tfbmiata

Hi All - I got a used MS3PNP for my 01-05. I loaded the base map and clicked burn. When I attempt to crank the car won't start. After about 3 or 4 cranks there sounds almost like a misfire and the engine stops dead. I was able to get it to start one time by switching over to Fixed timing rather than timing table, but that only started once. I'm curious if anyone has any ideas. I have run the vacuum line and otherwise just plugged in the ECU into the stock ECU plugs. With the stock ECU everything works normal. About the only other thing I can mention is that with the MS3 there is an audible hum when the key is in the "on/ignition" position. I was able to trace it back to a hum near the throttle body. The pitch changes when I open/close the throttle so I'm guessing something with the TPS? I dont know why there would be a hum, but hoping that gives some information to you to assist.

Z_WAAAAAZ

Attach the current tune and a datalog if you can. Takes much of the guesswork out of it for the tuning wizards on here.

redursidae

Yes, post your tune and a log. The humm could be your idle valve set to run when stalled.

tfbmiata

No problem. Sorry, I'm a noob for this. I hadn't planned on needing to troubleshoot just to turn it on so I haven't learned much. In all honesty I was just trying to make sure it worked since I bought it second hand. I'll get a log of it and a copy of the base map from DIYautotune.

Z_WAAAAAZ

No sweat, many of us have been there before haha.

You check base timing after swapping the ECU in? That'd probably be a good place to start while waiting for someone to review your tune.

tfbmiata

Good question. I didn't check it. I didn't think I could check timing without the engine running, but also it was just on stock ecu and running normally with no other changing. Can the base time (which I understood to be a physical thing between the relative crank position and cam timing) change with just the ECU swap? I had planned on it once it turned on as the instructions said, but never got that far. I'll try and get the tune and log uploaded tonight when i get home to the car.

tfbmiata

Morning all - thanks for the help. Looks like it was an issue with the basemap. The trigger angle offsite (deg) was a +2.0 and needed to be at +8.0 to have base timing with a timing line match up to 10. I do still have the weird hum. The sound occurs with the car on and running or on and not running. The tone of the hum changes based on pressing the gas pedal. Any thoughts? I ran the TPS calibration but that didn't seem to change anything.

redursidae

Like I said, it is likely the idle valve, but I'm just guessing without seeing your MSQ or a video. If you're using the same basemap I just downloaded from DIYautotune, it has the idle valve Frequency set to 306Hz. Try setting it to 511Hz.

tfbmiata

Sorry was so excited to post it is running I forgot you said that. I'll try that and upload the tune I'm using whether it works or not.

tfbmiata

511hz definitely helps. The tone is way quieter though still exists. Is that normal?

Attached is my current tune.

redursidae

Some sound is normal, but it shouldn't squeal, whine or be super noticeable inside the cabin with the engine running. If the noise is bothersome with the engine off (it is for me), you can set Run Valve Before Start to Off. It shouldn't cause any issues in a Miata

tfbmiata

Awesome thanks! The tone at this point you done even notice and would probably just think it sounds more like a random pump or something lighting up. I'll leave as it unless it changes. Thanks everyone!

Z_WAAAAAZ

Nice, glad it worked.

If the car will stay running with the IACV disconnected, you can simply unplug it and see if the hum disappears to rule that out. My car exhibited the same hum after installing my standalone and it ended up being the IACV. Never caused any issues though.