Passing Smog in an FD
#1
Passing Smog in an FD
Despite its poor emissions reputation, I think it is becoming clear from a variety of posts that I have seen over the past few years that a properly running FD will have no trouble passing. Quite a few people fail, obviously, but in general it seems to be due to some non functioning component (e.g., old O2 sensor, clogged cat, leaky injectors, non functioning air pump).
Here, for example, are my results from a recent CA emissions test. Car has 55k miles on original engine. All stock (for the test in any case) except for downpipe and RB exhaust. Used stock cat with unknown mileage.
Test________CO2%__O2%______HC(PPM)________CO%_____ ____NO(PPM)_____
______RPM_MEAS_MEAS_MAX_AVE_MEAS_MAX__AVE__MEAS_MA X_AVE__MEAS
15mph_1819_13.30__1.72_|_61__27__23___|_0.36__0.09 __0.02_|_493__157__106
25mph_2924_13.36__1.68_|_37__18__16___|_0.35__0.09 __0.04_|_516__161__104
Pretty clean. Be interested to see other people's numbers.
The slightly worrying thing is that the maximum allowable numbers have been dropping gradually for the past few years. I assumed that these were set at the time of a car's release.
Here, for example, are my results from a recent CA emissions test. Car has 55k miles on original engine. All stock (for the test in any case) except for downpipe and RB exhaust. Used stock cat with unknown mileage.
Test________CO2%__O2%______HC(PPM)________CO%_____ ____NO(PPM)_____
______RPM_MEAS_MEAS_MAX_AVE_MEAS_MAX__AVE__MEAS_MA X_AVE__MEAS
15mph_1819_13.30__1.72_|_61__27__23___|_0.36__0.09 __0.02_|_493__157__106
25mph_2924_13.36__1.68_|_37__18__16___|_0.35__0.09 __0.04_|_516__161__104
Pretty clean. Be interested to see other people's numbers.
The slightly worrying thing is that the maximum allowable numbers have been dropping gradually for the past few years. I assumed that these were set at the time of a car's release.
#5
Senior Member
iTrader: (7)
I don't know my tags were from like '08. Just took it to the shop to get a choppy idle and misc things worked out after putting it back together after a few years. I planned to just do a shady inspection somewhere, but while it was in the shop they just took care of that for me and figured out little things like passages turning into orifices and minute little things. Expertise that I would've never figured out.
#8
However, depending on how energetic the smog tech is, you may have a problem with the visual inspection.
My smog tech spent 5 minutes looking for mine before he called me over (the emissions diagram under the hood is very misleading wrt its location) and verified its presence with a mirror. Techs in previous years have simply not bothered to look for it.
#11
A N T I H E R O
iTrader: (19)
For the record, my car was from out of state with no EGR.
The intake and intercooler were returned back to stock, as was the original Catalytic converter. It did have a Downpipe and a PFS cat-back exhaust, however.
I had a hell of a time smogging an old Previa van in the past, but I learned from that experience. I added in one bottle of HEET (methyl alchohol) for good measure: Third Time’s the Charm | Grand Mighty
and just went for it. The main cat did its job and the car passed without issue, except that the NOx readings were a bit up there. I can't say how much of an impact the alcohol made, but this is proof that you can in fact pass California smog with no EGR and no pre-cat, provided everything else is working as they should.
The intake and intercooler were returned back to stock, as was the original Catalytic converter. It did have a Downpipe and a PFS cat-back exhaust, however.
I had a hell of a time smogging an old Previa van in the past, but I learned from that experience. I added in one bottle of HEET (methyl alchohol) for good measure: Third Time’s the Charm | Grand Mighty
and just went for it. The main cat did its job and the car passed without issue, except that the NOx readings were a bit up there. I can't say how much of an impact the alcohol made, but this is proof that you can in fact pass California smog with no EGR and no pre-cat, provided everything else is working as they should.
#12
Senior Member
iTrader: (3)
Join Date: Sep 2004
Location: CA
Posts: 258
Likes: 0
Received 0 Likes
on
0 Posts
Fortunately, the pre-cat has very little to do with the snif test. Apparently, it was included by Mazda to heat up quick and start knocking down the emissions sooner with warmup.
Good job on passing! A stock computer is also key...
Good job on passing! A stock computer is also key...
#15
I haven't had any problems passing CA smog, and I replaced the pre-cat with a DP. Otherwise the engine is stock and is well maintained. I do take it for a good warmup before I take it in for smog though.
#16
Recovering Miataholic
The NO numbers can be a problem with a disabled EGR.