Xounlistedxox
Registered User
So, I took my 1989 sc 5 speed in for smog. It failed emissions.
I had fuel system cleaner in the gas, which probably didn't help. Also there was most likely some very old gas mixed in with the fresh gas.
Here's the read out @ 15.6mph target 15.0mph. Load hp 16.9 target 17.1
HC:
135 ppm actual, Max Allowed 106 ppm
NO(x):
1674 ppm actual, Max Allowed 762 ppm
CO:
.53% actual, Max .70%
CO2:
14.2%
O2:
.4%
P.E.F.:
.471
This car has been sitting for many years. I have put 13 gallons of fresh 91 octane gas in it and have driven it around for awhile to try to get the old gas out of it.
Typically high HC from my experience is a result of poor or failing catalytic converters. And nox is usually something to do with the egr system.
The car runs and drives good. I just changed the oil/filter, & fuel filter. There are no disconnected vacuum lines. I will be checking for leaks, or incorrectly routed lines.
The HC numbers are pretty close. Do you guys think this is something where if I give her a full tune up(plugs, wires, o2 sensors, fpr etc) it will pass? Or are the #'s too far off & I need new cats.
Update 1-20-14:
Since failing smog I have replaced with new parts Bosch o2 sensors, autolite double platinum plugs gapped @ .047", duralast plug wires all tested under 5k ohms resistance, & tested the egr valve at idle. The car dies as soon as I apply vacuum to the egr valve.
Update 1-23-14
Took it in for smog again. This time it passed everything except NO(x). I found that the egr vacuum solenoid was frozen and not allowing the egr to work. I'm hoping this will be enough for it to pass.
Update 1-31-14
Today I replaced the egr valve. Recently replaced the egr vacuum solenoid. The hose that connects between the egr tube & pfe sensor was broke off. This caused not only an exhaust leak before the o2 sensor, but also insufficient flow to the egr system. I replaced the pfe hose with a new high temp silicone hose as well. This took care of the code 33. Hoping this is all what caused such high nox.
Update 2-4-14
Took it in for smog again today. Same as last time, everything passed except nox. Even with a nearly completely new egr system the nox still failed.
Update 2-10-14
New Catalytic Converter Direct Fit Pipe arrived today:
Looks to be well made, and better flow than oem for sure. The resonator is wide and open inside. 5yr/50,000 mile warranty
Inside the resonator
Update 2-12-14
Passed smog today. The HC numbers were 0ppm @ idle, & 3ppm @2500rpm. The two stage idle test that the car actually needed didn't even screen for nox emissions, so I don't know if those were reduced at all, but considering the HC emissions pretty much disappeared completely I would venture to say the oem cats were either clogged, or bad. Either way the car runs a lot better with this new mid pipe in place. Definitely more power and running a lot more smooth.
Thank You all for your help and advice along the way I appreciate it very much.
I had fuel system cleaner in the gas, which probably didn't help. Also there was most likely some very old gas mixed in with the fresh gas.
Here's the read out @ 15.6mph target 15.0mph. Load hp 16.9 target 17.1
HC:
135 ppm actual, Max Allowed 106 ppm
NO(x):
1674 ppm actual, Max Allowed 762 ppm
CO:
.53% actual, Max .70%
CO2:
14.2%
O2:
.4%
P.E.F.:
.471
This car has been sitting for many years. I have put 13 gallons of fresh 91 octane gas in it and have driven it around for awhile to try to get the old gas out of it.
Typically high HC from my experience is a result of poor or failing catalytic converters. And nox is usually something to do with the egr system.
The car runs and drives good. I just changed the oil/filter, & fuel filter. There are no disconnected vacuum lines. I will be checking for leaks, or incorrectly routed lines.
The HC numbers are pretty close. Do you guys think this is something where if I give her a full tune up(plugs, wires, o2 sensors, fpr etc) it will pass? Or are the #'s too far off & I need new cats.
Update 1-20-14:
Since failing smog I have replaced with new parts Bosch o2 sensors, autolite double platinum plugs gapped @ .047", duralast plug wires all tested under 5k ohms resistance, & tested the egr valve at idle. The car dies as soon as I apply vacuum to the egr valve.
Update 1-23-14
Took it in for smog again. This time it passed everything except NO(x). I found that the egr vacuum solenoid was frozen and not allowing the egr to work. I'm hoping this will be enough for it to pass.
Update 1-31-14
Today I replaced the egr valve. Recently replaced the egr vacuum solenoid. The hose that connects between the egr tube & pfe sensor was broke off. This caused not only an exhaust leak before the o2 sensor, but also insufficient flow to the egr system. I replaced the pfe hose with a new high temp silicone hose as well. This took care of the code 33. Hoping this is all what caused such high nox.
Update 2-4-14
Took it in for smog again today. Same as last time, everything passed except nox. Even with a nearly completely new egr system the nox still failed.
Update 2-10-14
New Catalytic Converter Direct Fit Pipe arrived today:
Looks to be well made, and better flow than oem for sure. The resonator is wide and open inside. 5yr/50,000 mile warranty
Inside the resonator
Update 2-12-14
Passed smog today. The HC numbers were 0ppm @ idle, & 3ppm @2500rpm. The two stage idle test that the car actually needed didn't even screen for nox emissions, so I don't know if those were reduced at all, but considering the HC emissions pretty much disappeared completely I would venture to say the oem cats were either clogged, or bad. Either way the car runs a lot better with this new mid pipe in place. Definitely more power and running a lot more smooth.
Thank You all for your help and advice along the way I appreciate it very much.
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