Failed Emissions. sonfoa...........
The car has new
opti
plugs
wires
oil and filter
cleaned stock injectors
the car DOES have a cat.
I have tried 93 octane and 87 octane and got almost identical results.
results..
HC PPM
Readings - low 108 high 71
allowed- low 220 high 220
pass
CO%
readings - low 1.94 high 2.51
allowed - low 1.20 high 1.20
FAIL
RPM READING
readings - low 1254 high 2532
limits- low 500 high 2200
PASS
help.... me...
You could also look into PCV, air filter, and O2 sensor if they havent been changed in a while.
I would also check fuel filter, MAP sensor, and MAF sensor.
Last edited by LT1; Feb 16, 2012 at 07:33 PM.
There are four main things that could cause it. Oxygen sensors, MAP sensor, Throttle position sensor(TPS) and the coolant temp sensor. (ECT) If you have a manual there is a procedure for checking the ECT at a certain temp and a procedure for checking the TPS. If you can't find it let me know and I'll scan it for you. My books are for a 1995 but they'll work just fine.
You could also download Freescan and get an ALDL cable and check all your sensor readings into the ECM.
Sorry I can't be of much more help but your gonna have to get into this one a little bit or just start throwing parts at it.
Last edited by 1963SS; Feb 16, 2012 at 08:57 PM.
I dont have time to order the aldl cable and go through that. I need this thing fixed or rigged to pass by the 27th. Do the CO numbers look WAY off or just a tad? those numbers are all chinese to me.
Usually it's not the MAP sensor. It's pretty robust and holds up well. The ECT is know to cause a problem. Are you any good with a multimeter? If not are any of your friends? If so we can fairly easily check the TPS and the ECT. That would leave the best guess as the Oxygen sensors. We should rule out the ECT and TPS first though.
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Is the PCM tuned with lower fan on temps?
What temp is the engine reading on the gauge when the test is done?
I agree it's rich but why?
What has changed since the last time it passed?
is the cat located close to the mid pipes? Is there an exhaust leak?
How old are the O2's
Are the fans always on?
Smog air valves all working? Pump?
I'd do that or have someone spray shop air into the cat during the test when I was to lazy to figure out why a car wouldn't pass. It has to be after the primary O2s though. I might have a small leak at the header gasket. could that be fudging me up? And the kid that had the car before me de-screened the MAF.
Do you notice if the car seems to run richer after it warms up and goes closed-loop, or does it stay constant? Sometimes it can be hard to tell, but if it seems like it's running richer after it's warmed up, it almost definitely is the O2s, if it's really rich even when cold, it could be any of the items that 1963SS mentioned.
I feel your pain - it's no fun failing smog - my truck has 314k+ miles on it and most of the motor is original, so you can imagine the fun I have had getting that thing to pass the past couple of times. I do the "alcohol trick" to help with my truck, but that won't help in your case - that typically only lowers the HC levels and won't do much for CO...
Good luck!








