Wanting to find good info for builds with Factory Ford EFI wiring

[wirelessace]

Hello all, this is my first post, I love all the info on this site. I see that most of the builds are done with the chassis wiring kit from FF. I did not go with that for budget concerns and am trying to stick to the donor car parts and processes. What I would love is a build with good pictures of a donor build with a 1989 style mustang 5.0 donor car.

[MPTech]

I built an MK4 basic kit 10 years ago, however I did not use a donor. I watched this site (fuel tank, radiator, etc) and bought most of the parts new / rebuilt from O'Reilys. I pieced together all new parts for the rear-end / spindles (IRS), had a trans rebuilt, and bought a rebuilt and mildly upgraded 5.0L. I bought a Painless wiring harness from a member too. Realize that an '89 donor means parts that are 35 years old. I would not put a 35 year old wiring harness, fuel tank / pump, radiator, brakes / master cylinder, bearings, rear axle, trans, even motor, etc in a new Roadster. Asking for trouble.

Sorry for the reality check. I understand budget, but you will create so many headaches, you will hate it.

[Jeff Kleiner]

I’ve built 2 with Ford EEC-IV EFI 5.0s and dieted Fox Mustang harnesses. Not really a lot of pictures…what do you want to know?

Jeff

[JohnnyB]

Hello all, this is my first post, I love all the info on this site. I see that most of the builds are done with the chassis wiring kit from FF. I did not go with that for budget concerns and am trying to stick to the donor car parts and processes. What I would love is a build with good pictures of a donor build with a 1989 style mustang 5.0 donor car.

For what it's worth my build site is still up at: https://cobra.spintime.org/
It looks a little funky with modern browsers since it was done last century but you might find something useful.
I used an 89 Mustang donor complete with donor gauges and a dieted wiring harness.

[Flip Smiley]

20 some years ago I built a MKII and used a 1990 LX donor. I dieted the harness myself. At that time Mark at Breeze offered a kit to aid in the process. The kit included hardware and detailed instructions with full size wire diagram drawings. Give Mark at Breeze a call, he may still be able to provide the information and expertise you are looking for.

[Papa]

Hello all, this is my first post, I love all the info on this site. I see that most of the builds are done with the chassis wiring kit from FF. I did not go with that for budget concerns and am trying to stick to the donor car parts and processes. What I would love is a build with good pictures of a donor build with a 1989 style mustang 5.0 donor car.

I know you mentioned budget as a key driver, but wanted to let you know that Holley offers plug & play computer and harnesses for several of the older Ford engines. That could really simplify your wiring if you wanted to go that route.

[Flip Smiley]

If you need further info on donor building you should refer to the build manual . I haven’t seen the latest revision but know the early manuals had good directions and included pictures to assist in the build. If you don’t have a manual get one. If you are wanting to complete a donor build maybe look for an older manual that includes that information. With the manual and the information available here you should be good to go. There are a lot of people on here that have accomplished this and a here to help.

[wirelessace]

I totally understand your thoughts on that. I know the history of the donor as it have been a family car for 20 of the years it was on the road. Super well maintained but the body was beyond reasonable repair not a straight panel on it.

[wirelessace]

I know you mentioned budget as a key driver, but wanted to let you know that Holley offers plug & play computer and harnesses for several of the older Ford engines. That could really simplify your wiring if you wanted to go that route.

Does the Holly harness still require the ford chassis harness and it just connects from ecu to motor?

[Papa]

Does the Holly harness still require the ford chassis harness and it just connects from ecu to motor?

My understanding it the Holley setups replace all the EFI connections to the engine and computer. Most use the Terminator ECU with a harness that ties into all the Ford sensors and ignition. It won't replace any of the chassis harnesses.

