what is good O2 voltage at WOT??
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Supreme Member
Joined: Jun 2001
Posts: 3,175
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From: Bedford, Tx
well the computer may ignore the O2 sensor. but it is still valuable for ME to determain how rich\lean i am running.. and .05 is VERY lean. rich is usualy above .5 so if i am supposed to be running rich.. and its only at .05 then im not..
i should also add that my BLMS are usualy above 128.. like upwards of 140-160.. which means when the computer locks it at 128 at WOT.. then im not going to be getting enough fuel anyways.. (hey im finally starting to learn this stuff!!)
i should also add that my BLMS are usualy above 128.. like upwards of 140-160.. which means when the computer locks it at 128 at WOT.. then im not going to be getting enough fuel anyways.. (hey im finally starting to learn this stuff!!)
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Joined: Apr 2001
Posts: 4,969
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From: USA
Car: yy wife, crazy.
Engine: 350, Vortecs, 650DP
Transmission: TH-350
Axle/Gears: 8.5", 3.42
This is in the "Tech Articles" on the homepage......
Thought you needed an expensive scanning device such as AutoXray or Diacom to view your O2 sensors voltage readings? Think again! You NEED to do this if you have an adjustable fuel pressure regulator or if you have a Q-jet equipped thirdgen and are changing the metering rods to achieve optimal performance.
You will need: A digital voltage meter, approximately ten feet of wire preferebly 12 gauge or smaller, wire connectors (Screw type "european" connectors preferebly), Jack, jackstand, wire strippers.
Step One: Disconnect negative battery cable
Step Two: Jack up vehicle on drivers side
Step three: Locate plastic connector for the O2 sensor near exhaust manifold, Disconnect.
Step four: Strip end of materials wire approx. 2 inches to expose core
Step five: Put exposed end into one end of the weather pack connector for the O2 sensor and reconnect.. Its a tight fit and you might have to trim or expose some more wire. It also might take a little force for it to snap backtogether.
Step six: Route wire away from exhaust manifolds or headers back into passenger compartment. If you plan on using this tuning aid temporarily simply route through door jamb. If not, there is a hole under the power booster in which you can route the wire.
Step Seven: Once inside of engine compartment trim wire to an accessable length. Connect wire to the positive probe of your Digital volt meter MAKING SURE that no part of the wire is exposed in any way so as to not ground the o2 sensor accidentally. European wire connectors worked well for me (the kind with a screw in each end to hold the wire in a plastic connector. Avail. at radio shack)
Step eight: Use the extra length of wire to make a ground for the Digital volt meter. Under the dash there are plenty of places to ground the wire. Connect it to the negative probe of the digital volt meter.
Step Nine: Lower car, reconnect battery. Start car and turn your Digital volt meter on.
The range is as follows 3mV being the leanest, 1V being the richest. Part throttle does not matter so much as the computer always keeps it somewhere in this range depending several on variables and inputs from other systems sensors. At Wide open throttle the MOST desireable voltage should USUALLY be somewhere between .850mV an .900mV Make adjustments accordingly to reach the desired settings. Remember, the lower the voltage the leaner, the higher the voltage the richer. This also has an effect on spark timing. For instance if your car was running lean prior to adjustment and you had the base timing set to just before knock you may be able to adjust your timing for more advance with more fuel. The same is true vice versa. In addition, if you have an old O2 sensor take this opportunity to replace it as an O2 sensors sensitivity greatly diminishes with increased mileage.
It is imperative that you DO NOT ground the O2 sensor wire. This will KILL your O2 sensor.
You will need: A digital voltage meter, approximately ten feet of wire preferebly 12 gauge or smaller, wire connectors (Screw type "european" connectors preferebly), Jack, jackstand, wire strippers.
Step One: Disconnect negative battery cable
Step Two: Jack up vehicle on drivers side
Step three: Locate plastic connector for the O2 sensor near exhaust manifold, Disconnect.
Step four: Strip end of materials wire approx. 2 inches to expose core
Step five: Put exposed end into one end of the weather pack connector for the O2 sensor and reconnect.. Its a tight fit and you might have to trim or expose some more wire. It also might take a little force for it to snap backtogether.
Step six: Route wire away from exhaust manifolds or headers back into passenger compartment. If you plan on using this tuning aid temporarily simply route through door jamb. If not, there is a hole under the power booster in which you can route the wire.
