49 IATwPiggy: Intake Air Temperature Sensor $9. Internal pull up on a V3. Heavy duty metal DB37 hood for superior RFI/EMI shielding (no cheap plastic ‘metalized’ hoods. 3. 5″ high. I am now running wasted spark ignition on 6 cylinder BMW M30 engine. The recall puts it towards the bell housing. 99. Hi All, I just recieved my MS3x and wiring harness yesterday, and have been looking for diagrams to use to wire it in to my car. For example, the MS3X "boost" output equivalent on the MS3-Pro is "high current out 3". Tweet. MegaSquirt MS3X Wiring Bundle – Length = 23″ ~23″ of TXL High temp automotive grade wire. We've got a pre-assembled MS3 with the MS3X extra board, and I believe it is a V3. 31. 6 engine with ITBs, COPs, MS3X 2021 Macan S Day job. This version of the documentation applies to: • MS3 on a V3. MegaSquirt MS3X Wiring Harness - 8 feet 8' of TXL High temp automotive grade wire. All that looks good, so I’m going to get a new sensor. 0 Hardware Guide 2. Note that the DIY Autotune wiring harness has a shielded wire – connect only the inner wire to this pin! Connect the E pin to pin 27. James1) MS3 Main board 15-19 grounds connected to engine block, MS3X wire harness not connected at this time. Megasquirt-3 Setting Up manual PDF WWW. 8′ MegaSquirt Wiring Harness for MS3X. 57 $ 659. Free Shipping - DIYAutoTune MS3X-Hrn with qualifying orders of $109. I have some questions as I am hooking up the wiring. 3. 2) MS3 Sensor Ground PIN 7 Not connected at this time since no TPS, IAT, Coolant, O2's are connected. There is a recall on us crankps and they sell a wiring harness kit with it. Color coded wiring with labeling printed on the wire every 6 inches -- no paper tags here! External Ignition Wiring. Would 18 gauge be alright to run from the MS. Would 18 gauge be alright to run from the MS. to the Megasquirt. All distances <. 6 > 88 Carrera wiring queries. 8′ of TXL High temp automotive grade wire. Connect the longer OEM 3-way connector to the matching LS coil connector with a green wire. Get a Quote. At least that's what the wiring diagram that came with it says. 12-30-2011, 05:07 PM #10. Note that the DIY Autotune wiring harness has a shielded wire – connect only the inner wire to this pin! Connect the E pin to MS3X pin 14 to send the timing signal to the HEI module. The MS3Pro Module is approximately 5. 57: Install a 1K resistor in the R57 slot. MegaSquirt DIYAutotune SystemsFind Wiring Harnesses 8 ft. This uses the PWM idle driver on the MS3X board. Subscribe. MS3x Wiring Questions. Note that the DIY Autotune wiring harness has a shielded wire – connect only the inner wire to this pin! Connect the E pin to MS3X pin 14 to send the timing signal to the HEI module. This harness connects to the lower (main board) connector, while the upper (MS3X) connector uses the MS3X harness. billr wrote: If it will fire while cranking, then die as soon as the key is released back to the "run" position, it seems like your primary problem is how the ignition switch is wired to provide power; probably has nothing to do with the tune. ( 7 questions) 5 out of 5 based on 6 customer ratings. Color coded wiring with labeling printed on the wire every 6 inches — no paper tags. 57 Hardware Guide 1: Introduction The MS3X/V3. Product Details. . 1. I purchased the pre-assembled MS3 with MS3X board and the 24" harness for both and pretty much have it all figured out except for these options. Ok. Wire gauge on the ms3 pro harness. 1) MS3 Main board 15-19 grounds connected to engine block, MS3X wire harness not connected at this time. 0 ratings 0% found this document useful (0 votes) 40 views. 2 Megasquirt Installation; 2. This MS3x Plug and Play setup offers much more than your standard EFI control. on the main ms3 harness there is only 1 crank input wire which I do have connected to the correct pin , everything is going to the correct pinouts according to the diagram. 