Harness and Ecu?

[Dinosport]

I have an ly6 I'm gathering parts for to drop into my 79Malibu. Aside some little things my next major concern is induction. If I go EFI I'll need a harness and ecu. I know a guy with 6.0 that has a harness and ecu he won't need plus Running a search on eBay I found harness ecu and pedal for 350. I know the older ecu's will be looking for a 24tooth recuctor and I believe a different voltage signal. I've seen there an adaptor for that which changes the signal so one can use a newer motor in an old Silverado or something. So I'm not really to concerned with that.
Anyway down to the nitty gritty. I will be camming the motor and eliminating the Vvt, valve springs, and possibly the trunion upgrade while I'm in there.
My buddy's harness is for an express van, the one's I found on eBay where from a search I did for Silverado. Is there anything I should look out for? Any years better than others? Or better from a specific vehicle? Will they all be equally tunable? I know I will have a wiring nightmare in front of me, so any advise to not go through it and find out I should've gotten or done anything different would be greatly appreciated.

 

[Texas82GP]

If you are going to pare down the harness yourself then I would just suggest getting the harness and ECM from the same donor vehicle. Go with a truck setup since it will be cheaper and easier to find. If you are ok with a drive by wire throttle body then stick with a Gen IV ECM and save the hassle and expense of using the 24X to 58X converter box. Even if you use a car intake, you'll be ok with a truck harness since you will have the harness so stripped down that you will end up customizing length and routing anyway.
On my brother's 78 Z28 we were working with an L96 (flex fuel successor to the LY6). We used the Lingenfelter converter box because we wanted a drive by cable throttle body which requires a Gen III ECM. Gen IV ECM's have no provision to drive an Idle Air Control Valve. We got a stand alone harness from PSI Conversions and it worked out great. I don't want to discourage you against doing your own harness though. My brother just decided to spend more money and less time on the harness. Here is a picture of his engine compartment. If you have other questions I may be able to answer them. I hope this helps.

 

[64nailhead]

I see no mention of your transmission, but if you're going to use a non-electronic trans such as TH350,TH400, 700R4, or 200-4R, then I think you'd be miles ahead going with something like this : http://www.efisource.com/shop/ls1-24x-modified-microsquirt-ecu-with-plug-and-play-harness/ IMO.

They also have kits that are plug and play for electronic transmissions for an additional $300 or so. I do realize that this is bigger outlay of money up front, but these systems work and the support is EXCELLENT. I'd recommend giving EFIsource a call to check it out. They'll tell you just what you need based on what you're using. Also, keep in mind, the software to program an MS is free. The software needed to datalog costs $50 for a LIFETIME subscription and the tune-ability of the MS is miles ahead, and easier, than HP Tuners. To make future mods like bigger injectors, adding forced induction, meth injection, etc, is beyond simple.

I'm not saying this will be best for your build, but at least it's another option to consider - good luck.

 

[Dinosport]

Thanks guys. That's some good info. At this time I'm running a 700r4.
I know they also offer a service where you can send your harness in to be reworked to your needs. But by the time you buy and send you could've just bought one. Unless I get it free which I may might or close to it.

 

[ldr]

Snoop around here. https://www.diyautotune.com/ If you are comfortable with a soldering iron you can build your own ecu and harness for a lot less than buying one. It takes a lot of reading and time. But the knowledge you gain will help you with your project.

 

[64nailhead]

Snoop around here. https://www.diyautotune.com/ If you are comfortable with a soldering iron you can build your own ecu and harness for a lot less than buying one. It takes a lot of reading and time. But the knowledge you gain will help you with your project.

DIYautotune is where I've bought all of my MS stuff, and they are a great bunch of guys as well - fabulous technical support! If you get a Megasquirt to run your LS then you'll never look back. The best way to describe the system is how the local dyno tuner described it me - 'a Megasuirt is like an OBD.5' because of the ease and speed of tuning. I once made 20 dyno runs in an hour. And that includes reveiwing the datalogs and dyno graphs and then making changes after every run.

I had the 1st Megasquirt that the local tuner had ever seen, to say he was impressed is understatement. This is coming from a guy that lives in HP Tuners.

 

[Dinosport]

Nice Ill keep the mega squirt in mind. The few things against it though are that I might end up with a factory harness and ecu for almost nothing. As far as building a unit I would love that but I dont know that I will have time to do that. My time is limited to say the least, Im going to scrounge the hrs I need to get the swap done as is.
Ill definitely keep it in mind if not now maybe at some time in the future if I modify it further.