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10′ MegaSquirt Wiring Harness (MS1/MS2/MS3 Ready)
10′ MegaSquirt Wiring Harness (MS1/MS2/MS3 Ready)
10′ MegaSquirt Wiring Harness (MS1/MS2/MS3 Ready)
10′ MegaSquirt Wiring Harness (MS1/MS2/MS3 Ready)
10′ MegaSquirt Wiring Harness (MS1/MS2/MS3 Ready)
10′ MegaSquirt Wiring Harness (MS1/MS2/MS3 Ready)

8′ MegaSquirt Wiring Harness (MS1/MS2/MS3 Ready)

5.00 out of 5 based on 3 customer ratings
(3 customer reviews )


In stock


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:

  • We use a custom made twisted pair cable with a foil shield for ignition input, for maximum noise suppression.
  • Thumbscrews make it easier to tighten down in spots where you can’t easily fit a screwdriver.
  • Wires for pins 3 through 6 have been added for CANBUS or extra I/O.
  • Your choice of 2′ or 10′ lengths  (see MSPiggy short harness)
  • Injector wires use two smaller wires instead of combining two pins into one large wire, reducing the number of splices needed in your harness.
  • Wires are printed with both their function and their pin number.
  • Dedicated sensor ground wire.

And, of course, we’ve kept the features you’d expect from one of our wiring harnesses:

  • IAC and Ignition wire have been added for MS-I / MS-2 use or MS-3 Primary Harness Use
  • 8′ of TXL High temp automotive grade wire.
  • Color coded wiring with labeling printed on the wire every 5 inches — no paper tags here!
  • All wiring is pre-crimped (NOT solder cupped!) to the DB37
  • Heavy duty metal DB37 hood for superior RFI/EMI shielding (no cheap plastic ‘metalized’ hoods used on our harnesses)
  • Wiring diagram included
  • Simply the best MegaSquirt harness available anywhere, at any price

Note: The Wiring Harness and Relay Cable are ‘mutually exclusive’, meaning they are not designed to be used together. If you are using the wiring harness then you are wiring everything directly back to the DB37 on the ECU with relays and fuses where needed. If you are using the Relay Cable you are connecting the DB37 on the ECU to the Relay Board directly (so there is nowhere to plug the harness in anymore) and you then wire everything directly to the screw terminals on the relay board. Our Wiring Bundle comes in handy for installation with a Relay Board.

Customers' review

Rated 5.00 out of 5 stars
3 reviews
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3 reviews for 8′ MegaSquirt Wiring Harness (MS1/MS2/MS3 Ready)

  1. 5 out of 5

    Quality loomit came rolled in a neat lil brown box with a nice diyautotune sticker
    has that original premium feel to it everything is sturdy
    wires were labeled in black except ground which was black just in case you couldn't figure it out
    some wires are just a TAD hard to read

    if i was to change anything to this dam near perfect loom it would be to add a pin number to each for easy identification

    Was this review helpful to you? 4 of 4 people found this review helpful

  2. 5 out of 5

    This is so superior to anything available from MS suppliers in my country (they supply all wires in the same guage and colour, with paper labels) and delivery was exceptionally quick. This is loom form Diyautotune is designed to make your installation logical and easy, there is no good reason not to buy either this or the shorter 24" one. Good tools let you focus on the job at hand instead of diverting energy to making the tools work for you!

    Was this review helpful to you? 3 of 3 people found this review helpful

  3. 5 out of 5

    The 8' wiring loom is excellent especially if u are splicing into the existing vehicle harness, all the wires are labeled in varying segments, only downside is that on the brighter coloured wires, they used white ink rather than black, so it is a bit harder to read, but overall is a great product that is well presented :)

    Was this review helpful to you? 3 of 4 people found this review helpful

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What sort of wire do you use in this harness?

  • We use 20 gauge high temperature, automotive grade TXL wire.

Are all the pins populated?

  • We populate all the pins except for some of the ground pins. The main board does not require using all the grounds. See our MegaSquirt grounding page for more information.

If I am using an MS3 with MS3X, do I use this harness or the MS3X harness?

  • The MS3 with MS3X has two DB37 connectors, each of which use a harness. This harness connects to the lower (main board) connector, while the upper (MS3X) connector uses the MS3X harness.

Where is this harness made?

  • We assemble this harness in Gainesville, Georgia, USA.

Questions & Answers

  1. 0 votes
  2. 0 votes

    The harness has the MegaSquirt connector on one end and the other end unterminated - it's what is known as a flying lead harness in the aftermarket EFI industry. You can source the connectors needed to complete the harness from the wiring components section of our website, a junkyard harness, or specialty connector sites.