1 Overview; 2. Hardware manual covering specific wiring and configuration of your Megaquirt MS2/V357 ECU. the universal Terminator X 550-937 kit is like $1070. MegaSquirt MS3X Wiring Pigtail - Length = 24" 24" of TXL High temp automotive grade wire. 5 out of 5. This Excel file details the required connections for Megasquirt 3 (MS3) and the Megasquirt 3 Extender (MS3x), using an 88 pin connector and wiring harness from either the 1992 325i (E36, Motronic 3. Starter is a new HiTorque unit. Engine Management Systems. pin 21 CLT signal. Use this high quality MS3X wiring harness to take advantage of all the great features on the MS3X expansion board. MS3base/V3. However, MS3X now has Tach output. . The 3 wire IAC driver is the only circuit there and it is not tied to any of the pins on the 55 pin connector. 0. 0 parallel install, full sequential, HPX MAF, Ford Ev6 47lb injectors, COP, custom 8 BIP373 box, E85 pump, teflon lined return style fuel system, 39 lb base fuel pressure, Twin Turbo @ 7lbs boost, Dual 4 port boost solenoids, Dual 14point7 widebands Posted January 28, 2014. Distributor Side: Harness Side: Purpose: Red: B/W: 12v+ White: G. Note that you will still need our regular MSPiggy for the main board DB37 – this is just the MS3X harness. the US Shift Pick-4 trans contoller is kinda expensive at $750 for harness and controller. 1A) internally wired to MS3 Main Connector 27 IAC1B Blue/Red . 1 ecu from bosch (Code 402) and have only been able to find wiring diagrams for the similar 3. 57 mainboard as it uses the same driver as the MS3X. Color coded wiring with labeling printed on the wire every 6 inches -- no paper tags here! All wiring is pre-crimped (NOT solder cupped!) to the DB37 Heavy d. In step 22, install the stepper IAC jumpers (all of our assembled MS3 units are by default configured this way). I've tried each wire from the sensor. by Dennis930 » Fri Jul 30, 2010 1:56 am. For a V3. 57 Hardware Manual Megasquirt-3 Product Range MS3 1. To start viewing messages, select the forum that you want to visit from the. Color coded wiring with labeling printed on the wire every 6 inches -- no paper tags here! Use with MS3X Expansion board or other sequential device Just. MS3X is designed to run logic "smart" coils specifically like the LSx types which are usually 4 or more wires. 57 mainboard as it uses the same driver as the MS3X. MS3x Wiring Questions. MegaSquirt MS3X Wiring Bundle – 23″ 5 out of 5 $ 29. Internal pull up: For a V3. 8′ MegaSquirt Wiring Harness for MS3X. SAYS IF HALL SENSOR. MS3X/V3. 1A) internally wired to MS3 Main Connector 27 IAC1B Blue/Red . Notably, the car features a BMW E46 M3 6-speed transmission, a Thayer Motorsport upgraded Limited Slip differential, and a meticulously assembled engine. Does the DIY MS3 wiring harness have wires populated for these pins? (Pins 5-6 on the MS3 output). I even pulled the Ms out and made sure the jumper was installed for the cam input. Beach, VA MS3x Wiring Questions by Dennis930 » Fri Jul 30, 2010 1:56 am I installed a MS3 cable harness when I installed MSII last year. I have a couple questions I have some resistors to be able to run TFI as well as the ms3x card so I can easily run my PWM IAC and my A/C. MS3Pro EVO Standalone Engine Management System w/ Harness. Then I checked from the bulkhead to the Ms, that was good. Anyone onto the questions. Checking my COP wiring with my timing light, it seems that the coil output from MS3x needs to be wired in the following manner. SAYS IF HALL SENSOR. MegaSquirt 3 ECU with MS3X Expansion. MegaSquirt Wiring Harness - 8 Feet Long We've completely redesigned our wire harness to help you get your fuel injection installation right the first time with several new features to help make your installation as easy and reliable as possible:. ~23″ of TXL High temp automotive grade wire. MS3base/V3. Hardware. Well at this point between the wiring. Post by Bahooki » Thu Feb 01, 2018 5:39 pm. (no paper tags). HOWEVER when using the test page it seems that I am STILL not getting any spark signal from the. 1A) internally wired to MS3 Main Connector 27 IAC1B Blue/Red . 99. I've also tried the nitrous in. We’ve got your MS3Pro ECU with drop-on/PNP LS Wiring Harness, ready to make the job EASY! News & Updates Read More. Just like the MS3X harness, but with no DB37 connector. Re: MS3 knock sensor wiring question. MegaSquirt MS3X Wiring Harness for full sequential fuel injection and ignition, as well as tons of other I/O (Dual Stage Nitrous, 2nd O2 Sensor, Boost/Launch Control, etc)This is the harness build guide for the Megasquirt MS3X. x card will need to be able to manage a 1992 f150 4wd 351w with MAP efi? also i see diyauto tune sells wires for the ms wiring harness that is 20 gauge. 