MSPNP 99-00 o2 wiring
 

Hi All,

I have one of the new MSPNP9900 for my 99 miata. I installed it and got it running so that was good. I then installed the LC-1 along with a VEI gauge. I have programmed both LC-1 outputs with the same 7.35-22.39 settings. My VEI gauge is working great. The MS either does not see the wbo2 voltage or something. I changed the profile info to wideband, I reset the AFR table to LC-1 and I changed the EGO to wideband as well.

Do I need to wire the wideband to one of the alternative o2 inputs? If so, which pin is it because I cannot find any info on the pinouts for the 15 pin connector?

Oh, I did ground to the ecu ground and I am getting what looks to be the proper voltage (2.3-2.5v) going to the ecu via the O2 sensor connector and original harness.

Thanks
Chris

Edit: I found the MSPNP general manual and it shows pin 14 to be the right one but I want to make sure that it applies to this new model.

How do you currently have the LC-1 output wired to the ecu? I attached a pinout diagram.

I attached the LC-1 output to the original o2 sensor connector by the coilpack. I am using an ampseal j series connector just like the original o2 sensor and have hooked up to the black/yellow sensor wire. None of the other three wires are hooked up.

Pretty sure you have to set them differently...like this:
Attachment 52508

My gauge has slightly different colors on the wiring but yes that is they way it is wired with the exception of the yellow wire is going to the gauge and the brown wire is going to the MS. What I am thinking is that the brown wire needs to go to the wideband o2 input instead of the regular o2 input that is fed by the harness but I don't know which one that is on the additional 15 pin harness.

I'm just going to quote this:

OK, so I went ahead and stuck the wideband sensor wire to the #14 pin on the 15 pin connector and shazzam it works. Lesson learned-the MSPNP likes to see the wideband through the alt. input port.

The gauge and the wideband are reading slightly different AFR's though ( .3 higher on the MS). How does one tell which is correct? They are both set to the same scales and seeing the same voltage for what I can tell.

I saw a thread on adjusting the voltages using the AFR calibration tool. Which voltages would you correct though?


Thanks
Chris

The gauge is correct. The MS shows a different value because there's a discrepancy due to differing grounds. You need to either use the same ground as the ECU for the gauge, or play with the custom wideband values until they line up.

There's been 3-4 posts within the last month or two about this issue, with a bunch of additional info.

I am using the ECU ground for both the gauge and the MS so I will play with the custom wideband values.

That isn't the usual way now, but you can do either one as long as you set the right wideband settings in the AFR calibrations.

The gauge was showing .2-.3 richer than the MS and by the smell I was more inclined to believe the gauge. I went into the AFR calibration setup and entered the following values: .25v=7.35 and 5.0v=22.39 and now they sync perfectly.