So now that I have about 1,000 miles on my car it’s time to adjust the air fuel ratio (mixture).
It generally runs good. However, it is a little rough before the engine is fully warmed up. Also, when I took it in for the initial wheel alignment the mechanic told me he thought it was running a little lean.

My plan is to use a wideband oxygen sensor to measure the AFR (air/fuel ratio) and adjust the MPS (manifold pressure sensor) to achieve an AFR of 12.5 at full load or WOT (Wide Open Throttle).

I purchased a new Innovate Motorsports LM-2 Air/Fuel meter on ebay for $300.00. I originally wanted to log the results on the LM-2 SD card , however I could not get the LM-2 to log data on the supplied SD memory card. After a few calls to their tech support I was able to connect a laptop to the LM-2 via the supplied USB cable. The laptop then displayed the data (AFR) and record it to a file. I also wanted to record RPM but I could not get it to read an accurate value. The LM-2 would be a great unit if it only worked. Also, the customer support and manual are not good. In the end, I was able to get it to log the AFR which was what I really needed.

I drilled a hole in the exhaust muffler collector and welded in the O2 sensor fitting. It was cheaper to weld in the fitting (since it came with the kit) than buy the exhaust clamp for 80 bucks. Since this is not a permanent install I just ran the wires into the engine compartment and thru the engine lid, thru the passenger window to the passenger seat. The oxygen sensor is connected to the LM-2 and the LM-2 is connected to the laptop via a USB cable.
The laptop is running the supplied Logworks software and can display (and record) the AFR in real time on a graph as well as a digital gauge.

Once I got the Logworks software to log the AFR results real time, I made some initial baseline runs up a long hill to get a steady AFR plot at full throttle or WOT.
The baseline WOT AFR was about 13.5 which means it was running lean.

Next, I removed the MPS from the car and removed the epoxy plug covering the Full Load Stop screw. There are two adjustment screws, one inside of the other. I needed to adjust the inner screw without moving the outer screw. Luckily, I was able to turn the inner screw without turning the outer screw. If the outer screw turns there is a tool available from Tangerine Racing that allows you to turn either screw. I initially loosened the inner screw CCW 90 degrees and made another run. It helped but the AFR was still high. I then turned it another 90 degrees tor a total of 180 degrees. The WOT AFR was right on 12.5 and the car ran so much better. It was a lot smoother and the roughness when the engine was cold was gone.

Ok, now that your WOT is set what is your Part load AFR?

You're a couple of weeks ahead of me, Steve. Nice work. I may have questions for you at some point soon, but can you first tell us what year/engine you're running?

Thanks-

rc

Nice work!
What kind of data do you get at idle or tuning in the garage?

On a previous thread, I argued that you could not get valid data unless at WOT/Load which your logs seem to indicate.

Just curious if it is my setup (I use the LM-1).

I also built a data logger that can log the serial data from the AFR and I also have the TC-4 that can log 2X EGTs & 2X CHTs.
You can get a logger just like mine from innovate (the PL-1) off ebay for about $100 so you can lose the laptop.

In the next week or so I will have my newest datalogger working that can log AFR, EGTs, CHTs, oil press & temp, throttle position, RPM, MAP, and fuel pressure.
It will display all of that on a droid phone in real time.

OK, you adjusted the screw that sets the idle mixture. And you can get 12.5 at WOT. I am wondering about how the fuel mix is changing at different throttle positions and loads. Can you give us more infer? My problem is I can get everything but cruising with the throttle just barely open. Then it is too rich. There are three adjustable screws, but I cannot get the right combo quite yet that allows drivability, head temps in range and economy. Keep at it.