5 out of 5 $ 114. i know i have 4 extra fuel/spark wires. 0pcb. For bench test purposes I have set the PWM idle duty table to 50% at the current temp. SAYS IF HALL SENSOR. Found it relatively cheaply at 4K. All wires are color coded and printed with their functions. Long TXL High-temp Wire, Heavy-duty DB37 Metal Hood, RFI/EMI Shielding, for use with MS3X Expansion Board, Each Location: Sandefjord, Norway. The BMW E36 is a masterpiece of attention to detail. 0 MicroSquirt with 30″ Harness is an entry-level, fully assembled ECU and universal 30″ pigtail with varied applications targeting power sports, single cylinder all the way up to 8 cylinders. 4 Scope of advice with MS3X; 2: Megasquirt System Hardware. 70 Subtotal without wideband . 1-8 Spark 1-8 Cam Nitrous 1 (Line Lock) Nitrous 2 (Trans Brake) Boost (Boost Solenoid) EXT_Map (LS9 Map Sensor). I beleive it is 10G wiring to the controller (18g pwm wire) and 12-14G out to each fan. I'm in the process of installing MS3X in my 1994 Mercedes SL600 which uses the M120 V12 engine. To start viewing messages, select the forum that you want to visit from the selection below. Today's Posts; Member List; Calendar; Forum; Saturn Related Forums; Saturn Performance; Tuning / Fuel Management; If this is your first visit, be sure to check out the FAQ by clicking the link above. Everything on the jimstim works too except the rpm signal. Color coded wiring. Color coded wiring with labeling printed on the wire every 6 inches — no paper tags here! Use with MS3X Expansion. Not Yet Reviewed. Anyone onto the questions. 8′ MegaSquirt Wiring Harness for MS3X. 57 mainboard as shown above running firmware MS2/Extra 3. We've got a pre-assembled MS3 with the MS3X extra board, and I believe it is a V3. If someone with more experience could look over my setup I'd be ecstatic. 3) MS3 Cam Input (Dual VR v2. General Tech Forums. 1 Overview; 2. My original thought was that the only thing that could have change could have been wiring from jostling the harnesses around. Share. I have a couple questions I have some resistors to be able to run TFI as well as the ms3x card so I can easily run my PWM IAC and my A/C. DIYAutoTune Wiring Harnesses MS3X-Hrn. 4g63 with stock 1990 sensor. Am I missing it or is there a color code key for the ms3x harness. now can i use the spare 4 fuel or. 2 digital outputs. input wired with a 5v pullup. If that's the case how can I change the inputs; From what I understood I would just unhook the 2 ignition wires from the db37 harness and run it into my ms3x expansion harness under SPARK A and SPARK B. . The R pin is the HEI module’s tach output. 1 ecu that is the vanos motor. 3. 57 mainboard with MS3X as shown above running firmware MS3 1. Getting closer to having a completed MS3x wiring harness on the turbo mustang. 99. You can use it with OEM harnesses or wiring from other sources, and use it with any ECU. 0 Hardware Guide 1:Introduction The MS3X/V3. The versatile MicroSquirt with 30″ Harness: Standalone Engine Management System, Transmission Controller or CAN I/O Expansion Module- Version 3. x card will need to be able to manage a 1992 f150 4wd 351w with MAP efi? also i see diyauto tune sells wires for the ms wiring harness that is 20 gauge. 4. I have wired in pull up resistors in the wiring for both so the MS3 gets a voltage it can process. I have a couple questions I have some resistors to be able to run TFI as well as the ms3x card so I can easily run my PWM IAC and my A/C. 6 Bench Test Wiring: MS3X/V3. 1A) internally wired to MS3 Main Connector 27 IAC1B Blue/Red . 