Example: https://www.holley.com/products/fuel_systems/fuel_injection/terminator_x/terminator_x_and_x_max_ford_kits/terminator_x_ford_kits/

[Jeff Kleiner]

As I said in the earlier reply I have built 2 "donor type" builds. Neither one used parts from donors without first being completely rebuilt or replaced/upgraded outright. Here's a collection of photos from my own car (if you click on a photo it should open any related text). Hard to believe that one was almost 17 years ago!!

https://link.shutterfly.com/IkXt9LKm0Db

The second one was documented in a couple of threads on "the other" forum. Since the photos were through Photobucket they may or may not show up.

https://www.ffcars.com/threads/another-build-thread-5717.296075/#post-2706826

https://www.ffcars.com/threads/time-to-graduate-5717.505569/#post-4752481

HTH,
Jeff

[CraigS]

I would re-think using anything from an 89 donor car for three reasons. 1- The wiring itself is so old that the insulation is more likely to crack than bend. The plastic connectors are likely to have the small locking tabs crack off also. 2- The ecu will likely die. At one time there were a few capacitors inside that would die and could be replaced by someone skilled in soldering circuit boards. At 34 years old I suspect there are way more problems now. Search around for a replacement ecu and or ecu repair shops before committing to using this old donor. 3- Back in the day FFR used the instrument cluster from the Mustang. It was a colossal pain to disassemble it to get the gauges out and place them so they looked correct in the FFR dash. Then we took the circuit board that the gauges were originally attached to and mounted it somewhere behind the dash. So the cluster assembly was basically disassembled and the parts mounted somewhere. Honestly it was a real mess.

[weendoggy]

I would re-think using anything from an 89 donor car for three reasons. 1- The wiring itself is so old that the insulation is more likely to crack than bend. The plastic connectors are likely to have the small locking tabs crack off also. 2- The ecu will likely die. At one time there were a few capacitors inside that would die and could be replaced by someone skilled in soldering circuit boards. At 34 years old I suspect there are way more problems now. Search around for a replacement ecu and or ecu repair shops before committing to using this old donor. 3- Back in the day FFR used the instrument cluster from the Mustang. It was a colossal pain to disassemble it to get the gauges out and place them so they looked correct in the FFR dash. Then we took the circuit board that the gauges were originally attached to and mounted it somewhere behind the dash. So the cluster assembly was basically disassembled and the parts mounted somewhere. Honestly it was a real mess.

Amen to that! I just worked on a sloppy stock build and did a LOT of changes. Using that old stuff is just not worth the $$ you think you'll save. As Craig said, try to find or even attempt to get a good ECU if that one goes bad. You'll be spending more $$ to change it then anyway. I understand budget, but I think you're asking for trouble. However, when I did my build over 25yrs ago, I dieted the hell out of the stock harness and move a lot of wires to other connectors to eliminate the mass of plugs. Takes time, but did work. Bright side is I put a new Painless in when I did my frame off 6yrs ago and wouldn't hesitate to advise the same. jmo

[wirelessace]

I appreciate everyone's concerns. and i knew as soon as i posted my plan i was gonna get opinions that my build path is "questionable", a few details, i have rebuilt the trans and engine, designed the engine rebuild for boost as i plan to twin turbo, I have been looking into aftermarket fuel management as the stock ecu will not get the job done. Larger injectors and a 400 LPH fuel pump. As for the gauge situation, i ordered the Autometer gauge package from FFR and will also be ordering the auto meter boost and air/fuel gauges. Based on my research the Holley terminator x and harness is in the lead for that. but if there are other options to consider, let me know.

[Jeff Kleiner]

Well in that case much of what was said in the earlier replies is moot. I guess we must have been misled with the title of the thread—-“…info on builds with factory Ford EFI wiring” which you’ve now said that you won’t be using.

Jeff

[wirelessace]

Well in that case much of what was said in the earlier replies is moot. I guess we must have been misled with the title of the thread—-“…info on builds with factory Ford EFI wiring” which you’ve now said that you won’t be using.

Jeff

Yep i see what i did there. I am so new to using these message boards.