rx7_lover

Hi all,

im posting this after failing CA pre-smog test for the fifth time.

i think that my car is simply running too rich at any given loads/rpm. following facts lead me to think that the car is running rich... maybe way too rich.

1. poppings at lower rpm range (a series of pops)

2. smell of exhaust gas, and only gets about 11~13mpg city driving without getting on boost.

3. pre-smog test results. best result i got so far is... at 15mph, HC measured 143ppm where Max and Ave were 88/21 respectively. at 25mph, HC was 107ppm and 53/13. NO was a liitle high but it was much lower than Max.

one interesting point is that PowerFC showed better numbers than Stock ECU's. of course above numbers were obtained when i used PowerFC, even though PowerFC cut off the Airpump at around 2600rpm instead of 3000rpm.

followings were done...
-N-tech Highflow cat which has only less than 5000miles
-O2 replaced
-Oil changed
-Vacuum Hoses replaced and double checked for leaks
-air pump works properly
-injectors cleaned balanced at RCeng.

now im wondering if any of these parts,
-FPR (stock, but no leak)
-Fuel pump (stock)
-ACV
-N-tech HFcat failed prematurely

can anyone give some advice on how to tackle this problem?
any input will be appreciated.

Mr rx-7 tt

iTrader: (5)

Get someone who knows the power fc to lean it out.. but baby the car and do NOT boost it...also put 4 gallons of 93 in with a gallon or so of alchohol. (do a search as I am not sure of the mixture) also put a good stock cat on the car. (ask someone around you who has a spare to borrow it).

Mr rx-7 tt

iTrader: (5)

It sounds like your car isn't operating correctly as well...I would take it to a rotary shop in your area before you attempt the stuff I mentioned in the above post. Good luck.

rx7_lover

thanks Mr. rx-7 tt.

i already tried alcohol method without any success (ran richer for some reason).

i think there is problem with fuel system, and id like to find out what it is.

rx7_lover

i wonder if my problem has do with TPS setting?

i just read this thread...

https://www.rx7club.com/forum/showth...5&pagenumber=1

xthaboy17

I just passed 3 weeks ago, what i did was warm up my car for like 3 hrs, drove it like crasy, put 2 gallons alcohol u can get at home depot and my passed with flying colors. I used stock main cat though. so u might get different results. I also used stock ecu it actually gave me better numbers.

ttb

i heard if you can't afford to pass smog you can get a one time waiver.

Bryan_RX-7

i know this is off topic but i have looked every were for alcohol and could not find it. If you could give me a place where you get it and a brand name that would be great.

4g63

Yes, this is true, but I am not sure on the amount of repairs before you can get the waiver. I believe that if you have to spend more than $450 from a "Smog certified repair shop" that you can get a one time waiver.

rx7_lover

go to Home Depot Paint section, they are located where Paint Removers are. it is called 'denatured alcohol' and comes with blue/orange metal can.

rx7_lover

any more ideas on why the car is running too rich?

EGR, TPS, FPR...?

i can adjust fuel map thru PFC until i dont get poppings for smog, but id really like to find out what the original problem is.

RedX7

rx7_lover,
Let us know how it goes and what worked for you. I'm (hopefully) going to be moving back to SoCal in the next year, so I'm going to need all the help I can get in order to pass smog. Luckily, I only have to pass it once because I live waaaaay out in the desert. Good luck!

johnchabin

iTrader: (2)

You might find out what the penalty is before you mix alcohol with your gas, as this method is illegal. Make sure they don't impound your car (you are in California, the land of clean air fascists).

Besides, it's better to fix the problem of running too rich and losing power.

mjw

iTrader: (1)

How would they find this out in the first place? I've never heard of anyone testing the fuel that is in your tank.

FWIW I spoke with Nick at N-tech Engineering about his cat a while ago, I was curious how he could claim the cat flows 96% of a straight midpipe. He told me that cat has a straight through center section, if this is true it would not bode well for emissions at all. Maybe try swapping your OEM main cat back on and retesting?

j9fd3s

iTrader: (3)

double check that the acv is working, and that the rotor housings arent swapped front to rear. if they are it wont pass unless you put alcohol in the tank

mike

johnchabin

iTrader: (2)

Me neither. I just think it's important to know the consequences to help weigh risk vs. gain.