82 - 83 280zx Turbo distributor wiring plug. Wiring the engine harness to the MS harness has been pretty clear except for some uncertainties with the CKP input and what our setup is capable of. I am also using the MS3X to drive my injectors and pin 36 on my mainboard harness only switches my CDI on and off for ignition so my mainboard harness doesn't really need to. Learn how to set up and tune your MS3X/V3. MS3 code uses a somewhat different wiring pattern for the MS3X outputs. MegaSquirt MS3X Wiring Harness - 8 feet 8' of TXL High temp automotive grade wire. External Ignition Wiring. Which outputs (A,B,C and D) go to. 57 is an ECU based on Megasquirt-3 technology, consisting internally of an MS3 card and an MS3X expansion card installed on a surface mount V3. I did a MS3x install last winter and used DIY's 10' wiring harnesses. Wire spark output A (MS3X pin 14) to the stock ignition module trigger wire. To pin 30, connect the 12 gauge red wire you ran all the way to the fuel pump. At least that's what the wiring diagram that came with it says. And also while cranking. SAYS IF HALL SENSOR. by 87ponygt » Wed Dec 30, 2015 3:22 pm. 0, solder a 1K resistor to a length of wire and run it from the 5 volt point in the proto area to the TachSelect-VRIN jumper. 3) MS3 Cam Input (Dual VR v2. Find DIYAutoTune MegaSquirt MS3X Wiring Harnesses and get Free Shipping on Orders Over $109 at Summit Racing! DIYAutoTune MegaSquirt MS3X wiring harnesses are 8 feet of TXL high-temp automotive grade wire. Using FIDLE and Idle will certainly be ok with the V3. 00. Get Connected. 99. MS3X Cam VR wiring. Shop for the best Fuel Rail Pressure Sensor Connector for your vehicle, and you can place your. yes i was aware of the pin number being incorrect when i was installing the harness. 8′ MegaSquirt Wiring Harness for MS3X. MS3X setup and comm issues. But my big brain figured to follow MS3x directions and redo the wiring harness. They feature color-coded wiring with labeling printed on the wire every 6 in. The MS3 case is like a 2 1/2" high version of a regular V3. 99. MS3Pro Ultimate Configurable Inputs/ Outputs: 10 channel 4:1 or 8:2 programmable peak and hold injector outputs. #32. Includes complete Universal 8′ Flying Lead Harness. 1. I am also using the MS3X to drive my injectors and pin 36 on my mainboard harness only switches my CDI on and off for ignition so my mainboard harness doesn't really need to sink alot of. Where is this harness made? We assemble this harness in Gainesville, Georgia, USA. Powers all the injectors. And used MS harness wire #30 to control the IAC valve. The MS3X also uses a similar VR conditioner for its cam input circuit that adjusts in the same way. 57 mainboard. The setup is a LQ9 408 so i have the harness occupied as follows so far: Main Board: IAT CLT TPS Crank EGO1 (Innovate Bank 1) INJ. ) 5. Add to cart. Beyond the Ordinary: BMW Style with a 2J Twist November 14, 2023 Read More . Joined: Mon Sep 19, 2011 6:10 pm. See the MS3 manual wiring diagram for how to wire it up. 2. I have a couple questions I have some resistors to be able to run TFI as well as the ms3x card so I can easily run my PWM IAC and my A/C. This terminal is also grounded to the engine block. Would 18 gauge be alright to run from the MS. 0 parallel install, full sequential, HPX MAF, Ford Ev6 47lb injectors, COP, custom 8 BIP373 box, E85 pump, teflon lined return style fuel system, 39 lb base fuel pressure, Twin Turbo @ 7lbs boost, Dual 4 port boost solenoids, Dual 14point7 widebandsPosted January 28, 2014. 8′ MegaSquirt Wiring Harness for MS3X. MS3 wiring harness colours - standardisation. 3. For input I've tried datalog in, tableswitch, and the other ground switching input that I can't recall at the moment. I'm using 2 shielded 22AWG stranded 2 conductor wires for the CAS, and I'm not quite sure how I should route the 'cam' wire. The heart of the beast! A turbocharged 2JZ dancing to the tune of an MS3X ECU. From the factory it had the sensor mounted to the timing cover. They feature color-coded wiring with labeling printed on the wire every 6 in. 2) MS3 Sensor Ground PIN 7 Not connected at this time since no TPS, IAT, Coolant, O2's are connected. DB37 Solder Cup Connector for MS3X $ 8. 1 PWM IAC output – can be repurposed as. SKU: MS3X-Hrn Categories: MegaSquirt 3, MegaSquirt 3, Wiring Harnesses & Wire Bundles Tags: 3, 357, harness, iii, mega, megasquirt, megasquirt3, ms3, ms3x, squirt, wire, wiring Brand. MS3 Pro Plug and Play for 04-05 Mazda Miata Mazdaspeed Miata. 