CaptainZilog Posted February 14, 2004 Report Share Posted February 14, 2004 Hello, a friend of mine has a 89 Cutlass Supreme, and is having a bit of a problem passing emissions. My question is this, is there a good way to diagnose the EVAP system? He's getting a code 45 (O2 sensor fail, rich) and we just ran his O2 on an oscilloscope, and the thing is almost constantly above 1V output, and spiked to 2+V a number of times. He just finished testing his injectors and they all read properly, and he just replaced his MAP sensor, so next target is the EVAP. Any help is appreciated. Thanks. Quote Link to comment Share on other sites More sharing options...
Scannerman Posted February 14, 2004 Report Share Posted February 14, 2004 welcome Quote Link to comment Share on other sites More sharing options...
Robby1870 Posted February 14, 2004 Report Share Posted February 14, 2004 Hello, a friend of mine has a 89 Cutlass Supreme, and is having a bit of a problem passing emissions. My question is this, is there a good way to diagnose the EVAP system? He's getting a code 45 (O2 sensor fail, rich) and we just ran his O2 on an oscilloscope, and the thing is almost constantly above 1V output, and spiked to 2+V a number of times. He just finished testing his injectors and they all read properly, and he just replaced his MAP sensor, so next target is the EVAP. Any help is appreciated. Thanks. Theres your problem. The 02 voltage should constantly fluctuate, hardly every staying constant. Quote Link to comment Share on other sites More sharing options...
CaptainZilog Posted February 14, 2004 Author Report Share Posted February 14, 2004 Hi, thanks for the welcome. His O2 is brand new, probably less than 2 months old. Maybe it's been contaminated already, but that still means there is another problem somewhere. We're thinking if it isn't the EVAP, then the ECM is gone. Thanks. Quote Link to comment Share on other sites More sharing options...
Intlcutlass Posted February 16, 2004 Report Share Posted February 16, 2004 If your cat is bad, it will cause early failure of the o2..... Something to check.... Quote Link to comment Share on other sites More sharing options...
SleeperRed90TGp Posted February 16, 2004 Report Share Posted February 16, 2004 You should never see more than .9 volts from the O2 which is pretty rich. Sounds like your voltmeter won't read tenths of a volt. Try your meter on another car. Try your O2 on another car. What failed? HC (PPM) I'll bet. Just went through that BS. If so it could be as simple as a vacuume leak on the MAP sensor or the fuel regulator. Jud Quote Link to comment Share on other sites More sharing options...
89oldscutlass Posted February 16, 2004 Report Share Posted February 16, 2004 Welcome to w-body. Another 89 Cutlass owner cool deal. Quote Link to comment Share on other sites More sharing options...
CaptainZilog Posted February 17, 2004 Author Report Share Posted February 17, 2004 Wierd, I posted a reply a few hours ago and it seems to have disappeared. Anyhow, he replaced the ECM today and the car relearned its operating conditions. The exhaust odor was a lot better than before. Hopefully it was just that although he has a backup set of cylinder heads just in case. A few things, he does have new cats. And new MAP, O2, ACT, vacuum lines, ECT, etc, etc. I think the only old part is this stupid ECM. The O2 readouts we got were actually from a digital oscilloscope, a guy I do some work for is a contractor that goes out and measures the fluctuations in giant industrial motors to see if they need maintenence. I highly doubt it was inaccurate. He failed both HC and CO (in my state it's both in grams/mile). Quote Link to comment Share on other sites More sharing options...
Nick1234 Posted February 17, 2004 Report Share Posted February 17, 2004 i just went for my emmisions test last wednesday and passed. i went in thinking i was going to fail so i took 1/4 tank of gas, and to bottles of Iso-heat, and then beat the hell outta the car on the way there. I thought i was going to fail cause two years ago, i barely passed, and my cat has gotten worse, and now rattles constantly. made it though. when i got there, it was so hot, when you gave it a little gas, it rattled so bad, i was supprised that i passed. He should also make sure he has a clean throttle body, iac, air filter, and the tire pressure is where it belongs. nick Quote Link to comment Share on other sites More sharing options...
CaptainZilog Posted February 17, 2004 Author Report Share Posted February 17, 2004 Grr, FAIL HC : 0.8 std 1.76 read CO : 15.0 std 21.2 read Where exactly is the evaporative canister on these things? Thanks. Quote Link to comment Share on other sites More sharing options...
89oldscutlass Posted February 18, 2004 Report Share Posted February 18, 2004 Im glad we dont have those emmisions test here where I live. Hell all they would have to do is look up at the ozone dissapearing above my cars as I drove by. Quote Link to comment Share on other sites More sharing options...
jamcneely Posted February 20, 2004 Report Share Posted February 20, 2004 What does Tire Pressure have to do with a screwed O2 sensor? Quote Link to comment Share on other sites More sharing options...
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