RPM not showing above 4000 RPM
 

Finished my DIYPNP MS2 extra install this past weekend. Got the car, what I thought, running pretty well. It's an exhaust and intake 1.6L car (around 1950lbs) and the MS really freed up some midrange torque in the car. So I got it to idle well (still high ~1200) but no tip-in stumble that I can feel.

I went to do a few pulls on the interstate and got back to read the logs. For some reason the RPM shows 3440 max and I only reach 87.5 kPa, which seems odd to me. I don't really know how to fix this issue or where to look.

1.6L
intake
exhaust
IAT

time 295 to 315 is the cleanest pull.

What MAP reading do you see with the key on and engine off? And are you close to sea level, or up in the mountains?

I see no reason to doubt the RPM reading in the log you posted.

Did you rev it higher then 4k rpms?

I will have to check the MAP signal later on this week when I get home, but I am kinda in the mountains, the Appalachians.

Yeah, I did 3 pulls on the file I linked, all from about 3k rpm to redline ~7000 rpm. You can see the duty cycle climb pretty sharp (atleast I thought it was pretty sharp). Unless there is some reason the logs would stop recording. The screen on the computer turns off automatically for battery life, but the log file looks like the whole 6 miles that I drove.

Shouldn't barometric correction make it 100? Or does baro correction work differently than that.

This is what I thought, honestly. The car is running great the way it is, but I am not sure how safe this tune is. I have an autocross on Saturday so I would love if someone took a look at my tune as well. :party:

Barometric correction COMPENSATES for the ambient pressure not being 100 kPa; it does not make the ECU pretend that ambient pressure is not 100 kPa. Atlanta is not exactly high up in the mountains, and ambient pressure here is usually around 95 kPa.

It may be that something simply stopped the log before it was revved to redline.

Matt, thank you for taking the time to look over my log. You are correct, there was something stopping the log. The car is extremely stiff and very harsh and I don't think I screwed in the serial port plug. I believe that the vibration may have caused it to lose connection. I was able to do another run today and it recorded everything. My afr's still look noisy, hopefully VEAL will take care of some of it.

I am extremely happy with this MS unit and I love the support the community, and company, has behind it. Again, thanks for taking the time. :likecat:

Is this lean spike normal when inputting quick hard throttle inputs, such as when I autocross? I don't have a vTPS in the car, so I am making the assumption it is a lag time between the MAP sensor reading and the O2 reading being adjusted in the ECU.

https://www.miataturbo.net/attachmen...ine=1444952613

Yes. When you stab the throttle you add a shit ton more air. Then your ecu realizes it and adds fuel.

Thats what Accel enrichments are for.

So is there some literature on how to adjust AE without a variable vTPS? Map based AE seems lacking.

Yes. It reads: Get a vTPS.

Just incase one of you newer guys to tuning is reading this thread during a search. I found some great information on the DIYPNP site explaining how to tune AE ("acceleration enrichment").

DIYautotune VE enrichment tuning

....and Aidandj is right, it does, on a basic level, read get a vTPS.