2) MS3 Sensor Ground PIN 7 Not connected at this time since no TPS, IAT, Coolant, O2's are connected. I am using the Megasquirt 3 with MS3X expansion. Matt Cramer -1966 Dodge Dart slant six running on MS3X. Megasquirt diagram wiring ms3x ms3 computer honda efi engine wire fuel source iq installation injection [diagram] megasquirt relay board diagram20 beautiful megasquirt wiring diagram Megasquirt relay board harness did own adRelay board mod: 2-wire pwm air valve + electric fan relay. recently I purchased new MS & MS3X wire harnesses from DIYAUTOTUNE. 0 too, but the point gurov makes is fair - using identical drivers for both sides is good practice. Soo its been a min 😅. 1998-2002 GM LS1 / LS6 Drive by Cable EFI Wiring Harness HAR-1012 LS1 Harness Instructions. COP setup. I have a couple questions I have some resistors to be able to run TFI as well as the ms3x card so I can easily run my PWM IAC and my A/C. Part Number: BEC1800715. Color coded wiring with labeling printed on the wire every 6 inches — no paper tags here! All wiring is pre-crimped (NOT solder cupped!) to the DB37. Wiring Harness, MegaSquirt, 8 ft. That’s it! Using the. 1 ecu that is the vanos motor. I bought a de-pin tool so I can repin my DIY harness and have done it exactly as shown in the first diagram (ms3x) - with each sensor getting a ground wire. Our USA-assembled map sensor uses a universal keying that is compatible with pigtails for 1, 2, and 3 bar MAP sensors. MegaSquirt Wiring Harness - 8 Feet Long We've completely redesigned our wire harness to help you get your fuel injection installation right the first time with several new features to help make your installation as easy and reliable as possible:. It's a bitch reading the spark wires. . There are 3 or 4 MS side harnesses that are about 14" long, they all come from the MS3X pigtails and go to those gray multiplugs. Connect the 12 gauge red fan power wire to a spare terminal on the fuse. SAYS IF HALL SENSOR. Wiring the engine harness to the MS harness has been pretty clear except for some uncertainties with the CKP input and what our setup is capable of. ( 7 questions) 5 out of 5 based on 6 customer ratings. 5 4. Would 18 gauge be alright to run from the MS. 57 is a little. 5bar map built into the MS unit. Ms3x forums Megasquirt wire executing experiment mega ii plan part Ms3 and ms3x wiring questions Megasquirt ms3x wiring diagram. The MS3X/V3. 3) MS3 Cam Input (Dual VR v2. Notably, the car features a BMW E46 M3 6-speed transmission, a Thayer Motorsport upgraded Limited Slip differential, and a meticulously assembled engine. MegaSquirt MS3X Wiring Harness – 8 feet 8′ of TXL High temp automotive grade wire. MS3 – Fully assembled and tested, ready to wire in and go! The MegaSquirt 3 (MS3) is ready to support a wide variety of engines out of the box, with the ability to control anything with one to eight cylinders with sequential fuel injection and sequential ‘coil on plug’ ignition, a V12 with semi-sequential fuel and wasted spark ignition, or a four rotor Wankel with separate. I probed the wiring harness and had continuity between pin 2 and the corresponding pin on the VR connector, so the screen appears to be connected. On the MS3X expansion board, R11 adjusts the threshold voltage, and R32 adjusts the hysteresis level. Well, apparently I’m not too brave lol. Color coded wiring. 3) MS3 Cam Input (Dual VR v2. The recall puts it towards the bell housing. MegaSquirt-I Relay Cable (if you’re using the relay board and cable, you don’t need the standard MSHarness12, see note in product description)We carry 8′ wiring harnesses for $83 that are designed to be adapted to any engine. 99. I'm currently working on the MS3 hardware manuals and as I've arrived at the table of wiring connections it has become obvious that the different existing manuals show different wire colours. 1A) internally wired to MS3 Main Connector 27 IAC1B Blue/Red . The crank position input, is has the red wire from point 25 meeting the black from point 8 and then connecting to a blue and yellow wire at the pigtail. 00 MS3X-Hrn: 8' MS3X wiring harness $22. I purchased an aftermarket harness for it and that wiring was smaller. I am hoping to test fire my car this week. (Speed Density only. I have a MS3 with expansion board MS3X. Post by shiftin04 » Thu Jul 08, 2021 3:06 pm. Otherwise when current flows through the grounds, there is a potential developed and the "ground" on the cam sensor will be below the ground on the Megasquirt. MegaSquirt MS3X Wiring Harness - 8 feet 8' of TXL High temp automotive grade wire. MegaSquirt Relay Cable. 