WB O2 Datamaster Question

[QUIKSUV]

My DIY WB O2 is up and running and seems to be working fine. I modified the bin with Dig's WB code and can see the AFR in Datamaster as advertised. I did notice the commanded EGR Duty Cycle in Datamaster moves in relation to the WB AFR. It never reads 0 unless the WB is disconnected. I have the EGR turned off so it is not a big concern. Just wondering if this was normal or if I made a mistake entering the WB code? No problems with Datamaster with a std chip.

 

[Typhoon #1133]

Mine has been doing the same thing. I talked to a few people about it and they where not sure why it was doing it, and said it really doesnt matter.

 

[leroy]

That is displaying the raw wideband data. The information could be used if you're using another wideband like fjo or plx.

Jim

 

[QUIKSUV]

Tell me if the raw data conversion is correct.

From Datamaster:

@ AFR tgt = 12.5, EGR tgt = 42.0
@ AFR tgt = 14.7, EGR tgt = 49.8
@ AFR tgt = 17.9 (decel fuel cut), EGR tgt = 63.1 - 73.3
@AFR tgt = 10.0, EGR tgt = 22.7

Is 14.7 just 50% of 5V or 2.5V?
12.5 is 42% of 5V or 2.1V, which is very close to 12.5
I guess the others at each end are off the AFR tgt scale but the EGR tgt is still the voltage read by the ECU.

Am I right?

 

[leroy]

50% should be 2.5 volts. 60% would be 3.0 volts. You need to compare that to the voltage out chart for your meter to determine the a/f ratio. The diy-wb output is not linear.

In v. 2 of Dig's wideband patch, a lookup table is used to display the actual air/fuel ratio in the a/f target field for folks using the diy-wb.

Is that vague enough for ya? :wink:

Jim