hmm my AEM is off by .1-.2 from MS to the AEM, currently its grounded to ECU adapter harness, but I'm gonna try firewall and parrlel wire running with it as well

 

My AEM is off by this same amount

 

What did you find by hacking their miata ECU? Anything that should/could easily be "fixed" by the end user?

 

I've tried several times to resolve the problem with my car; by changing grounds, adjusting the MS's AFR calibration, and even bought a 2nd wideband that did the same thing. My gauge is reading almost a 1 point discrepancy, gauge reads richer than MS.

I just wanted to clarify... In the event that there is a discrepancy between the AEM gauge and MS, it is assumed that the AEM gauge face is correct. Is that right?

I finally gave up on actually fixing the issue and adjusted my target tables a point leaner than they should be. I'd hate to think I'm tuning to a 12.5 afr at wot.

 

A multimeter tells the tale. MS has an offset.

 

Bunch of wimpy confused ground connections between the various ground pins on the connectors and the circuitry. I beefed em up with some 20 gauge wire. Fixed a problem where there was a 0.2V offset on the MAP sensor reading, which was worth almost a 10 kPa error (lame!).

 

Pulling a Jesus on this thread, but I now have the same issue. The discrepancy in my readings is of ~1.3 points. Which gauge reads correct? I dont see an answer for Pdexta. My WB is a PLX300 btw.

 

I solved my problem by running the ground to the same source as my ECU. It still wasn't perfect but it was damn close. I also suggest compensating for the reading in your AFR target table.

 

DMM's solve all voltage offset problems...

 

I recently soldered all ground wires to ring connectors (rather than crimping only) and suddenly, the old offset in my WBO2 is gone. :wiggle:

 

Well, then who is the correct reading? TS or WB?

WBO2 101 here, how do I measure voltage differences. Also how to I "offset"... is there a table for this. I just went throught TS and I couldn't find such thing. My WB does not have the calibration software LC-1s have.

You're so gangsta

Thanks

 

WB is the correct reading
if there is different reading in TS thats because of a voltage difference from the output of the wideband to the megasquirt.

 

Okay, thanks. I now remembered that when I had the ground to a chassi port the difference was minimal. This time I kept the cable in the cabin. Time to re-ground.

 

You need to measure the voltage input into the MS. But you need to reference it against what the PLX is sending.

for exmaple, if you know the PLX should be at 5v and the MS is only getting 4.5v, you can recalibrate the MS to properly read and interperate the signal.

 

How? is there a voltage/afr table somewhere that I overlooked?

Me is a

 

oh youre still on one of those acient msI machines.

 

When there is a conflict between what is seen on the gauge itself and what is displayed by the ECU, always trust the gauge, and assume that there is a calibration or ground offset problem.

All else being equal, the analog ground for the wideband controller should always be connected to the same ground as the ECU uses for its analog sensors. Ideally, the wideband ground will actually be connected directly to a ground pin at the ECU.

Why not give it the "best" ground possible? Because if the ECU itself is experiencing any kind of ground offset, you want the wideband controller to experience the same offset. That way, the two devices are "in sync" with one another. On my cars, I have always either spliced into an ECU ground wire, or double-crimped the wideband analog ground directly into one of the ECU's own ground pins.

In cases where the wideband system has a seperate ground for the heater, this can be run directly to the engine. This is contrary to Innovate's instructions, however as Ben stated earlier, I believe they state this only to make the instructions simpler for people.

 

No, I have MSII.

Thank Joe

 

Logworks is the most accurate correct? I have TunerStudio and LogWorks displaying within 0.1 of each other, but my analog gauge is reading ~0.3/0.4 off. My grounding is superb. Thanks WB gurus.

 

so alter the output voltge range on that channel until it matches better.