1986 Bronco EFI Wiring - Ford Forums

xafalcon · 06-28-2004, 23:43

Does anybody have any info on wiring up an injected 302 from a 1986 bronco? It is standard speed density. The computer has a catch code of RK. The gearbox plug has been cut off. There is a 3 wire plug by the ecm that isn't connected, and another wire or two cut off in the loom. Otherwise it's all complete. I'd like to try and get it running.

Anyone able to help at all???

TIA
Tris

'92BigBronco · 06-29-2004, 11:49

I looked over my Ford computer info and I don't show an EEC catch code of RK for some reason. I'm assuming it's what was actually installed in the vehicle when you got it so I guess my listing is incomplete.

If you post a couple of pics of the unknown plugs and their surrounding area it should be easy to figure out where they go. I can also scan in the wiring diagrams for that year Bronco if it would help. Just let me know and I'll go ahead and upload them to this site. Shouldn't be too hard to trace the cut wires in the harness to their proper EEC pin locations and get it sorted out.

xafalcon · 06-29-2004, 23:44

Thanks very much for your reply and offer of help. Getting info on Bronco stuff in New Zealand is nearly impossible. I'll get some info and photo's back to you over the weekend. I've already removed all the tape from the harness, so tracing wires back to the eec should be easy. Wiring diagrams would be excellent. Any idea of the cylinder heads casting codes? How about the camshaft specs? Hydraulic roller or flat tappet?

Thanks again
Tris

xafalcon · 07-02-2004, 18:59

Hi

I've pulled all the insulation tape off the harness and traced wires back tothe ecu or other connection points. Here are the wires/plugs that I'm unsure about (some I've taken a guess at as the ??? indicates below). They are all on the main ecu harness. Some of the colours are a little faded and dirty. I think I've got them correct, but colours like white yellow tan can sort of become similar after 17 years of dirt and grime.

1) Orange wire, plug gone, runs from the same harness break-out point as the injector harness plug and goes to ecu pin 50.

2) Grey 3 pin plug right near ecu.
Black/green wire joins lots of other back/green wires further down the harness and goes to ecu pins 40, 60 and a relay next to ecu
Red wire joins lots of other red wires further down the harness and goes to ecu pins 37, 57 and the relay next to the ecu
Tan/green wire goes to ecu pin 24

3) Black/purple wire, plug gone, joins lots of white/blue wires (one of these white/blue wires then goes to the capacitor mounted on the TFI coil bracket, and another goes to the relay next to the ecu).

4) 8 pin round plug (colours are the main harness wires)
Red/white = coolant temperature ???
White/red = oil pressure???
Green/yellow wire joins lots of other green/yellow wires further down the harness (one of these green/yellow wires then goes to the TFI coil, another goes through a resistor to ecu pin 4).
Black/green wire joins the other black/green wires in the harness
White/blue wire joins the other white/blue wires in the harness
White/pink (or maybe white/purple) goes through a diode then to ecu pin 30
Red/blue wire goes to TFI distributor
Red wire goes to a relay

5) Green/purple wire (single pin grey plug) goes to ecu pin 10

6) Two yellow wires with fusible links are presumably 12V +ve input direct from the battery

7) Black wires with ring connectores are presumably earth connections.

Vacuum hose connections

1) Red goes from manifold to fuel pressure regulator??

2) Green goes from solenoid to egr???

3) Black goes from a different solenoid to ???

4) Pink = blocked off.

Finally, is the bosch cylindrical part with a porcelain tip a one wire O2 sensor? It is joined to a green wire coming out of the injector harness.

Any help that you can give me is very much appreciated.

Cheers
Tris

xafalcon · 07-04-2004, 02:01

OK, I think this is a 1987 bronco engine (the lower intake manifold is an E7 part). I think I've figured out most of the connections. All I need now are some 8 pin plug confirmations.

round plug (colours are all the main harness wires)
Red/white = coolant temperature ???
White/red = oil pressure???
Green/white) wire joins lots of other green/white wires further down the harness (one of these green/white wires then goes to the TFI coil, another goes through a resistor to ecu pin 4). Tacho???
Black/green wire joins the other black/green wires in the harness. Earth???
White/blue wire joins the other white/blue wires in the harness. Power on start & run???
White/pink (or maybe white/purple) goes through a diode then to ecu pin 30. Power on start with clutch in???
Red/blue wire goes to TFI distributor. Power on start???
Red wire goes to a relay. Fuel pump???

Does this sound right??

Thanks for any help you may be able to provide.

