Question about megasquirt

[1984533i]

I have a 84 533 that I'm gonna be putting a 745 turbo on and I have a 745 harness and ecu but it's not 55 pin motronic . I'm confused on which megasquirt kit to buy and do I need a 55 pin harness

[turbodan]

The 55 pin harness requires less modification but you can make just about anything work.

[Jeremy]

You're going to be reading wiring diagrams and modifying the wiring no matter which route you take.

[Xenocide]

I updated to the 55 pin (super eta) harness, and I sort of wish I had kept my old 1.0 harness. I made a little adapter harness which worked great. You'll have to run another shielded line for the new crank sensor, but it's very straightforward and the diagrams are good and easy to find. I sacrificed a dead computer power supply for the wire, but you can buy a bundle of labeled wire from diyautotune for not much money at all now.

The goathumper adapter boards are nice, but there are several different versions and the documentation is spotty to say the least. I had half a mind to just make my own PCB when I was trying to get mine going.

[GI jonas]

Get a 55 pin harness and buy the MS pnp.Nothing about MS is easy but this will at least make it EASIER.

[alijonny]

MS...EASIER.

[Brad D.]

I'm also of the 55 pin ecm school of thought.
you need to do more than just the harness though. You will need to swap balancers, add the front mag pickup, add circuitry for an IAT sensor, etc. Unfortunately MS isn't for the faint of heart.

[Nebraska_e28]

I think it took me around 3 weeks start to finish to build my MS. This included everything from soup to nuts. I literally studied Brad D.'s info in the FAQs until I had a firm grasp on everything & even then asked several questions on things I was unsure about. Not to mention it also helped seeing Brad's setup in person & picking his brain some years back. I suggest you print off the schematics & think the whole thing through in order to ensure you've accomodated for any possible upgrades you may want in the future. Building MS from scratch definitely give new light to understanding how everything plays together in addition to gaining experience in how to go about troubleshooting things should something go awry later down the road.

[ianwood]

I am part way through the MS learning curve now. It's a bit like drinking from a firehose and can be pretty overwhelming at first. But it does start to make sense. As for harness, the 55 pin harness and DIYPNP (oxymoron?) version of MS might be your best bet. As mentioned, you'll still need to wire the VR sensor and IAT sensor. If you go for more of the advanced options like multiple coils (wasted spark) or sequential injection then you'll need additional wiring. I ditched the stock harness completely and used the DIYAutotune harness but that was mostly because the stock harness was brittle and beaten up. Speak to Matt Cramer at DIYAutotune and he should be able to give you some advice about what you will need. Note that there are some changes (jumpers, etc) that are required on the MS board itself depending on your configuration, so talk to Matt about that as well before you order anything.