280zwitha383 Posted October 1, 2006 Share Posted October 1, 2006 I thought I remebered someone saying you could roughly tell your a/f ratio with an 02 sensor and a multimeter (I would assume ohmmeter to measure the resistance). Is this possible or am I on something? Thanks Quote Link to comment Share on other sites More sharing options...
Clifton Posted October 1, 2006 Share Posted October 1, 2006 Measure the voltage. Narrow bands produce 0-1v, .45v is stoich. The higher the voltage the richer. Quote Link to comment Share on other sites More sharing options...
nismopick Posted October 1, 2006 Share Posted October 1, 2006 If you are measuring the a/f ratio at an exact rpm... sure (if your multimeter is that precise). But if you want to use it INSTEAD of an a/f gauge, it won't be able to keep up w/ the changing signal. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted October 1, 2006 Author Share Posted October 1, 2006 Hmm, I just want to get a clue.... Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 1, 2006 Share Posted October 1, 2006 Works better than you might expect. Shoot for .8V at WOT, get a QUALITY sensor. I used a one wire Bosch. Some people have had trouble with cheaper sensors. Quote Link to comment Share on other sites More sharing options...
Moridin Posted October 3, 2006 Share Posted October 3, 2006 I would say spend the money and get the wideband. How much is a few hundred bucks compared to a motor rebuild? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 3, 2006 Share Posted October 3, 2006 Unless its a very high strung engine, you're not likely to detonate a NA engine to death in a short period of time that it takes to get the thing in the ballpark. If it's turbo or supercharged or has 14:1 compression, then I agree, WB is the way to go. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted October 4, 2006 Share Posted October 4, 2006 Any one know if wide bands can be read with a multimeter? I have 2 widebands I pulled out of the wife's minivan when the heaters went out. The sensors still work, just open circuit heaters throwing error codes. I was thinking of installing an O2 just to help with tuning the carb. At $250 each I figured I might as well use the wide bands since I have them. I know the service manual says a dedicated "air fuel ratio sensor" tool must be used to trouble shoot them. Quote Link to comment Share on other sites More sharing options...
80LS1T Posted October 4, 2006 Share Posted October 4, 2006 The problem with using those "broken" sensors is that the heater is a very important part of getting an accurate A/F reading. If you did use them you would have to mount them very high up in the exhaust stream so that they would get hot enough to read correctly. Even then it might not be a 100% accurate. I dont think its even possible to use a single wire o2 to get accurate readings. It wasn't really intended to give that accurate of a reading and I wouldn't trust a 1 volt sensors to do the job of a 5 volt sensor. Again it has no heater so results might be less than ideal. It was really intended to rear rich or lean, not a specific value for rich or lean. Personally spending $400 on an LM-1 was worth it because I dont plan to ever stop working on cars and I can use it over and over. Plus I can get some of that back when buddies with out one want to use it or have me use it because I can charge them a small fee for wear and tear on the sensor since it will eventually wear out. Guy Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 4, 2006 Share Posted October 4, 2006 I'm not going to make the whole argument AGAIN, but if you search you'll probably find old threads where I had friends compare their NB to WB on the dyno and they were RIGHT ON. Not the best for the really high strung engine that has to run exactly perfect to prevent it from exploding, but a hell of a lot better than what most carbed NA guys do, which is read plugs (badly). Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted October 5, 2006 Author Share Posted October 5, 2006 Well if it can be done with $30 instead of $400, who's better off? What brand O2 sensor did you use J. and for what vehicle? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 5, 2006 Share Posted October 5, 2006 It was a one wire Bosch sensor off of a mid 90s GM V6 FWD car. A friend of mine used the heated Bosch sensor too (not sure what app), both worked well. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted October 5, 2006 Author Share Posted October 5, 2006 How much did it cost you? And do you think that's the best one to use? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 5, 2006 Share Posted October 5, 2006 I had good luck with Bosch, as did a couple friends of mine. One used a heated O2, but like I said, just takes a couple minutes and then it reads fine. I think it cost me about $35 for the sensor, and then I seem to remember $6 for the voltmeter. Prices may be up a bit, I think I bought that sensor more than 5 years ago... Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted October 5, 2006 Author Share Posted October 5, 2006 Well here's another question that just hit me seeing as you only paid $6 for your meter it must have been an analog one. Is that better since it's seemingly more realtime than a digital one? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 5, 2006 Share Posted October 5, 2006 Actually it was a digital. I looked for an analog and couldn't find one anywhere. That means that you have to deal with the refresh rate on the display, but if you do a whole bunch of pulls you'll get it right. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted October 5, 2006 Share Posted October 5, 2006 I think an analog MM will load down the sensor too much. Pretty sure you have to have the high input impedance of a digital MM to read the weak signal from an 02 sensor. Well I already have the MM and the wideband O2, so if I ever get the motor running I guess I will find out what works. All it will cost me is a mounting bung. Quote Link to comment Share on other sites More sharing options...
280zwitha383 Posted October 6, 2006 Author Share Posted October 6, 2006 Thanks for the info! Quote Link to comment Share on other sites More sharing options...
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