Cheers
Tris

'92BigBronco · 07-06-2004, 19:32

OK, Sorry for the delay. I've been short of time lately and haven't had time to type up a response. I'll print your posts out and try to figure it out when I have some time tonight. My apologies for leaving you hanging. I'll post back tomorrow sometime if all goes well.

xafalcon · 07-08-2004, 18:34

Hi

No problems with the delay. I've got plenty of other jobs to keep me busy. The only part I think I need help with now, is that darn 8 pin plug. There are a couple of wires I'm not really confident about. The colours on the wires are also a little hard to see, but the above are my best guesses.

Thanks again for any help you may be able to give me.

Cheers
Tris

'92BigBronco · 07-12-2004, 14:14

Wow, busy week here but I have a few minutes so I'll try and help the best I can. Here's the wiring diagram.

http://webpages.charter.net/brianreid/diagram1.jpg

The file was too large to upload to this site so I uploaded it to my personal webspace.

The wiring diagram for the '86 model year should be accurate since it is an '86 but if things don't look right, let me know and I'll scan the pertinent '87 diagrams in.

It's real tought to make heads or tails of the wiring by the colors as they do fade and the same colors are often used more than once in some applications. The only sure fire way to do it is to trace every wire back to its ECU pin and go from there. I'm assuming the unidentified wires do not have the plugs attached, so tracing them back to the ECU connection at the firewall is the best way to be sure you don't make any potentially costly mistakes.

I hope the diagram helps you a little.

Regarding your questions.....

Temp Sensor: light green/yellow and black/white for '86 and '87

Oil pressure sender: white/red

Tach: the wire you mention coming from ECU pin 4 should be dark green/yellow not white so I'm assuming it's well faded. That wire does in fact go to pin A10 in the instrument cluster. A10 is the connection at the tach.

I'm not sure on the black/green wires you mention as a possible ground. Where do they come from?

The wire running from ECU pin 30 is in fact the neutral safety switch, although I show different colors for those wires.

I'm assuming your TFI module is mounted on the distributor rather than on the inside of the engine compartment on the drivers side against the firewall on a heatsink?

I have no clue on the red wire. Is it a large diameter wire?

Hope that helps you get started and I do apologize for the delay but life's been hectic lately. Have fun!

Brian

xafalcon · 07-14-2004, 00:26

Hi Brian

Thanks for the wiring diagram, it has filled in many of the blanks. I still have a few questions. It would be great if you had the time to answer them if you are able to. The TFI module is mounted on the distributor as you suspected.

1) Are ignition switch pins 11 and 12 12V+ve on start and run?
2) How is the neutral safety switch wired in a manual? Pin 30 to 12V+ve, earth, or no connection?
3) On the TFI distributor there is a red/blue wire running to the 8 pin plug. This comes out of the other side of the plug as a Red/grey wire. Does this go to the start position of the ignition switch.
4) What is an infrared milage sensor? Do I need one or can I leave it out?

Thanks again for your help.

Best regards
Tris

'92BigBronco · 07-14-2004, 12:15

Tris, Here's my attempt at answering your questions.

1) ignition switch pin 11 should get battery voltage with the key in the run position. pin 12 should get battery voltage in the start position.

2) I show the neutral safety switch(AKA clutch switch) having 3 wires, 2 of which merge together at the switch, with the third coming from the ignition switch pin ST. The wire running from the EEC pin 30(white-pink) merges with the red-light blue wire from the TFI module at one pole of the switch. The wire from ignition switch pin ST comes in to the other pole of the neutral safety switch.

In other words, battery voltage runs from the ignition switch (pin ST) to the neutral safety switch. If the switch is open (clutch not depressed), the power will not flow through to complte the circuit. If the clutch is depressed, the switch is closed and battery voltage will flow through the neutral switch and engage the starter relay as well as power the TFI module and EEC pin 30.

3) Answer 2 should help clear up that TFI wire for you

4) I've never heard of anything called the infrared mileage sensor(it may be a regional thing) but it sounds to me like the vehicle speed sensor. If you leave it disconnected, your speedo will not work and it will store a trouble code. I show the wires for the speed sensor as being dark green-yellow and black-light green. Does that correspond to the wire colors at the sensor you're referring to?

Hope this helps you!

Also, just a little disclaimer. To the best of my knowledge, the information I'm giving you is 100% accurate based on the '86 model year Bronco with a 302 and manual transmission.....but I do not accept responsibility for any differences or printed errors. Use this info at your own risk!

That may sound like lawyer mumbo jumbo or something but I've had people take the info I've given them, apply it to a different application or model year, and then complain when it didn't work.

Good luck!

Brian