LTD LX CFI to EFI wiring ?s

[drivesa5]

Must get back to work on this project, so I have a few questions (and will have some more questions later I'm sure). It especially would be helpful to ask some of this to some of you who've actually done it, as when I started when I hit any snags, I didn't know anyone who had done it to ask. It was quite a while ago I started so now I've kinda lost track of where I'm even at. Oh and it's an 85. Anyway:

First, what does the black and white wire coming off the alternator attach to? Forgotten in time... :?

And... I'm assuming the stock fuel pumps from the LTD will not have anywhere near enough power to supply the 8 injectors, so do I need to drop the tank and put an in-tank mustang pump in?

Next, the wiring - I'm kinda going by the Ford Motorsport manual on how to do it, which isn't always very specific... basically it comes down to splicing in the wires from the EFI harness' green and brown connectors into the appropriate places (power sources, computer, gauges) on the LTD. I attached a picture of what I'm going by. Can anyone tell me if this looks right and what these might be attached to in your swap?

The only real progress I've made is getting the fuel pump wiring done (it primes). Then I had to move so I got distracted from the project again. Now I can devote some time to it and really want to get it running! A bunch of the wiring I've already done, but I think it's off, I have to get back into it and see what I can find out, but I'll start with the above questions... then once I see where everything is I'll ask some more if I have to.

I know it's long, but thanks for reading and for any help!

http://i25.photobucket.com/albums/c65/drivesa5/connectors.jpg

[Marz]

I believe the black/White wire is for the choke.

LTDScott had the stock fuel pumps on his LTD LX for a while before he converted over to true duals. Remember... CFI and SEFI need 39psi... The stock CFI Pumps would work just fine on 8 injectors. The LTD LX use two 52# injectors. The SEFI use 8 19#.

But LTDScott did post information here on this section about his single fuel pump conversion.

[LTDScott]

Black/white wire? I don't believe my car had that one:

http://ltdlx.org/alternator_files/image026.jpg

I probably can't answer the other questions about the wiring. I did not do the conversion on my car, and it was done with stock Mustang wiring, not the FMS kit.

The stock two pump system powered my car just fine, but I did eventually convert to dual and use a high pressure in tank pump.

[drivesa5]

Hey thanks for the replies, I'll take a picture of the alternator wire, I'm pretty sure it's black and white? So you think that wire coming off of the alt. was for the choke and is no longer needed then?

Good to know about the fuel pumps, thanks marz - I'm stickin with the stockers for now then. Just wasn't sure because 8 19s = more than 2 52s.

Thanks for the pic scott, I'll take a look and see if mine's the same. Also, I'm using stock Mustang stuff too, not a conversion kit - just am using the manual because it's the same basic procedure with splicing in what needs to be.

[LTDScott]

It's been so long that I can hardly remember what the stock CFI setup looks like, but I believe Marz is right. There was a wire from the alt to the round heater element thingy (not really a choke) on the passenger side of the CFI unit.

[paul78zephyr]

Be very very carefull when using the FMS EFI manual (booklet) to make any connections or modifications to a stock factory Mustang EFI harness. The stock Mustang harnesses vary significantly in their wiring from year to year even though they look similar. And the FMS harness is wired even diffently from all the Mustang harnesses. Yes, it can be a nightmare without the proper documentation. What is most confusiong is all the EFI harnesses use the same basic physical connector housings (the plastic parts) but have different wires in them depending on year. Essentially the FMS manual is applicable to the FMS harness ONLY in terms of exact wiring.

I have in my possesion a 1989 harness and a 1990 harness and have documented the differences (and similarities) so I know they exist. And I have the FMS EFI manual and know that the wiring they show does NOT match either of the EFI harnesses I have. Some of these issues have been discussed here and at other 5.0L EFI conversion forums.

Paul

[drivesa5]

Ugh. Thanks for that, Paul! Yeah, that's kinda the problem I'm having - I don't really know what's what anymore. So, do you think you could direct me to either some of these posts you're talking about, or tell me about the differences? From my original post and the picture I attached, do you see any problems? I'm not really sure what to go by... Thanks again!

[paul78zephyr]

There are lots of posts/threads here at FEP concerning EFI conversions. You can find them using the search function. Use the key words 'EFI harness' or EFI conversion'. The reason that I will not direct you to them myself is that in many cases I do not agree with the info posted - there is some incorrect info out there. So do a search and you will get some feel for whats involved.

I can try to help you - but its difficult as I cant see where your at with your project. You are converting a 1985 LTD LX from CFI to EFI, correct? What engine are you converting to SD or MA? Are you using a factory Mustang or FMS EFI harness? If Mustang, what year - this is CRITICAL to know. If you do not know I can help you identify it.

Paul



Paul

[drivesa5]

Thanks Paul, I was wondering why you wouldn't just link, but now I see. I'll take a look and see what I find, but I'll talk to you as well.

First of all, 85 LTD LX CFI to EFI, correct. I'm converting to MA. However, when you say engine, I assume you just mean what system, since I'm not actually swapping engines - just swapped the upper & lower intake, throttle body, mass air, etc. onto the stock shortblock & heads. I'm using a factory Mustang harness, that I "think" is a 91, but if you can help me identify, that would be good because I'm not 100% sure on that.

[paul78zephyr]

Scott, I will PM you to take this 'offline'.

Paul