Tuned for 14.7 AFR but goes to 14 when I unplug MVPI?

[weinerschizel]

Maybe is just a coincidence? I am running 1 Bar RTOS tuned Speed Density. When I finished up my fuel adjustments I reenabled closed loop. I left the WB O2 hooked up so I could monitor things. I noticed for some odd reason truck is now running high 13's to 14:1 AFR. I think is odd so I plugged the laptop back in and it started 14.7:1 AFR. I cannot figure out what's up. It seems when I try to log it w/ MVPI hooked up, it goes back to 14.7:1 AFR so I cannot catch it in a log file to trouble shoot. I'm a bit baffled. Any ideas?

13 2023-11-11 263109 PE tuned, RTT OS, MAF DISABLED.hpt
15 LOG D.hpl

[N2speed]

You are logging commanded A/F not actual . Also A/F will always swing some at idle or part throttle

[weinerschizel]

No, I am using a wideband. It was tuned with a wideband and I am logging with a wideband. STFT are giving me 14 AFR instead of 14.7 AFR when I unplug the MVPI and I cannot figure out why. I plug back in MVPI and it shoots up to 14.7 AFR

[gtstorey]

No, I am using a wideband. It was tuned with a wideband and I am logging with a wideband. STFT are giving me 14 AFR instead of 14.7 AFR when I unplug the MVPI and I cannot figure out why. I plug back in MVPI and it shoots up to 14.7 AFR

So you are saying the afr gauge is reading different? I would expect the gauge or wiring being the problem causing a voltage issue.

[jsf55]

Are you earthing the wideband om the same point as the narrow bands

[weinerschizel]

Interesting question... I grounded it to the accessory power. I could check PCM ground to accessory power and see if there is a load there.

I bet when the MVPI & Laptop are plugged in it's tieing the grounds together with the accessory / WB and the PCM through the OBDII port. Genious, I'd have not thought of that.

This is not the issue.

[weinerschizel]

I tuned to 14.7 at cruise... and 12.2 at PE

When I unplug the computer PCM goes down by about 1 AFR.

[weinerschizel]

This issue persists. I wonder if there's a bug in the HPT RTOS.

Grounds are fine, Wideband is correct (calibrated and trustworthy), Speed Density calibration closed loop. I'm NOT blipping throttle.

AFR goes about one point lower than what I'd expect (13.7 from 14.7) and sticks there (showing on Wideband).

The AFR reading immediately reverts to correct ratio 14.7 once just the MVPI cable is plugged in.

What the heck is this???

I think I'm going to change my RTOS back to the factory OS and see if issue persists.