[vasillalov]

Why would the BMS DP fix mess with the AFRs? The AFR is controlled from the pre-cat sensors. The BMS DP Fix messes with the output of the post-cat sensors, tricking the ECU into thinking that the cats are present and working correctly.

[bryce]

Originally Posted by vasillalov

Why would the BMS DP fix mess with the AFRs? The AFR is controlled from the pre-cat sensors. The BMS DP Fix messes with the output of the post-cat sensors, tricking the ECU into thinking that the cats are present and working correctly.

the secondary oxygen sensors do have an effect on the a/f ratio. unlike other platforms, they do more than just measure catalytic convertor effeciency/effectiveness

[EastCoast335i]

Originally Posted by vasillalov

Why would the BMS DP fix mess with the AFRs? The AFR is controlled from the pre-cat sensors. The BMS DP Fix messes with the output of the post-cat sensors, tricking the ECU into thinking that the cats are present and working correctly.

+1 ?

[vasillalov]

Originally Posted by bryce

the secondary oxygen sensors do have an effect on the a/f ratio. unlike other platforms, they do more than just measure catalytic convertor effeciency/effectiveness

Is this something you have measured yourself?

[ATP]

Originally Posted by vasillalov

Is this something you have measured yourself?

I thought Dz posted somthing about this on the other forum. Just wish I remember which thread it was in.

[bryce]

Originally Posted by vasillalov

Is this something you have measured yourself?

yes, i did it on the accessport. you can measure it yourself, too. here's a few quotes from people discussing the rear o2 sensor's role in a/f ratios:

Originally Posted by shiv@vishnu

Rear lambda sensors do have influence on fuel trims because they are known to be very accurate around stoich. So the DME uses them as reference for lambda calibration/plausibility checks. Which is why you will trigger trimming codes if one of the rear sensors starts to fail. Or if you are using a "downpipe fix" that is too strong. During engine load when AFR target is rich, they are largely ignored since they aren't accurate on that side of the response curve.



Not sure how that could stir the pot since this is already implemented. The factory lambda sensors are fast-acting widebands. What's more is that they require almost no exhaust pressure compensations to provide accurate readings. This isn't the case with most aftermarket widebands that I've tested.

my 2c
shiv

Originally Posted by dzenno

All you would need to do is plug a Cobb AP into your car, unplug your rear o2 sensors or run the stage1 map and be catless and we all know what happens then, you get a CEL for cat inefficiency...ONCE that is triggered, the DME will run a different fuel "mode" on your car...how that reflects on power at this point I can't say for sure but it does impact "fueling"...if you'd like any further details don't hesitate to ask cobb or post in their thread...

another example: when a car misfires, fuel mode changes as well, different from the above...normal running fuel mode is fuel mode 2, when a car misfires DME goes into fuel mode 15 (fuel system shutdown) to prevent damage to your catalytic converters from unburnt fuel...it goes back to 2 once you restart the car if everything is fine and no more misfiring

there are literally massive numbers of monitors in the dme and these are just some of them

[bigdaddycane]

Bryce,

Any issues with installing the DPFix and leave the JB4 installed and change to Map 0 for the test?

[bryce]

Originally Posted by bigdaddycane

Bryce,

Any issues with installing the DPFix and leave the JB4 installed and change to Map 0 for the test?

you just have to turn off autoclear. otherwise, that would work fine


not sure if map 0 disables autoclear or not, but i'd still disable it via usb cable and laptop

[bryce]

oh, and put 50 miles on the car after you disable autoclear. readiness takes a while to be set, after you've turned off autoclear or cleared codes

[bigdaddycane]

thanks

yeah, I did know about putting miles on the car first. I have until November to prepare for my emissions test.

[vasillalov]

Good info here! My emissions testing notice came in yesterday so I'd have to play around with the DP fix and then watch what happens in INPA.

[themyst]

Originally Posted by vasillalov

Good info here! My emissions testing notice came in yesterday so I'd have to play around with the DP fix and then watch what happens in INPA.

I just tape the dp fix bulb to the top of my ecu lid so I can adjust on the fly... If you want to check readiness with INPA.

[itsmeek]

Or just run an o2 simulator, for example:

http://www.o2simulator.com/

[bryce]

Originally Posted by itsmeek

Or just run an o2 simulator, for example:

http://www.o2simulator.com/

that's what the bms dpfix is

[itsmeek]

I have no idea how I missed that, apologies.

[Joshboody]

anyone know the difference between the bms DP fix and Procede's. I just reversed my harness the other day since I was in the box for convenience. And noticed BMS has an extra in/out to the DP fix and Procede has a pass-thru in this location.

[jaymd123]

I followed this method exactly without any "dp fix" and achieved readiness...so I'm not sure why everyone is saying you can't do it with a tune. Obviously this was done with a Procede but no other "hardware" fixes for the DP's.

http://www.e90post.com/forums/showpo...7&postcount=16

[Joshboody]

Originally Posted by jaymd123

I followed this method exactly without any "dp fix" and achieved readiness...so I'm not sure why everyone is saying you can't do it with a tune. Obviously this was done with a Procede but no other "hardware" fixes for the DP's.

http://www.e90post.com/forums/showpo...7&postcount=16

Procede has it built in... what O2 mod value did you use?

[bryce]

Originally Posted by Joshboody

anyone know the difference between the bms DP fix and Procede's. I just reversed my harness the other day since I was in the box for convenience. And noticed BMS has an extra in/out to the DP fix and Procede has a pass-thru in this location.

Originally Posted by jaymd123

I followed this method exactly without any "dp fix" and achieved readiness...so I'm not sure why everyone is saying you can't do it with a tune. Obviously this was done with a Procede but no other "hardware" fixes for the DP's.

http://www.e90post.com/forums/showpo...7&postcount=16

older procede's had a dpfix built in. newer procedes (v5) have the same capability, but you have to modify the harness to have the dpfix available. you do turn off canclear and change o2 modifyer to 50%. most people don't modify the harness since there's not a lot of info on this, and it's far easier to just wire in a dpfix temporarily.

[bryce]

Originally Posted by Joshboody

anyone know the difference between the bms DP fix and Procede's. I just reversed my harness the other day since I was in the box for convenience. And noticed BMS has an extra in/out to the DP fix and Procede has a pass-thru in this location.

they essentially do the same thing. it's a resistor that modifies the secondary o2 sensor readings. procede has it built in, but you have to modify the harness to have that capability.

[Joshboody]

Originally Posted by bryce

they essentially do the same thing. it's a resistor that modifies the secondary o2 sensor readings. procede has it built in, but you have to modify the harness to have that capability.

yeah I know, but Procede is O2s merged into 1 input to procede and 1 output to ECU

BMS is the same as above, but with extra in/out to a pin that Procede doesn't use.

[bryce]

Originally Posted by Joshboody

yeah I know, but Procede is O2s merged into 1 input to procede and 1 output to ECU

BMS is the same as above, but with extra in/out to a pin that Procede doesn't use.

i think the bms dpfix wires into both the rear o2 sensors. the install instructions allow the wires to be interchanged between 2 or the 3 wires used. procede, as you posted, is merged