So I have failed CA smog twice now where before I would pass with flying colors with the same mods.

I actually took most of my mods off just to pass and have just on this stuff:
HKS downpipe
Apex catback (not that it matters)
Stock airbox
Stock main cat
Stock ECU

I just installed new plugs, new wires, new O2 sensor, and changed oil but still failed the second time.

Here are the values:

15 mph:
HC: Max - 61, Meas - 240
CO%: Max 0.36, Meas 0.45

25 mph:
HC: Max - 493, Meas - 98
CO%: Max - 516, Meas - 167

And I got these values after driving on the freeway for an hour. I'm thinking I have a vacuum leak somewhere that I can't pinpoint. I've tried the carb cleaner spray trick with nothing found. The car has only ~68,500 miles on it and has passed before with no problem.

Should I just resort to the denatured alcohol trick to get past this hurdle?

Thanks in advance for any opinions.

 

do you have an airpump ? do you have a pfc ? hopefully you have both. high HC and CO means you are running rich. i had to lean my car out to pass NJ state emissions testing

 

denatured alcohol is isopropyl alcohol which has a lot of water. Try methanol. Ask the test station to do a training run so you're not labeled as a gross polluter.

 

Yes, I am running an airpump. I do have a PFC, but I replaced it with the stock ECU since I thought I would fail due to a check engine light due to the PFC. Am I mistaken? I am also unfamiliar with tuning on the PFC, but I suppose I could get familiar.

What gets you labeled as a gross polluter - failing smog a set number of times? I told the test only station to just run a pre-test and he said that they are still required to send results to DMV even if just a pre-test.

As for denatured alcohol vs methanol, what is the ratio for methanol and where is it available for purchase?

Thanks everyone.

 

Did the test measure at idle?

 

I don't think so, just a 15mph and 25mph dyno run. Also, I just checked and my air pump appears to be working. The pulley face is freely spinning, no squeaking sounds, and disconnecting it changed my idle a bit.

How do I go about checking the ACV?

 

can you post up the complete measurements including the 02 readings? 02 readings are pretty important indicator to tell why HC and CO are high.

-AzEKnightz

 

i'd do a steam clean as well... plus it'll let you know if you have any exhaust leaks too..

 

Sure thing.

15 MPH:

RPM measure: 1720
%CO2 measure: 14.1
%O2 measure: 0.7

HC (PPM)
Max: 61
Meas: 240

CO (%)
Max: 0.36
Meas: 0.45

NO (PPM)
Max: 493
Meas: 98

25 MPH:

RPM Meas: 2761
%CO2 Meas: 14.1
%O2 Meas: 1.0

HC (PPM)
Max: 37
Meas: 33

CO (%)
Max: 0.35
Meas: 0.02

NO (PPM)
Max: 516
Meas: 167

It's the 15mph part where I fail.

 

Hm, odd results. Our '94 FD's 2010 CA smog test result is here; perhaps your coolant temperature sensor is open or at least out of spec, which would cause rich running at fully warm engine temperature. Have you pulled PCME fault codes to see if you have any stored faults? A coolant temperature sensor fault would be #9.

BTW, it's also odd that the MAX values for HC and CO are different between my 2010 test (Orange County) and your test (San Diego County).

 

Drop the HKS downpipe and put stock precat back . Also possible that your old cat is gone. weld in new 200 dollar aftermarket one and drive 20 miles before test. Do not shut car off and let them test. But since you are to the third test ask for training run so you're not labeled as a gross polluterthe Like pomanferrari Said.

 

I'll pull the codes later today. When you say coolant temperature sensor, are you talking about what the FSM calls the water thermosensor?

I find it hard to believe that I'm failing because of the DP, since I've passed with it on before, but maybe I might have to get a precat and throw it on. Too bad I got rid of the one I had.

 

OK, so I pulled the PCME fault codes today and the only code it threw was a #38 to me (unless I'm mistaken and it's actually a #28), which is just the accelerated warmup system. I'd expect that since I blocked that off and disconnected the wire for it on the UIM.

So any other ideas, folks?

 

in the pfc you can easily adjust it temporarily with the commander using pim voltage for the rpm range the tests are in

 

Looks like it's not in O2 feedback operation for the 15mph test; the RPM's are a little low (which might prevent it from going closed loop)....it also might help to get it closer to 2,000, a speed which is known to work.

 

Once the car is warmed up, it will be in close loop. However if I remembered correctly, at 15mph, you can only go up to around 1500-1800 rpm.

My question is, how old is your cat? I am sure if your cat is running correctly (the hotter the cat, the better it is at burning off excessive HC and COs.)

I guess is that your cat is starting to turn bad but would be ok at higher rpm/higher heat range.

IF you can lean it out more at lower rpm for the 15mph test you should be able to pass the test. BUT if it doesnt work, I suggest a new cat.

-AzEKnightz

 

Yes. It's the upper one (with green connector) in this picture.