77 bronco to 1990 tc efi wiring question

[spap]

Hey, I have looked all over this site and other areas but can't seem to find an answer. I am doing an efi swap using the original 1990 Lincoln tc harness and keeping the power distribution box in the engine compartment.

I need to know about the 3 alternator wires (that go to the 3 prong alternator harness) that come out of the pasenger side of the bronco. The 10g black/yellow' 10g black/red and the small green red. Should I just connect both big wires to the 12v positive side. I know they both go in under the dash , and I am not sure what to to with the small green / red wire I beilve that is for the ampmeter. I have all of the 1990 alternator harness in place to the power distribution box so these wires will not go to the alternator.and the starter relay is on the starter motor. Any help is apreciated

 

[DirtDonk]

Which alternator is on that '90 engine? Is it a 2G or 3G do you know? One way to tell is if it has 1 harness plug and 1 large lug with red plastic insulator it's a 3G. If it's got a spot for 2 harness plugs, then it's a 2G.

If it's a 3G you'll need to wire it differently and leave the ammeter out of the circuit. If it's a 2G and you decide to use it (even though many here will try to talk you out of it) and you verify that it's still just a 65 to 70 amp output, you can continue to use the factory ammeter and wiring.

So you are hooking all this to a stock original Bronco wiring harness, yes?

You might get away with wiring the starter solenoid direct to the battery, but if you experience any instances of the starter continuing to run even after you let off the key, you should reinstall your original starter relay on the fender to use as an "isolator" to keep any other feedback through the system from energizing the starter.

Got any pics of the general and detailed layout of the power distribution center and it's connections?

Paul

 

[spap]

Hey Paul. Its a 65 amp 2 g with all of the stock 1990 wiring harness and that all plugs into the stock power distribution box sorry I don't have a pic but I will try the power just wonder if the black/yellow 10g wire and the black/red wire both need a 12v + '. I believe they are both hot(positive) as they go back under the dash. Thanks for you help

 

[DirtDonk]

One or the other, at least, will need power to feed the chassis wiring.
The Black w/red is the traditional battery side, and the Black w/yellow is the traditional alternator output side.

The 2G was a problematic unit originally. There have been some upgrades to the connector and wiring since then though, so if you want to keep it, you can. But just be aware that EVERY CONNECTION AND CIRCUIT must be in tip-top shape and resistance should be kept to an absolute minimum, to avoid a potential meltdown or fire.
Nope. Not kidding.

Using the 2G, since it's output wire(s) are already attached to the distribution block, you can attach both of the Black wires there too, but you'll lose your ammeter.
If you want to keep the ammeter, you would have to disconnect the alternator from the PDC and attach both Black output wires from the alternator to the Black w/yellow Bronco wire only. Then connect the Black w/red to the main buss of the PDC. Then, a wire from that same stud to the positive side of the battery.
It's a little awkward, but should work with the 65 amp output.
Just make sure that all the connections are good, clean and tight. And check the bullet connector there at the back of the ammeter. It's where the wires come together and can get rusty. If it's clean and tight, you're in good shape.

The problem I see is with using the original output connector from the alternator. Unless you know it's already been upgraded, you should get a new updated one from the local auto parts store.
It has a tighter contact, tighter weather seal, and better wire retention. Keeps meltdowns and future fires to a minimum. ;D

Paul

 

[spap]

Thank you sir that's what in needed to know, I checked the alternator connections and they look new . this town car only had 34 k miles on and the whole car was only 700 bucks I will eventually switch over to a 3 g but I want to get this running first. But I will carry more fire protection first
Have a great weekend
stuart