Wideband sensor after the cat

[JeremyH]

Don't a lot of tuners use sniffers clipped on the end of the line to tune with?

Some "tooners" do. Just reiterates the fact that good tuners are harder to find.

I personaly wouldnt let anyone near my car to tune it with a tailpipe sniffer.

 

[white05gt]

No sensor/gauge combo that is only a couple of hundred bucks is that accurate anyway.

This pretty much sums up my opinion of this topic and I think Bruce has the same view on this also. The difference in readings Jeremy pointed out when comparing a dyno wideband readings to the setup installed on the car can be related to multiple things. For instance, quality of the wideband, how long since wideband has been calibrated, placement and other variables.

 

[Fullboogie]

Help me out here - it is my understanding that the LSU 4.2 sensor (used on most widebands today) has pretty darn accurate resolution, less than .1 off from the Horiba sensors. So why the comments on the "cheap" $200 gauges? These are the first comments I've ever seen questioning their accuracy.

 

[TexasBlownV8]

I would think the 'cheak $200 gauges' dont even use wideband signals, or if they do, anyone in their right mind should know what POS they're buying.

The accuracy of the sensor can only be relative to its position and exposure to gases in the exhaust stream, and to the composition of those gases. And then also to the controller/sensor/gauge setup driving and using it. You use 10% tolerance roughly-close components, your accuracy will be off.

Besides, it is mainly WOT we're interested in, whereas PT the PCM has much more of a variability in the readings by the way its changing the a/f all the type. And we usually use the w/b reading as a general reading anyway, as to what our system is doing, so we're not running lean.

Those tooners who use tailpipe sniffers can do so accurately IF and only if they know precisely how off they are in reading the exhaust in that particular vehicle. The good tuners will use their own sensor/setup in the proper place. My tuner prefers to remove one of my wideband sensors and use his, until he's verified that mine are just as accurate.

 

[JeremyH]

I would think the 'cheak $200 gauges' dont even use wideband signals, or if they do, anyone in their right mind should know what POS they're buying.

The accuracy of the sensor can only be relative to its position and exposure to gases in the exhaust stream, and to the composition of those gases. And then also to the controller/sensor/gauge setup driving and using it. You use 10% tolerance roughly-close components, your accuracy will be off.

Besides, it is mainly WOT we're interested in, whereas PT the PCM has much more of a variability in the readings by the way its changing the a/f all the type. And we usually use the w/b reading as a general reading anyway, as to what our system is doing, so we're not running lean.

Those tooners who use tailpipe sniffers can do so accurately IF and only if they know precisely how off they are in reading the exhaust in that particular vehicle. The good tuners will use their own sensor/setup in the proper place. My tuner prefers to remove one of my wideband sensors and use his, until he's verified that mine are just as accurate.

 

[rayS197]

So if a customer brings his vehicle to be tuned and the customer does not have a wideband sensor , how do the "tooners" proceed?
1. Turn the customer away as there is no wideband to obtain an accurate reading?
2. Remove an 02 sensor and install a wideband sensor of his own.
3. hook up the tail pipe sniffer, watch different parameters while on the dyno and adjust the tune based on his experience as a "tooner"?

Im just asking.