96Formula6spd

Hey guys, I am working on putting a ms3 with a break out box into our lemons car. I had a few questions. This is the first time with my own megasquirt but not the first time around them. Starting to read more in what I need to do for setup. Right now working on cleaning up the break out box by re doing it all. Was not a fan of the previous guys work.

First off I have a 1.6 Auto throttle body with the 4 pin tps. If I swap this in what do I need to do wiring wise. I know the manual one is an on off switch and the ms3 will be happy with a variable tps. Should I use the auto throttle body or should we go with an adapter and a bmw tps. What do you guys like to use.

Second I am going to get a aem wideband for the car. When wiring this in does it go to the break out box or should it go straight to another part of the harness coming out of the basic ms3 box harness.

Third. Going to get the speedyefi harness that adapts the afm box to just the iat sensor. I am also getting their fuel pump jumper. For a 1.6 is there anything else I need to do?

Probably will have a few more questions as I start working. Dyno day is near the end of August so we have a few weeks to get everything together and get it running.

drakec9

Hey Formula, having recently built a 1.6 miata i would like to try to point you in the right direction with your build. Regarding your first concern about the vTPS, I personally use the BMW sensor conversion from Flyin Miata. The install is super easy, you do however have to flip the two outside wires on the connector that plugs into the TPS. I do not remember the color of the wires but it is a 3 pin connector and you simply swap the connections on the outside and leave the middle wire alone. I do no have experience with any other variable TPS solutions.
Your second concern refers to the wideband wiring, I personally use an Innovate gauge with a bosch sensor, the AEM gauge wiring will be different than my own but I do remember there being a second output wire for my unit. I only use the main output and wired it straight into the factory harness where the old o2 sensor connector is under the coil packs. The second output could probably be used for a breakout box like in your situation but as i mentioned i do not use AEM so you may need to look in the instruction manual for help.
Lastly I believe youve covered everything to get your 1.6 car ready for MS3 but do not forget to remove the ST Sign fuse from the passenger side fuse box. This is a MUST on 1.6 chassis when installing Megasquirt and will be listed in the install instructions for MS3.
I hope i could help!

x_25

I run no vTPS and just use MAPDot for AE on my 1.6. Did that to get it running and testing and never found the need to put in a TPS (someday I will....).

For the AEM, I snipped a wire off an old single wire O2 sensor and just wired the output of the wideband to that. The UEGO can simulate a narrow band if you ever have to put the stock ECU back in.

Otherwise sounds like you have it covered.

96Formula6spd

Alright, Sounds easy enough with the oxygen sensor.

Still split on the TPS. Might just go with the bmw setup. Plus our auto throttle body has seemed to gone missing.

Good news I pulled the ms3 apart and and found a ms3x expansion board. So the second round of questions is what should I run out of the ms3x board and what should I run out of the regular ms3. Going to see how the last guy wired it up. But redoing the solder work at the break out box. Going to keep the car batch fire and batch fuel injection. Keeping the stock wiring harness for now.

drakec9

The regular ms3 will run everything you need for your build. I do not have an expansion board and am still able to run flat shift and sequential fuel injection(which I will add is very easy to do with great benefit). The expansion board adds a ton of room for goodies such as 8 sequential fuel injection outputs, 5 or 6 medium current outputs, and various switched and analog inputs. So the board basically allows you to use features that most of us do not need or use for daily driving with the monthly track day.

Matthew Roberts

I just put an MSPNP2 on my N/A 1990 build. The builder of my MS recommended the SpeedyEFI vTPS kit. Its truly plug & play, and I think a bit cheaper than FM.

96Formula6spd

Yeah however its 3d printed and I have seen two of them melt enough from engine bay heat that they shift. Buddies personal car did that and he swapped to a metal unit. Being this race cars first date with the ecu is a full 24 hour race stuff is going to get hot.

96Formula6spd

I have thought about doing sequential fuel injection. But starting to hit a wall with getting the car done. down to six weeks to go before our next race. Really wanting the stock wiring there in case we have an issue. This way the stock ecu could go back in. This could happen later on down the road but for now its staying batch fire injection. That being said what all does it take to change over. I figure its some extra wiring to the injector harness.

The engine is a fresh garage build 1.6. I hand ported the head and intake. We lapped the valves. Bottom end is stock bore. Has a riceland header and a home built intake. Rest of the exhaust is left over home built stuff from autox days. This car has been mostly a junkyard build. All the suspension mods have lkq paint on them. Even the torsen came from lkq.

drakec9

Sounds sick you should post some pictures for us! The stock injector harness disconnects from the main engine harness; this subharness also has the coolant temperature sensor. In stock wiring format, the ecu uses two injector drivers to power 4 injectors. 1-3 and 2-4 are paired and fire at the same time always. To convert to sequential you will be essentially wiring two of these injector wires into the options port or in your case the MSX board to the supplied extra injector drivers. You must remember the firing order is 1342 because in the wiring diagram matches letters to the injector drivers, injector driver C is injector 3 and should be wired as such etc. So in my built I have cut the yellow wires for injectors 2 and 3 and wired them straight to my MS2 via the options port. MS3 will have a jumper on the main board of the ecu that will need to be on the correct pins for sequential fuel injection as well as fuel settings in tunerstudios will need to be changed.

96Formula6spd

Yeah might just leave it batch fire injection for now. Making most things plug and play in case we have an issue. This way the stock ecu can get slapped in and run. Nothing like lost laps. You can watch a 2 or 3 lap lead fall in 6 minutes. As for the car here are a few pictures over the years.

Night Race. First race with the car last year.




Last years fall race.


Now with some wider wheels. No more 15x6. We got 15x7 to make more use of the 225/45/15 RS4. Still has the tire doughnut from its first race.


Buddies instagram from barber. The rebuilt engine sounds very healthy.


And one last one. Our old race car which needs to make a return....as its just a big miata. Really this car is a blast to drive. Just think it if had more than 150hp and an engine that did not smoke. Last 14 hour race it used two gallons of oil from the blow by.



Really it smokes. But it ran the whole race and won class C. We got the $600 in Nickels to prove it.

Matthew Roberts

Yikes. Hadn't heard that...guess I'll add the FM bracket, then...

96Formula6spd

Yeah I think he has a metal on in the works. Buddy was not the only one complaining