Quick stupid question. Does PNP run closed loop?
 

I managed to screw up my WB O2 sensor while installing inconel studs on the turbo. Either the penetrating lube I used to get the old studs out killed it, or banging it against the tranny trying to get the DP off & on did... either way I need a new one.

In the mean time, does the PNP MS1E I have ever run in closed loop under normal (track) driving? Or to put it another way, is there any risk of driving the thing with a bad O2 sensor?

Thanks for putting up with my ignorance

me=>:noob:

Edit: Strike that, reverse it. x.x

Depends if u have it turned on or not

Depends on how you have it configured.

Basic Settings -> Exhaust Gas Settings, and
More Settings -> Lambda AFR Settings.

If you want to disable it, change "Authority" to 0 in the first menu.


Closed loop means it IS changing fuel based on AFR.

Closed loop is when the ECU effects changes based on the O2 sensors output, what you're talking about is open loop.

aka you have it ass backwards :)

Thanks for the help! let me make sure I have this right:

my exhaust gas controller authority is currently set to 5%, so it has been running in closed loop during part throttle. I can disable closed loop by setting the authority to 0, which means its going to run solely on the fuel tables which will obviously be less than optimal, but should be safe... right? (of course this depends on how safe the fuel tables are, and I'm going to ASSume they are ok)

correct.

BTW, gentlemen, is wideband really needed for daily operation? My tuning guy is telling me that i can run on two narrow band O2 sensors and he can tune the car by shoving a long probe up the short custom exhaust that I have.

Granted that, can I drive the car after that with just regular O2 sensors? What's the disadvantage to that?

I'm (obviously) no expert, but I did see an option to run the closed loop off of a narrowband O2 sensor in megatune, so I'd bet you can. And of course, if you had well tuned part throttle fuel tables you could just run open loop with no O2 sensor at all.

BTW, I had a slightly intelligent moment and tried "resetting" my innovative WB 02 and it seems to have fixed it :)

I'd get a different tuning guy.

Advantages of WBO2:
1. Autotune.
2. Even if you don't autotune, you can use Megalog Viewer and get a better fuel tune than your "tuning guy" could ever give you.
3. You can keep an eye on your AFRs in boost. A NBO2 does not output a usable signal at those AFRs. Injectors can clog after all. Would be a shame to blow an engine for something like that.

Other than these relatively significant advantages, there's no reason at all to run a WBO2.

Not sure why boost is being mentioned. Neither am I sure how to tune a race car without dyno.

Because that's when you're most likely to explode your engine? Only fuel can be tuned reasonably well off a dyno.

I have a normally aspirated car. What boost?

can he tune your carb too?

might as well convert to 2-stroke too

The question is fairly serious. After the car is tunes with wideband, is MS looking at wideband signal for normal operation?

see post #3.

Thanks, Brian. I saw it and understand it.

Let me re-phrase more specifically. Once the normally aspirated car is tuned, is there any advantage in running wideband sensor?

considering tuning on NB is absolutely pointless, yes.

/\ Interesting. Why is that? Is the stock setup "maxed out" from the factory?

because narrowbands output a bunch of nonsense; I'm not even sure you can consider tuning on a nb sensor, tuning.

Maybe I misread.

but yes, there's still an advantage to always running a WB sensor.

No I meant with a wideband. Say you got MS and a wideband but otherwise stock nb, would you pick up the 10-15hp the na's tend to pick up otherwise stock?

nb, in my case = narrowband.


of course youll pick up power tuning an NA, NB, NC miata running MS.

lol abbreviation phail.

Yes, you can run closed-loop from a narrowband sensor, but only at 14.7 : 1. Wideband is required to run closed-loop at richer or leaner mixtures than 14.7 : 1.

This is not correct.

The term "closed-loop" in the context of an EFI system means that the ECU uses the reading from the O2 sensor to adjust the amount of fuel delivered, seeking to achieve a specific target mixture.

If no O2 sensor is present, then the system cannot, by definition, operate in closed-loop mode.

OOOPS! My bad, I meant to say open loop. Thanks for catching that. This thread is full of bad communication.

OK, I ended up with 3 oxygen sensor in the exhaust. 1 wideband and two OEM narrowbands. This should be OK as far as I can tell? MS should be just ignoring narrowband signals, right?

If the narrowband sensors are not physically connected to the MS, then it will obviously ignore them. (It's not telepathic.)

If the narrowband sensors are connected to the MS, then it may or may not ignore them, depending upon the configuration of the software.

They are physically connected through the harness to MS.

In Tuner Studio I've set "Wideband" for Oxygen sensor in the original configuration. Should this be enough to ignore the narrowand's signals?

lol. you have much to learn.

You think? :)

Seriously, I am trying to learn. Any help would be greatly appreciated.

You haven't told us anything about your car, its wiring, which MS you are running, etc.

Is this, for example, an MSPnP or a regular MS?

If so, then by default the stock forward O2 sensor is connected to the MS.

If you have added a wideband, we'll need to know how that's wired and what, if anything, you did to disconnect the narrowband sensor from the MS.


The software selection for narrowband vs. wideband cannot cause the MS to physically look at one sensor vs. another- it simply describes to the MS how it should interpret the one O2 sensor signal which it sees.

Joe, the car is '2000 normally aspirated. I'm running Dimitris (Reverant) built MS PNP for '99-2000 Miata (last group buy).

The wideband is connected through LC-1 so I assume (incorrectly?) that MS reads it on a different pin than it would read a front OEM O2 sensor. I did nothing to disconnect the stock O2 narrowband from the stock harness. I am not sure that Dimitris' MS PNP is actually reading the narrowband sensor at all.

You'll need to contact Reverant directly on that.

A "normal" MS has only one O2 sensor input pin, which is used for either a wideband or a narrowband, depending on the wiring.

I know that Reverant's MS's are a bit different and the wiring package which he supplied will determine what is connected to what. It's probably safe to assume that his wiring package ignores the narrowband sensors entirely and has connected only the wideband.

Joe, thanks! I exchanged emails with Dimitris and he suggested shorting O2 heater ground supplying pins from ECU (1U and 3V as far as my manual tells me) to the ground in the harness.

Just so this might help someone in the future:

O2 sensors in at least '99-2000 cars get their +12V to the heaters directly from ignition (BlackWhite wire in O2 sensor harness). Ground, however, is supplied by ECU on aforementioned pins 1U (front sensor) and 3V (rear sensor). Tying the heater ground wires (Purple/White for the front sensor and Red/Yellow for teh rear sensor) to Ground would effectively keep the heater circuits on whenever the car is on.