93 Series 80 failed high speed CO on NV smog. What should I look for?
fail high speed CO (1 Viewer)
- Thread starter Jaycontractor
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So did you have to smog on a dyno? Down here in Vegas its just a tailpipe test running at 2500 rpms in park. Seems like you are rich. Post your smog sheet so we can see the numbers.
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Tailpipe at 2,500 rpm, passed idle test, but was at 1.38 % for CO. It’s running rich at high rpm. Checked MAF and cleaned, wasn’t bad. Checked throttle position sensor (TPS) was loose and one screw stripped. I’m going to replace and fix screw. Is there and easy way to set TPS correctly?
Might check here for info. Not sure if 93 and 96 are the same though.
Admittedly having only read up on it here, you need a gap gauge set on the order of 0.005 - 0.0005..
Give or take a decimal point.
So if you have that, yes.
You could use scan gauge if ya had obd 2, since you don’t follow fsm and get multimeter it is pretty easy, you can prob put the new one where the old position is and be close. I do not think new tps will change much though
Rich conditions could be due to something in the ignition system plugs, wires, cap rotor etc. Also when was the last time were the O2 sensors replaced?
Read somewhere that higher octane fuel could be an issue for motors designed to run lower octane fuel, do not know if there is any truth to that though.
If you continue to fail, then I would look at replacing the cats and you might also want to look into denatured alcohol for a quick fix to pass emissions. Then you have a year or whatever it is till you have to register again in NV to fix the issues while maintaining the driveability of the LC.
Read somewhere that higher octane fuel could be an issue for motors designed to run lower octane fuel, do not know if there is any truth to that though.
If you continue to fail, then I would look at replacing the cats and you might also want to look into denatured alcohol for a quick fix to pass emissions. Then you have a year or whatever it is till you have to register again in NV to fix the issues while maintaining the driveability of the LC.
effjay80
SILVER Star
My understanding always has been that running higher octane *MAY* help lower NOx at the price of increasing CO and HC. And yes my Toyota Sensei advised me that the MCU in my 94 has parameters set to run regular most efficiently and run that for my tests.
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smritte
SILVER Star
We use to do that on the old carb vehicles to get them to pass CO. Worked great.
