EGO & AFR Rich…Orrr Maybe Not?

[v8power]

I’m trying to figure out why my car is running rich, getting poor gas mileage, and at times the smell of gas. The 1st log is the startup of the morning, idling for awhile, going for a short drive, and idling after the WUE was over. The 2nd log is after a shutdown and started for the 2nd time today and idle. The 3rd log is at idle when I was pressing a little on the throttle.

During most of the logs you can see high EGO volts and rich AFR ratio. However, in the 3rd log with slight throttle increase the EGO volts goes to 0 and the AFR goes lean. For this reason is why the title says maybe not?

I also noticed the Idle Stepper Position at best was at 80. I watched uTube MS2/MS3 Settings Tutorial videos stating it should be at 100. Later on it drops down to 40s & 60s. That may not be my problem, but if I’m not getting enough air it could be a contributor.

I’m using one narrow band O2 sensor on the passenger side (MS2 default). I am fairly new with MS2 (Mustang PNP). I may not have all the settings done right or something wrong with the engine or sensors. I’m looking for advice to help fix my problems.

[v8power]

The 1st log won't load. States too big. Hopefully the other two logs are enough. I may try to get another cold start log if needed.

[v8power]

Here are two more logs, one from a quick ride, and another idle.

[turbo conversion]

With a narrow band sensor I would suggest looking at the spark plugs, they tell all.

I noticed you have dwell set to fixed, I thought with basic trigger it should be set to standard dwell.

David

[v8power]

David,

Thanks for the find. I don't remember changing that, but I changed it back to Standard Dwell. I attached a couple more logs after the change. Still getting high EGO and 12 to 1 AFR. As far as the plugs, they are E3s, but I didn't pull them out to look at them yet. I'm sure it's running rich. I used to get 19 mpg, now I'm getting 13 mpg.

Awhile back, I did find one of the plugs cracked and had to replace it. Would a dead cylinder cause these readings?

Tom

[slow_hemi6]

How can you get 12:1 AFR. A narrow band sensor is incapable of measuring anything other than 14.7:1 and maybe 0.1 either side. Other than that it tells you nothing. If a narrow band could do the job of a wide band there would be no need wide bands.

[turbo conversion]

You really need a wide band ego sensor for tuning, with out it you are tuning blind except for reading the spark plugs.

Is this a boosted engine, the reason I ask is your AFR and SAT map are set up for N/A but the VE MAP is set up for boost.

David

EDIT: word

[v8power]

I can't tell you how, I just use the Tuner gauges. The EGO is 0.0 - 1.0 with .5 being the ideal balance. The AFR shows 12:1 (see attached screenshot).

No this is not a boosted engine. I'm new to aftermarket tuning. So that's why I bought the plug-n-play version. The VE MAP is what came with the ECU. The only thing I've done was change the VE numbers in the idle area so idle wouldn't hunt anymore.

I've been watching uTube videos on MS2 set up, but didn't see anything about different VE MAPs. If it's set up for boost, then that would explain the extra fuel. How do I get the correct VE MAP?

I apologize for my ignorance, I am truly a newbe here!

Tom

[slow_hemi6]

Tuner studio will let you select any of it's gauges but if the gauges are not getting real information sent to them they will read garbage. That AFR gauge only works with a connected and configured wide band. The Ego Volt gauge is however working correctly.
This is the typical output from a narrow band sensor. They were only made for closed loop targeting of 14.7:1 afr in highway cruise.