TunerStudio AFR guage seems wrong

[adamnreeves]

A friends car that I am helping him tuning at the moment. Has a 10point4 Wideband controller simulating LC-1 output. AFR = 2V + 9. He has a separate gauge in his dash to the controller. TunerStudio seems to be showing around 1 AFR richer. I took some datalogs for about 1minute at idle to check the AFR was 13.5, gauge on dash showed 13.5 but TS showed 12.5

TunerStudio beta 1.21
Megasquirt 3 MSextra 1.0.5


P.S. I tried custom controller and set 1V = 11 AFR, 4V= 17 AFR. Same result.

[Sam280Z]

Are the AFR gauge, MS controller, and WB controller all grounded to the same place?
If not, they should be.

[LT401Vette]

simulating LC-1 output. AFR = 2V + 9

That is not the formula the LC1 uses....
The LC1 Default is:
AFR = 3.008 + 7.35*V

Or the LC1 programmed as an LM1 or PLX:
AFR = 2V + 10

Is that what your WB is programmed to output, or is it programmed to simulate an LC1?

P.S. I tried custom controller and set 1V = 11 AFR, 4V= 17 AFR. Same result.

That should not be the same results. in any case, but if it is still not reading correctly, there is most likely a grounding issue. Where is you MS grounded compared to your Gauge?

When you said:

I took some datalogs for about 1minute at idle to check the AFR was 13.5, gauge on dash showed 13.5 but TS showed 12.5

I get that TS showed 12.5 and the gauge showed 13.5, but what was the reference for the baseline 13.5?

[adamnreeves]

Thanks for the replies guys. I wont see this car now until the weekend. Could be right on the LC-1, it may be TechEdge. I did note that the output was the same as my AFR which is a TechEdge 2J1.
What I can say is that it was consistent before we upgrade from MS2 to MS3 and took the latest versions of everything.

I'll do some more investigations the weekend.

[adamnreeves]

I've been able to check which AFR settings are used, TechEdge Wideband Linear which I am fairly certain is AFR = 2 * volts + 9. Also we did some live tuning (VE analyse Live) and that seemed to tune with regard to the AFR as shown on the gauge in the dash, not the AFR shown in TS.

[LT401Vette]

Also we did some live tuning (VE analyse Live) and that seemed to tune with regard to the AFR as shown on the gauge in the dash, not the AFR shown in TS.

TS would be using the same AFR the gauge is showing for VE Analyze unless you have multiple AFR's and have the gauge set to the wrong one. So I would be careful if you believe you have a setup error causing afr to be incorrect. Normally with a single WB the only afr in question is the OutputChannel afr1 which is reported to TunerStudio from the firmware. That is what is displayed on the gauge, used during VE Analyze or any thing else that subscribes to the OutputChannel afr1.

Once you know you have it calibrated with the right formula, use a volt meter to check the input voltage to the MS. Make sure they are consistent with what you are expecting to see.

[adamnreeves]

Thanks for the reply Phil. Yes appreciate it is the same channel but with everything seeming to match except the AFR gauge in TS I was wondering if it takes an ADC and applies a conversion to show as AFR and I was thinking that might have a problem. But I appreciate I have made 5 from 2 + 2.

This is my plan. I have spoken to my friend and advise him to do this.

Add a lambda gauge next to the AFR gauge in TS and place the laptop next to the AFR Gauge in the car. Take data log, and also video the laptop screen with the in car AFR gauge and start the car up which has been pre-warmed. We can then use the ignition event as the start position of the data log and video and see where the difference is.

This to be done after checking the ground, wiring and also the output voltage level from the WB controller (14point7 SLC). Also double checking the firmware calibration which I have done several times anyway. BTW, if you select known WB controllers from the TS calibration menu the reference points on the same dialog do not update, they are greyed out but still it makes you think something is wrong.

Anything to add to our test?

[LT401Vette]

I was wondering if it takes an ADC and applies a conversion to show as AFR and I was thinking that might have a problem.

That is the model for MS1, but with MS2 and MS3, TS only uses the conversion formula / inc file to generate the calibration tables when you run "Calibrate AFR..."
After that the firmware does the look ups on the calibration tables sends back already converted afr based on those calibration tables.

[adamnreeves]

Thanks for explaining that Phil. I spoke to my friend last night regarding the checks. Asked him to dig out his wide band controller manual and check the voltage output Yes, it is different!!
You can relax

it gives 0v to 5v which is linear to 10:1 to 20:1. So I have talked him through re-calibration. He tells me now that the dials look more consistent.

We going round Oulton on Friday