Kento

Two questions: how would a smog station determine that you were running alcohol in your fuel? There is no "approved" standardized test. It also might interest you to know that many refineries are currently adding ethanol to CA-bound fuel since MTBE and its derivatives were banned a year ago.
And under what authority would they have to "impound your car"? Smog stations aren't run by law enforcement officials.

johnchabin

iTrader: (2)

If you are comfortable braking the law without knowing the consequences, go ahead. I'm not.

Like I said, risk vs. gain. If there's no risk, then go for it.

Kento

Heh...



There! Nana na nah!

Perhaps it would be best to leave counseling someone on the finer details of passing emissions in a particular state to those who actually live there, rather than stating a rather obvious point that millions of Americans already know, and deal with anyway. $118 billion worth of aftermarket companies (the vast majority of which provide products that are technically "illegal" for road use) hope that we're able to assume at least some risk.

johnchabin

iTrader: (2)

One doesn't have to live in California to understand that your state has the strictest emission laws in the country.

My point is (as has always been) it would be wise to find out what the penalty is. It's clear to me that you don't know.

rx7_lover

thanks for sharing your idea, guys.

what would make the car run so rich in the first place? a peak injector duty never sees more than ~78% at 0.85bar(according to PFC). i think that number is too low but the car's still running very rich (HC number, poppings, 11~13MPG, etc)

another thing i found recently was that O2 readings at WOT read around 1.15~1.27 Volt (PFC).

Kento

Sorry, got sidetracked by paranoic mumblings of people who haven't even dealt with the CARB smog test...

Actually, it doesn't sound like your car is running terribly rich. You can pull back on your fuel maps, but the N-tech hi-flow allows a lot more HCs to escape anyway. And to tell you the truth, 11-13 mpg in stop-and-go city driving (even avoiding boost) isn't out of the realm of possibility for a modded FD. The PFC readings you've listed are from WOT throttle settings, which don't have any real bearing on the rpms that a CARB smog test on a rolling dyno will have your car running at.

I've spoken to a few FD owners who have had trouble passing smog with hi-flow cats, but some of them changed to the stock cat and passed with flying colors (using some denatured alcohol in the tank...) Do you have access to a stock main cat? What about a stock ECU?

Another factor I've seen is the station operator, and how he runs your car on the dyno. With a stock sequential setup, it's way too easy for many of these bonehead operators to dip into the boost when getting the car up to speed, and once you do that, you're done. The last place I took it to, the guy has done plenty of FDs, so he knew to carefully get on the throttle to get the rollers up to speed. Admittedly, I was using the stock ECU with a stock main cat (no precat), but I passed easily, and I didn't use any alcohol as a control measure just in case. I'd suggest trying to find a smog center whose operator will listen to your suggestions on how to run the car.

Also, if you haven't done it, it's a good idea to put in fresh plugs, even if they've only got a 1K or so miles on them. It makes a big difference.

ReodDai

This makes me feel very lucky that the only thing my work does exhaust related when inspecting is check the tailpipe to see if it has pressure (ex: cover the end with their hand). Only good thing about this hick town.

rx7_lover

Kento, thanks for the input.

my spark plugs are fairly new (~1500miles). oil and filters were changed prior to the pretest.

the reason of assuming the car is running rich is that whenever i give light load (throttle), it gets a series of poppings (like 5~10 of them). plus even on freeway crusing, i barely get 15~16MPG. my car is only lightly modded.

about the stock parts, i do have both stock ECU and main cat, but the main cat was cooked long time ago.

i can try again with two gallons of alcohol instead of one gallon. im sure i can find a way to pass smog, however, it is important issue for me to make sure the car is not running rich without any reason.

Kento

Back to the beginning, then....

Ask a PFC user who has similar mods on what their fuel cell settings are at that throttle/rpm position.