Car is stalling after startup. Please help
 

'2000 Miata with Reverand-built MS2. Installed and tuned in July.

The car has been stalling after the initial startup while trying to drive off. The RPM simply drops and doesn't recover. The issue seems to go away after the car is fully warmed up. Of course now that it's 30F here the issue is more pronounced. It almost feels like ECU is not telling the car to get more fuel after the gas pedal is released. Additionally, the idle at the very beginning is lower than 1,100 rpm that it's supposed to be. I'd think that warmup idle would be set higher until the car gets to temp, no?

Additionally, the Check Engine light has been coming on at exactly 200F, not 220F as intended. We've tried to troubleshoot this for a while to no avail. But I don't think that is related to the stalling issue. Also, starts are pretty hard, takes quite a bit of cranking before it catches on if it's been sitting for more than a few hours. No problem on a race car but a bit annoying.

My tuner suggested: "I would try to reduce the coolant temp related enrichment a bit at those lower engine temps. I cannot recall the exact name in the MS but it provides a % of enrichment vs coolant temp(I think warm up enrichment, or WUE). If that table is making the mixture too rich during warmup it can cause what you are describing"

Any thoughts on this? Any and all help would be appreciated.

ounds like not enough fuel.

datalog the event and post it alogn wth your msq.

Thanks! The .msq file is attached. My .msl log file is 2.62 Meg so I can't upload it. Is there a way to get it to you? If I could cut half the datapoints beyond the first couple of minutes that are important... but not sure hot to do that. Please let me know what you think.

One more things. I've just compared the Current.msq (same one as I've posted above) and the file my tuner sent me (attached in this message as final.msq). It appears that all temps are in C in "Current" and look like they are in F in "Final".

I'm totally lost with this. One probable cause is that my tuner was using his own computer and software and I'm _sure_ he set everything on his computer in Fahrenheit. My Tuner Studio is set in Celsius. So when he uploaded the file into the car at the end of tuning... what happens when I connect to it with my Tuner Studio and file is saved as "Current"?

OK, here's today's log file with a couple of stalls. I'm still very confused about C vs. F setting as described above.

Brain and others, please help!

I think it is a C to F conversion, without looking at the files. It might also explain the check engine light coming on too cold. You have all of the info you need to troubleshoot, or pay your tuner to fix it.

32F is about 0C, so if you use the same enrichment Y values for F as C, you get a lean condition by comparison. It shifts your graph to the left.

It could also be a bad coolant temp sensor reading, bad offset, bad sensor, etc.

its a setting within the software.

Being born in Europe I can convert C to F.

I've re-set TunerStudio on my own laptop to F. Uploaded my tuner's file. Burned it into ECU. Get same behavior/stalling from the car after startup until it's warm.

The oddest thing is that when I compare "Current" file to the one tuner sent me (the one I've uploaded and burned in, the one shown above as "final.msq"), the comparison still shows a bunch of differences, this time in F. Why is that?

BTW, check engine light at 200 F should have nothing to do with coolant sensor itself or F vs. C. It's programmed somewhere in MS, no? And should be 220F according to Reverant.

The check engine light is not adjustable on your MS, its only adjustable in the latest version. Its pre-programmed through the expansion board to come in at ~217*F, but apparently in some cases it does come in earlier. I have had a couple of people tell me that when they swaped in a new sensor, it went away. This has to do with sensor-to-sensor variance.

No, for the cold start issue etc. Start a new project in Farenheit. Connect to the ECU so that TS loads the settings from the ECU, and then save the .msq and email it to me.

Should I replace my coolant temp sensor with another one to try? Or is it a sensor on the board?

As far as starting a new project - will do that and email info tomorrow.

OK, I figured out the F vs. C issue by starting a new project as Reverant suggested. However, there's still stalling. Here's the log file.

Calibrate your TPS, it shows 1% in most idling situations.

You also need to increase your cranking PWM idle values.

Reverant, I've re-calibrated it about 3 times yesterday. For some reason it shows that 1% after calibration. Should I enter/adjust the "low" number manually?

As far as PWM values, what would you recommend and where/how to set them?

BTW, I want to publicly thank you for helping out with this. Much appreciated!