3 high current digital/pwm outputs. On a V3. x card will need to be able to manage a 1992 f150 4wd 351w with MAP efi? also i see diyauto tune sells wires for the ms wiring harness that is 20 gauge. Hey Everyone. x See the Setting Up manual for more detail on version numbers. Megasquirt diagram wiring ms3x ms3 computer honda efi engine wire fuel source iq installation injection [diagram] megasquirt relay board diagram20 beautiful megasquirt wiring diagram Megasquirt relay board harness did own adRelay board mod: 2-wire pwm air valve + electric fan relay. 57 case, making it significantly taller than the DIYPNP case. Skip to content. 0 MicroSquirt with 30″ Harness is an entry-level, fully assembled ECU and universal 30″ pigtail with varied applications targeting power sports, single cylinder all the way up to 8 cylinders. 1 Cowl Wiring Harness CM-14A006-A5LB This harness is labeled and includes all connections required to power up and run your engine equipped with a 2011 or newer. 2003 Mustang 2V stock harness splice, MS3X v3. From that same relay area, run a 12 gauge red wire all the way back to the ECU. Posts: 70. 2) MS3 Sensor Ground PIN 7 Not connected at this time since no TPS, IAT, Coolant, O2's are connected. During installation I added the wire from S12 to C end of D1 on the MS3X card per page 231/2. 3. We’ve packaged a DB37 male solder cup connector and a metalized plastic backshell for your MS3X builds. Add to cartToday's Posts; Member List; Calendar; Forum; E30 Technical Forums; General Technical; If this is your first visit, be sure to check out the FAQ by clicking the link above. I will include an MS3X and MS3-Pro wiring diagram and put MS3-Pro equivalents in brackets when referring to MS3X wire names and pin numbers. I connected the "signal" grounds to the terminal where I ground all of the megasquirt grounds. 1A) internally wired to MS3 Main Connector 27 IAC1B Blue/Red . And all this is taking more than I had planned. The extra wire in the shielded cable that should be in Pn #2 on the hardware guide just seems to have been spliced into one of the chassis grounds. HOWEVER when using the test page it seems that I am STILL not getting any spark signal from the. g. MegaSquirt MS3X Wiring Harness – 8 feet8′ of TXL High temp automotive grade wire. MS3x first power up, signal and wiring check. Alot of time the shield wire of the crank wiring is left untouched, but it needs to be grounded. SAYS IF HALL SENSOR. To make sure you can’t accidentally switch the upper and lower harnesses, the MS3X harness uses a male DB37 connector instead of a female one. SAYS IF HALL SENSOR. 7. Add to cart. 1L Hemi along with the engine wiring harness off of Craigslist. VISIT US. I am getting ready to purchase a MS3X Kit, I just wanted to get anyone's ideas of anything I have missed. 0 PCB, everything in the standard Bill Of Materials, the MS3 daughter board kit, the case, pre-machined endplates and heatsink bar. Depending on your fan, this may or may not be adequate. 8′ MegaSquirt Wiring Harness for MS3X. MegaSquirt MS3X Wiring Harness - 8 feet 8' of TXL High temp automotive grade wire. . Uploaded by Ojeda Orlando. For those wanting a complete, ready-to-go setup with harness, calibrations, etc then look at the. ( 8 customer reviews) $ 1,749. x card will need to be able to manage a 1992 f150 4wd 351w with MAP efi? also i see diyauto tune sells wires for the ms wiring harness that is 20 gauge. I get to installing the MS3X. RX7 Series 2 13B Turbo. SAYS IF HALL SENSOR. Connect it to pin 24 on the Megasquirt, or the Tach pin on the relay board. 0 engine in my 1988 Mustang that had a 4 cylinder previously. To make sure you can’t accidentally switch the upper and lower harnesses, the MS3X harness uses a male DB37 connector instead of a female one. Would 18 gauge be alright to run from the MS. 57 – The MegaSquirt 3 is a drop in daughter card that greatly expands the MegaSquirt’s functionality. MegaSquirt wiring harness, Innovate Motorsports LC-1, and LM-1 Wideband O2 Sensor systems and gauges, and ignition.