Anyone know where to wire the sensor wire for a GM flex fuel sensor on a DIY autotune MS3Pro PNP? Seems like it's supposed to go on digital in 1, which can be either flex or clutch switch. I also have a rear options plug which has a pin for "clutch sensor." I do not have a 22 pin "option harness" that the miata megasquirt manual talks about on the megasquirtpnp page.

 

No experience here, but I have been reviewing MS3 documentation for the past few months. The MS3 pro pnp documentation provided on the diy website indicates pin 2H digital in 1 (flex), like you mention. Also pin M on the rear options connector. Turner studio only seems to only allow that pin for flex, no other options in the dropdown

 

MS3pro is proprietary to DIYAutotune. Megasquirt manuals might be quite misleading. Email their tech support for the best advice.

But as Houleo wrote above, the documentation says to utilize digital switched in 1. Excerpt from manual:

Flex Fuel:
Instead of launch control, the Digital Switched In 1 input pin of the option connector may be connected to a GM flex fuel sensor. To enable this, go to Fuel Setup -> Flex Fuel Sensor. Enable flex fuel and set the sensor port to Digital Switched In 1. The frequency numbers are set up for a stock GM (or Ford Taurus) fuel composition sensor. The low frequency represents the sensor output with pure gasoline, and the high frequency represents pure ethanol. The MSPNP Pro will multiply the pulse width by the Fuel Multiplier % number determined by the measured fuel compensation, and add the Timing Addition value. the timing.

 

Thanks for the input. I should have mentioned that my car is an 03. The digital in 1 is not listed on the mspnp manual for my year. Pin “m” seems to be digital in 1 in all previous (pre 01-05) manuals. In mine, it is digital 2. However, “pin n” is labeled clutch signal. This corresponds with the digital in 1 from the second table that Attached. I guess pin N must be what I use for my car.

 

the base tune from diy for the 01-05 model years still shows digital switched in 1 as the flex fuel pin. As hector suggested you should email their technical support to verify which pin to use.

 

thanks, but I figured it out through the help of someone on the mega squirt Miata Facebook group. It needs to be pin 4I of the 31 pin oem connector. This is the clutch switch wire on the harness.

 

Hey there! I know this is an old post but I am looking to connect my flex sensor on my '01. I have come to the conclusion from my research that 4I on the OEM harness is where I need to tap in at, I found this post and I wanted to confirm what year you had and if this had worked for you.

Thanks Bud!

 

ran into this same issue trying to add flex fuel into a 05 miata running MS3, i found that the instructions from AMP engine managment are incorrect for installing this as well as I reached out to them directly and also got incorrect information.
confirmed it is pin 4I green w/ white wire, for the clutch switch, you will have to re-wire your clutch switch to you options port on the MS if you want to keep you clutch switch for launch controll or FFL.

 

Could you not add it to K (digital freq in 3) or L (digital freq in 2) on the options port, then change the sensor port in the drop down to the digital freq in 3 or digital freq in 2 option? If you HAVE to use the clutch safety switch BECAUSE it is in digial freq 1 and then you have to rewire the clutch, it doesn't sound really PNP if you are snipping the OEM wires.

I am planning on running the GM flex fuel sensor this way. Pull 12v from the fuse box on the passenger side, ground wire to MS ground, and sensor wire to K or L.

Now to add a question on to a question, the GM Flex Fuel sensor also does fuel temperature. Is there a way to see that in Tunerstudio?

 

The only supported input for a flex sensor is digital switched 1, according to DIYAutotune. You can try and put it to some other input and report back if it works out but I don't believe it will.

The fuel temp parameters can be set-up just like the ethanol content parameters.