yep all my smog stuff is hooked up - EGR, air line. I do have an MSD. The EGR valve is <1 yr. old and is a new GM/delco part. My fan on/off temps are 217/212. I have the GTP stuff but thought I wouldn't need it because everything is new: EGR, CAT, injectors.

I'll put in a 195* thermostat, change plugs, see what other things people say, drop in some GTP, pray, and sacrifice a few small animals.

My compression is about 10.0~10.2:1 . My scann data says I am on the lean side, BLM 131, so I'm afraid to go too lean with my high compression and cause the higher NO.

hmmm.

[WS6 VERT]

Your only really lean/rich in Open Loop. The fact that your BLM is 131 means that the ECM added fuel to keep you stoich, so really, your not lean, providing you are in Closed Loop.

Anyhow, adding fuel would increase your CO

[james85z28]

I thought
BLM >128 = lean
BLM <128 = rich

[WS6 VERT]

It does, it means you were rich/lean. However, the fact that the ECM compensated, means you are stoich. That just means that if you were in Open loop, you would be rich/lean. In closed loop, the ECM compensates for the variations, and shows the changes made in BLM/INT values.

[james85z28]

My bad B,

I am running lean SO my car is adding fuel to get the right mixture. I'm a little slow today. I was going to by the Baer brakes if I passed smog OK, I guess the brakes will have to wait.

[WS6 VERT]

Yeah, basicly. That sucks you'll have to put money into for the sake of passing smog. :(

[Michael]

Have the same problem as you James. Even though I don't have to get sniffer test I have a BLM above 128 and am running rich but puter is saying I am running lean. Maybe once I tune the chip it will be okay.

Otherwise I can't figue it out. I have all the air stuff hooked up but got rid of it last week, am putting on headers so all that crap went off.

[LL6]

James, a couple of thoughts, and BT please chime in...

Custom chip tuning problems, ie. spark advance, etc? Static timing. What condition is the engine in, new heads on old shortblock..? If that is the case, what is the effect of oil in the combustion chamber on emissions? PCV valve inop. Could plain old blow-by cause this?

[WS6 VERT]

Burning oil will definatly cause trouble w/ the emissions, but I'm not sure he's burning oil.

Yeah, you don't really need a custom chip to adjust timing, just turn the ol' distributer. However, I don't know if adding timing, or taking timing away will help.

[Pantera61]

I know that you said that everything is hooked up, but when you changed your cam did you blow out the pcv hoses? When the egr was changed? I had a friend that couldn't pass and we took it a shop and that is all they did, clean everything up and then it passed. In fact, it passed even lower than we thought. jm2cents

[AusRs]

glad we dont have that stuff in aus as yet however my car with NO air and gutted cat with an aftermarket ecm STILL passes the aus standards smile.gif smile.gif smile.gif
and IF we ever get visual inspections ...bet no one in aus dot knows what a camaro has to have smile.gif graemlins/hump.gif

[james85z28]

the engine, heads, intake EGR, PCV, injectors, vacuum lines, etc. are new. I replaced them last summer.

I have the roller TBI cam that came with my caprice replacement 350. If it comes down to it I'll install that cam. I don't think the ZZ4 is very clean at the 1500 TPM they are testing me at, both at 25MOPH@1500RPM and at 25MPH@1500RPM.

[james85z28]

passed with flying colors.

while I replaced my intake gasket last weekend it was evident by the clean passages that my EGR wasn't working-- and while I w removed my plenum I saw that my EGR vacuum line was smashed between it and my fuel rail while the vaccum line was broken and creating a leak.

But the main reason I failed was because my cat was hollow. I guess I hit it on too many speed bumps or driveway apexes and spit it out the exhaust, which would explain why I thought my flowmaster was way too loud and noisy inside the car.

I beat all the averages by more than half on our dyno run smog checks. clean. CO% was .01 (max= .79, ave=.18). HC (PPM) was 30 (max=126, ave=126). NO (PPM) was 126 (max=1118, ave=394).

feeling a lot better now. Now I need to see about them baer brakes.

[WS6 VERT]

Originally posted by NOTaGTA:
HC is unburnt gas. Either your not getting complete combustion, or your converter isn't working right. Do you have an MSD?

Is your EGR valve working?

Geeze, don't wanna say "told ya so!" tongue.gif

Thats awesome that you got it all fixed. I hope the needed parts didn't empty out all your mod money :D

[james85z28]

you just did ;)

My mod money is going into the non-performance stuff for now - window weatherstrip, door seals, hinges (new design maybe), carpet, other upholstry, then my front brake upgrade.

I have some CRX seats for my mustang that I like, so I'll see if I can find a another good set and have them re-upholstered in the stock camaro threads. Those seats are like recaro's. A bench seat in a camaro couldn't offer less lateral support than our stock POS designs.