Aftermarket ECU Megasquirt Install

[madkaw]

Just so you guys know I have been doing something besides being a smart arse on the forums here

I have been installing an aftermarket ECU called Megasquirt on my 71. Why you ask, because it's always been about the learning experience for me and the challenges that brings. I enjoy the L series engine and I have done the SU thing, and now the triple carb route, now I want to indulge into performance FI. Maybe-eventually-turbo charging. I am having way too much fun with the NA motor for now, and I would like to FI my L24 and save my pennies for a Rebello.

I am going to do this in baby steps so i can still enjoy my ride. This crappy winter has forced the Z indoors, but has allowed time to get one of the biggest steps started on the venture. My goal is to get the ECU wired into the car and running my ignition only. The way I am doing this I will be able to have 2 ignition systems on the car, the original dizzy and a Coil on Plug set up as well.

First things first. I bought ready to go ECU and harnesses from DIY. You can buy kits and save a few bucks, but that's more soldering then I want to do and more things to screw up. All this stuff is supported by some great forums and internet manuals to walk you thru everything--BUT--be prepared to study every chance you get. I knew nothing about FI or ECU's and bought a book by Matt Cramer that is about performance FI just to give me a staring point. Depending on your background, this could be a steep learning curve, but very doable with a basic knowledge of mechanics. If anything, this kind of project will force you to be a better mechanic or at least a more knowledgable one! I really appreciate Zfuel in his effort, now I have a better understanding of what he is trying to accomplish.

My project maybe a bit different then other that have done MS(megasquirt) in that I am starting with a 1971 model that had no existing FI attributes-a clean slate if you will. Maybe be better or worse then having a FI model. Instead of tracing down old wires and sensors, I am installing all new. Actually, I parted out a 83zxt years ago and kept the main harness and I have been picking stuff off of it for some parts of my build. Besides the initial cost of the ECU and harness, there isn't a lot of cost after that. Sensors and relays are cheap and can be swiped off of junk cars. A good soldering iron and assorted wire terminals, electrical tape and some additional wire and your ready to start. For me it took a long time just to sort out how I was going to run the wires and where to put the ECU-and study, study, study.

to be continued.....

I was going to add pics but that's not working as of now

[ktm]

Steve, congratulations on stepping into the 21st Century! You'll really want to get fueling as well since that is where MS really shines since you can tune it for all atmospheric conditions. Still, spark is the first step. When I did my L28ET conversion I opted for a different stand-alone, but putting it into a car that was not FI to begin with adds some wiring challenges.

Check out Hybridz for all of your installation questions. It's been exhaustively documented there (use forums.hybridz.org - www.hybrid.org seems to be broken).

Good luck!

[Willoughby Z]

HybridZ

I read somewhere else on the web that Hybrid Z suffered an attack on their server by executable files.

They've been rebuilding for a couple of days...

[madkaw]

Thanks Bo,

I have a thread started over there now and have been getting help.

Not many starting from ground zero, but the theory is all the same.

Yes I LOVE my Mikunis, but ready for this century grass roots motoring.

I have to finish my plenum first to get to fuel .

[LeonV]

I'm waiting for the day when I decide to convert to ITBs...

[Walter Moore]

If I had the money, I would be right there with you. I am convinced that long term FI is the path to more power and ease of operation.

[superlen]

Steve,

I don't have any experience with the MS of course, but as you're aware I've been doing a massive amount of FI research in the last several months so feel free to ping any questions off of me. I may be be able to help/give you another perspective on the theory. For the nuts & bolts of wiring up the MS, Hybridz will have a lot of peeps who have done MS on z's. They have been down for a few days. Hacked I assume.

Here's some questions/comments: (you probably know this but it's handy for others following along)

• Are you going to run just MAP or MAF? Map is simpler to install, but requires a little more effort in tuning & you have to re-tune if you change the engine airflow via cams, headers, intakes, ect.
  
• If MAF, on the Zfuel thread I have a pic of one I bought off EBAY. It's off Infinity Q45 and looks to be a good candidate. I'll know for sure by the time you get to your fueling additions. It's sized for a lot more maximum airflow that what we are going to flow so the resolution of the MS may not be good enough for this unit & a more appropriately sized one may be needed. If it were me, I'd just run MAP and forget any airflow sensor. You're hands on enough that I think you will want to go MAP as well and just tune yourself.
  
• I would use the Z stock coolant sensor as its already in the thermostat housing & you can enter the numbers into the table for it just as easy as a GM or Ford without the extra mechanical requirements of fitting it to the Z. BTW, I have some spare thermostat housings off the 75 and later FI cars if you need one for your 71.
  
• For IAT, I would use whatever is the easiest/cheapest to procure since you'll be customizing a mount for it anyway. Don't bury it in the manifold next to the block as it will suffer more from heat soak. I think the stock location on the EFI cars is pretty good. You'll just have to fab a mount.
  
• TB? Stock is simpler, but you'll have to make a mount to adapt an aftermarket analog TPS sensor onto the stock throttle body. Alternatively (and I would do it this way) is grab a TB from a 240sx. It has the TPS and IAT already on there & many have already adapted it to the stock intake. (If you don't have an extra EFI intake already, I have several PM me) Don't spend money on one of the aftermarket Big Mouth TBs. Our Z heads are going to limit airflow much more than the Big Mouth TBS & they won't add any HP. The stock diameter is adequate. The 240sx is a little bigger, but used are way less than the Big Mouths.
  
• On your 71 does it have the same round hole in the firewall under the clutch slave cylinder that the 75 & later have for the FI harness? (Not a useful question for your install, but I thought about it this morning as I was pulling a harness out of a donor car to setup for the AFM tests I'm doing for HellFire & your post timing was perfect). I'll be offering stock harnesses as well as the ECU, but didn't know if the early zs had the hole in the firewall.
  

Anyhow, keep us posted on your progress.

Lenny

[Darrel]

Depending on how far along you are, here is something that might interest you. There is someone who makes an adapter for round top su's that uses a gm injector. This could make for a stealth efi system. You can just buy the adapters and use ms or get their whole system, but it isn't as self tunable as the ms system.

Patton Machine

[superlen]

Steve,

I checked out your build...nicely done and I saw the answers to the above questions. This will be a sweet 240.

Lenny

[madkaw]

Thanks Lenny,

I'm just posting this install to give the folks here some general knowledge of aftermarket ECU and the work involved. I'm gathering you saw my thread at Hybridz-MS3X install.

Long way from yet so i might be needing some advice. Just now to the point to get my laptop to talk to my ECU.

I think what you are doing is very impressive-keep up the good work!!

[superlen]

Steve,

Yes. I took a look at your other posting after my first response here. Thanks for the Kudos on HellFire. I don't have ignition programmed yet, but my personal end goal is what you're installing now with trigger wheel, COP, IAC, ect. with a super clean smooth intake manifold.

Len

[ktm]

I personally like MAP as it is a bit easier to install and setup. You still have to return a MAF car if you change airflow too much as well (the LS1 in my 240z is MAF based), so you really won't be avoiding retuning either way.

Tuning a N/A car is also a lot easier than tuning a forced induction car in that you can safely hit your load cells if you are street tuning. You can't really (safely) do that in a forced induction car. By safely I mean both personal safety as well as engine safety.

The biggest tuning challenge you'll face is spark believe it or not. Tuning for fuel is easy if you have a wideband; you do not have a similar instrument when trying to tune spark. However, spark is not nearly as critical in an N/A car as it is one a forced induction vehicle.