Aftermarket ECU (Motec) install in 308

There have been quite a few threads talking about aftermarket EFI and ECUs, but I don’t recall seeing anything really showing what goes in the installing one. That said, I though it made more sense to start a new thread for this install than to bury it in my supercharger thread as an aside. My engine is already equipped for EFI as part of the supercharger install, so that part of the install process will be missing, but I’ve seen several other threads that cover that pretty well anyway

My motec M800 came then other day, very exciting….now where to put it?

As a little back ground, this in my 3rd ECU for this car. My first one was a haltech E6k and I installed it and a MSD DIS-4 (4 coil distributor less ignition) in the trunk under the side panel where I removed the stock ignition controllers from and it worked good.

When I decided to put on an bigger supercharger, I needed bigger fuel injectors and the E6k couldn’t drive them and the distributor-less ignition, so I up graded to an E11v1. I installed it in the trunk, right where the E6k had been…but this time it didn’t work out too well. I had all kinds of odd intermittent problems that I just couldn’t figure out. It turns out the E11 has a bigger better chip that is apparently either gets hotter or is more sensitive to heat and it was over heating in the trunk. In hind-site the trunk was probably a bad idea right from the beginning.

So, since I had to re-instsall the ECU anyway and there where a few things I think I want that the haltech won’t do, I decide it was time to switch to a motec M800. The motec and the haltech have the same processor, so the trunk is right out…and motec manual is very clear about finding a cool spot to mount it, but where?

I’ve seen ECUs installed behind the seats on the fire wall and that is where I have my amps mounted….but the M800 cost $2500 ordered from Australia, they are $5000 from a US dealer, I’m not so sure I want it mounted any place it would be visible.

I pulled the dash apart looking for a spot and I think I found one, but it would mean changing out the fuse panel. As much as I’ll miss the crappy stock fuses that cause me problems a few times a year, I guess I’m going to have to part with them. They will be replaced with plug-in fuses found in most new cars. I found a 4 fuse hold that that would work and space to mount 5 of them giving me 20 circuits, 2 more than stock. The only problem is the terminals aren’t plated so corrosion could be a problem down the road…I’m going to look a little more to see if I can find a higher quality part, but this will work if I can’t.

Here’s some pictures
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Now that a spot is pick, it needs to be wired. I bought a motec flying lead harness, but I’m not real impressed with it, so that’s up on ebay rather than pay to ship it back to Australia.

I ordered a replacement haltech harness with mil-spec wire yesterday. Knowing it’s a pretty good quality piece and thinking the plugs look the same as the motec and easy enough to change if they aren’t. Of course now that I’ve pick the mounting location and measured, the wire will not even be close to long enough…it will have to go back.

The long wires mean ordering something custom or making the harness myself. Ordering custom is simply not in the budget, so I’ll be making the harness. The biggest problem about making the harness and also my main complaint with the motec harness is wire identification. Wire come standard in about 5 colors, if you hunt there are maybe 10 colors to be had….but there are 60 pins on the ECU. In the motec harness, they just grouped the wires, 8 fuel injectors, 8 white wires with on other identification. Haltech on the other hand has the wire custom made with colored stripes and different colors for every pin. Must nicer, but since custom is out of the budget, I need another solution.

I found a label maker that prints on heat-shrink tubing. The will let me buy standard wire and still ID everything…in fact it’s a bit nicer than color stripes since I can label it injector 1 or whatever and know where it goes without needing to look at the wiring diagram.

The next step is to order a LOT of wire and all the connectors. Wire is not wire BTW, it comes in many different grades. About the best wire for this type of application is MIL-W-16878/4 or 22759/16 spec. It’s fine stand which makes it very flexible, the conductors are plated so it doesn’t corrode, and the insulation is Tefzel which is good to almost 400F, 600 volts and is 1/3 the thickness of standard PVC insulation so the wire take up much less space. It costs more, but I think it’s worth the money.

Here's the cheapest place I found to order good wire
http://www.steinair.com/wire.htm

I’ll post more when I get it.
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PM me for the source of where I got mine...

The draw back with the great price is that the US dealers will not talk to you, you need to call the dealer you bought it from for tech help.

It took about a week to get it....after I got the credit card company to believe I was me and I wanted the stuff...something about expensive auto parts is forign countries sets off every alarm they have.

I have the motec wire harness on ebay if you want it
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&ih=017&sspagename=STRK%3AMESE%3AIT&viewitem=&item=270055769067&rd=1,1

 

Get it running you'll love it! I converted my haltech maps to motce speak and keyed them in, you can have that file now if you want it, or you can wait and I'll send you the tuned version....but you've got different injectors and fuel pressure, so your still going to have some work to do.

 

Thanks Bret. I want to stick with the aircraft grade wire and mcmaster gets $.60/ft vs. under $.20 at thte aircraft supply place....and I already odered about 1500 feet of it.

Is you car up and running...I know you've been working onit as long as I have been on mine?

 

Thanks Jeff.

I'd love to have motec build the harness, but it's just not in the budget

And since I biought my ECU in Australia, I don't think Jay will be very helpful either

 

Been there
www.mcmaster.com
Part number 4512T4

 

I didn't think there would be room, I'll take a look.

 

That's fair

Are you sure, I'm looking at the bits of the spec I can find on-line and it looks like the difference is irradiated vs non on the insulation...that's all I see. Doesn't matter, plated conductors and tefzel insulation.

Yes they do

 

The have a lot of wire colors too at not a horrible price. I may need to order more.