dual o2

shaodome · Post by **shaodome** » Mon Oct 17, 2005 9:26 pm

Maybe I missed it...but does MS2 support a 2nd o2 sensor input or plan to?

Post by **grippo** » Tue Oct 18, 2005 5:21 am

Yes it does along with dual afr target tables, but I don't know if anyone has ever used them.

shaodome · Post by **shaodome** » Tue Oct 18, 2005 5:52 am

I see is supports dual WB, but what about the narrow band sensors? On my V6 I noticed a pretty huge difference between the heads and the required o2 corrections.

EDIT:

What processor input source is the code looking for on the MS2 for the 2nd narrow band sensor. I know Extra is using JS5 along with the little circuit.

midnightblue · Post by **midnightblue** » Tue Oct 18, 2005 7:09 am

I have a dual lambda install underway at the moment.

MS-II with two LC-1s on a V8

I haven't run it yet, but with a bit of luck I'll turn the key this weekend.

I've built a second input circuit in the proto area and hooked it into JS-5. I following the v3 pcb schematic for the other O2 input, rather than the one specified in the -extra documentation. I figured that the two circuits should be as close as possible to identical.

We'll see if it works soon enough!

Post by **grippo** » Tue Oct 18, 2005 9:54 am

No the dual tables are only for wideband. You could treat the NBs as WBs and fool the processor, but it uses a different algorithm in closed loop. NB uses a user input fixed step to correct, WB uses a calculated step based on the % difference between measured and target ego. It should work, but I don't know if it will work as well as the NB algorithm.

If there is a big difference between the 2 cylinder heads I would try to find out why - using closed loop ego to correct for this is just a crutch.

The two EGOs come in on ADCs 5 and 6. These go to pins 28 and 29 on the 40 pin socket.

shaodome · Post by **shaodome** » Tue Oct 18, 2005 12:12 pm

Well...maybe huge was the wrong word...but there was a MPG increase in the 2-3 range when going to the dual o2 sensors. It would be nice to be able to use them the same way they are used in EXTRA eventually. I'd do it, but I am all thumbs when it comes to programming.

danc8000 · Post by **danc8000** » Mon Apr 03, 2006 8:27 am

Did you get your dual widebands wrking OK? Are you displaying and logging both signals in Megstune?

midnightblue · Post by **midnightblue** » Mon Apr 03, 2006 8:57 am

Yes, it seems to work very well.

I have both widebands feeding into MS-II V3.0 pcb, running dual VE tables. Each bank of the V8 is wired to one injector channel, with it's pulse width calculated from the appropriate VE table, and EGO correction supplied by the wideband on that bank.

It's all in the current code, take a loo in your ini file, the variables are called egoCorrection1 and egoCorrection2. I think you just need to add the gauge definition to the ini file and Megatune will do the rest.

I think Eric has also fixed it now so that you can use Autotune on each of the two tables. In theory they should be identical, in practice there are small differences between even the two banks of the same engine.

danc8000 · Post by **danc8000** » Mon Apr 03, 2006 12:30 pm

Thanks for the reply.

Sounds like a nice setup you've got there. Hopefully get mine all sorted in the next week or two...