CustomESP

Hi Curly, I just wanted to know if you could check out my last log after updating the map. Again, there is no rush; whenever you have a minute, I appreciate all your help. I just needed to know if you felt the car was safe to drive now, as I wanted to take it to a tuner. Also can you recommend a tuner here in NJ? Thanks!

curly

iTrader: (25)

AFRs are still really ugly, and MAT is, for the third time, not reading properly. I would verify you have no leaks at the injectors, fix the mat, then drive around a bit with VEAL on easy, driving like you're on ice. Look at the cell weighting and try to hit most cells, high rpm, low rpm, high load, low load, just not a lot of boost. Then switch to normal, do it again, then to hard, and do it again. That'll start to narrow in the fuel table, but none of this can be done until the MAT is reading properly.

If you were anywhere on the west coast, there would be a few tuners including myself that I'd recommend, but sadly I don't know anyone in NJ.

sixshooter

iTrader: (12)

Buy one of these and a pressure regulator for your compressor to limit it to 20 pounds or just above whatever you're running.

https://www.siliconeintakes.com/inta...essure-tester/

Get a tire inflation chuck that clamps to the valve stem and pressurize the system and listen for leaks. There's a place for a leak at every single joint and every single vacuum line. There are two different thicknesses at least for injector seals, as well. You don't know it's a leak until you pressurize it.

sixshooter

iTrader: (12)

Check this out from my build thread

https://www.miataturbo.net/showthrea...48#post1571848

CustomESP

Thanks, Curly and Sixshooter. Do you think the MAT issue is related to me using a single hose coming from the intake manifold to feed both the Megasquirt and my boost gauge? Should I do separate hoses for both?

Also, I don't have a dedicated aftermarket MAT sensor for the Megasquirt. Do I need one?

sixshooter

iTrader: (12)

Idk what a MAT sensor is. I know Inlet air temperature (IAT) and manifold air pressure (MAP).

curly

iTrader: (25)

MAT=manifold air temp

MAP=manifold air pressure

You're thinking of the MAP sensor that has a vacuum line going to it. The MAT sensor is a 2 pin sensor in the intake tract. You may also see it called an IAT or AIT sensor. Intake Air Temp or Air Intake Temp sensor.

sixshooter

iTrader: (12)

It was always IAT to me, but I'll leave you guys to it.

curly

iTrader: (25)

MAT is just what it's called in the logs, I also typically use the IAT abbreviation.

CustomESP

Hi Curly, After stepping away for a week, I looked under the hood this morning to see if I had reconnected all the hoses from when I installed the injectors, and I found a small hose on the intake manifold that wasn't connected. I reconnected the hose, drove the car, and created a new log. Does it look like I remedied the MAT issue by reconnecting the disconnected hose? Also, I wanted to shoot you a private message/email, but I can't seem to. I'm not sure if I'm too new. Thanks again for all your help.

Jesse99James

Il'll chime in as I've been watching (not super closely). At this point I'd start to think seriously about hiring a remote tuner or finding local help. In your latest log file MAT is still way off. See for yourself, load it into MegaLogViewer and select MAT for one of the 16 graph options. You'll see it shows something like -10F to -20F. Unless you are running this thing at the north/south pole that cannot be correct. You aren't looking for a hose, you should check the wire harness wherever your intake air sensor is located.

When I found my Mazdaspeed MX-5 it had the Flyin' Miata FM2 full Garrett upgrade kit already installed (circa 2010) running on the Hydra Nemesis 2.6 ECU. My OEM IAT sensor (MAT) always read 20-30F degrees too cold so I tried the other sensor options (seem to remember the FORD calibration was fairly close). Nothing helped and I didn't feel like replacing the sensor. Instead, since Nemesis 2.6 was decade old, clunky software, I replaced it with an MS3 and decided to upgrade to a faster GM IAT sensor (open element?).

If you are sure the sensor is plugged in, I'd unplug it and run a diagnostic test using a multimeter to confirm the sensor is within specs (resistance). Once you know your sensor is good and don't see any wire harness or plug damage next verify the correct sensor is selected in TunerStudio. Under TOOLS (unlock calibrations if they are locked), select CALIBRATE THERMISTOR TABLES. Select air temp sensor and check to see if MAZDA is selected? Reread the installation/setup guide and verify it's set properly.

The ECU is reading some signal or MAT wouldn't change at all, right? You should see ambient air temp after you start a cold engine. You can also add the MAT gauge in Tunerstudio so you can watch in real time. IAT / MAT will climb and should stabilze as you drive (cruise). Mine is in the metal elbow just before the throttle body which heat soaks easily, many place the IAT in the intercooler cold side tank or pipe. If your sensor is in the intake air box next to the filter, it's only reading pre-turbo air temp. You want to monitor just before entering the engine after the turbo heats it and the intercooler cools it down somewhat. That will vary depending on many factors (boost, turbo, IC) which is why the ECU needs to know what temp air the engine is ingesting (or being force fed).

sixshooter

iTrader: (12)

That's entirely your problem, then. Either the sensor is bad, the wiring is bad (including grounding), or the wrong sensor is selected in Tuner Studio.

The GM IAT sensor is open element, so it can be ruined or effected by any number of substances (brake cleaner, carb cleaner, oil, gasoline, soap, dirt, metal shavings, metal grinding dust, etc.). IDK about the Mazda sensors.

curly

iTrader: (25)

What they all said. Not a hose, but wiring issues you're looking for.

Jesse99James

I went back and reread the entire thread. Sorry, I missed that you're working on an MSM. The sensor location is in the elbow just before the throttle body. The Mazda IAT has a solid metal body. I'm not familiar with the Little/Big Enchilada, the original owner of my MSM skipped those options for the full Garrett kit. If you have the metal intake upgrade, the IAT sensor will be located on the right side towards the engine. I think it was an M10 threaded hole. It'd be easy to miss when plugging the harness to the sensor, hopefully you'll find you only need to plug it back in.

The GM sensor I installed required cutting the OEM IAT plug off the wire harness and crimping the a new plug on. I left the two wires long enough so it can be reinstalled but I doubt that'll ever happen. I used both an angle grinder and Dremel tool to remove the OEM threaded bung, then opened up the hole slightly to fit the I.D. of the bung fitting matching the GM sensor. I found a local, custom trailer business to weld the new stainless bung onto the stainless tube. As I stated earlier, my OEM sensor was reading 20-30F too cold and it reacted more slowly than the upgraded GM sensor.

If you test the OEM sensor and it is within specs, and the plug and wire harness all the way back to the firewall look good, the next step would be to find the wiring diagram for the ECU harness and make sure that pin is ok in the OEM plug that connects to your MS3. Unfortunately, as you probably already know, access is difficult unless you are a young, flexible ectomorph (skinny). You can verify the wire harness is good from the ECU connector back to the sensor using a multimeter. First verify the correct sensor calibration in Tunerstudio, looks like you need to be connected to the ECU to see that data.

You won't be able to tune your ECU until the MAT - IAT sensor is working. :-(