Step Seven: Once inside of engine compartment trim wire to an accessable length. Connect wire to the positive probe of your Digital volt meter MAKING SURE that no part of the wire is exposed in any way so as to not ground the o2 sensor accidentally. European wire connectors worked well for me (the kind with a screw in each end to hold the wire in a plastic connector. Avail. at radio shack)
Step eight: Use the extra length of wire to make a ground for the Digital volt meter. Under the dash there are plenty of places to ground the wire. Connect it to the negative probe of the digital volt meter.
Step Nine: Lower car, reconnect battery. Start car and turn your Digital volt meter on.
The range is as follows 3mV being the leanest, 1V being the richest. Part throttle does not matter so much as the computer always keeps it somewhere in this range depending several on variables and inputs from other systems sensors. At Wide open throttle the MOST desireable voltage should USUALLY be somewhere between .850mV an .900mV Make adjustments accordingly to reach the desired settings. Remember, the lower the voltage the leaner, the higher the voltage the richer. This also has an effect on spark timing. For instance if your car was running lean prior to adjustment and you had the base timing set to just before knock you may be able to adjust your timing for more advance with more fuel. The same is true vice versa. In addition, if you have an old O2 sensor take this opportunity to replace it as an O2 sensors sensitivity greatly diminishes with increased mileage.
It is imperative that you DO NOT ground the O2 sensor wire. This will KILL your O2 sensor.
Thread Starter
Supreme Member
Joined: Jun 2001
Posts: 3,175
Likes: 1
From: Bedford, Tx
wow. haven't seen that one before.. thanks.. but i should of added tht for the time being.. i am using A scan tool to get my readings. so its seeing what the computer is seeing.. but yes that highlighted info i very informative.. :hail:
now i just need an APFR
now i just need an APFR
Last edited by breathment; Oct 3, 2002 at 11:26 PM.
Supreme Member
Joined: Jan 2002
Posts: 1,162
Likes: 1
From: California
Car: Z28
Engine: L98
Transmission: T56
guys, guys, guys....
keep in mind that you can't tell AFR from a normal O2 sensor. Yes - 900mV is rich. But you don't know how rich. It could be 14.0:1 .... or 13.0:1.... or 12.0:1.... or 11.0:1... 900mV can mean ANY of those AFR's. and there is NO way to know (without some other more advanced sensor).
However...one thing is for certain. if you aren't getting > 500mV at WOT, then your AFR is at 14.7 or worse. that's about all you can say.
Regular O2 sensors can be summed up as follows:
if the O2 sensor is anywhere below 400mV, then you are leaner than 14.7:1. How much? Not possible to tell without a more advanced sensor. Could be 14.8:1 or 16.8:1.
If the o2 sensor is anywhere above 500mV, then you are richer than 14.7:1. How much? Not possible to tell without a more advanced sensor. Could be 14.6:1 or 10.6:1.
keep in mind that you can't tell AFR from a normal O2 sensor. Yes - 900mV is rich. But you don't know how rich. It could be 14.0:1 .... or 13.0:1.... or 12.0:1.... or 11.0:1... 900mV can mean ANY of those AFR's. and there is NO way to know (without some other more advanced sensor).
However...one thing is for certain. if you aren't getting > 500mV at WOT, then your AFR is at 14.7 or worse. that's about all you can say.
Regular O2 sensors can be summed up as follows:
if the O2 sensor is anywhere below 400mV, then you are leaner than 14.7:1. How much? Not possible to tell without a more advanced sensor. Could be 14.8:1 or 16.8:1.
If the o2 sensor is anywhere above 500mV, then you are richer than 14.7:1. How much? Not possible to tell without a more advanced sensor. Could be 14.6:1 or 10.6:1.
Supreme Member
Joined: Aug 1999
Posts: 2,441
Likes: 1
From: sweden
Car: GTA -89
Engine: Blown 415"
Transmission: 4L80E
Axle/Gears: Strange 12-bolt
check out http://w1.605.telia.com/~u60505093/index.htm
There you'll find software and links to build your own WB-O2 sensor and then you will be able to read correct A/F ratio....
/N.
There you'll find software and links to build your own WB-O2 sensor and then you will be able to read correct A/F ratio....
/N.
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