Duraspark Starter Solenoid

[jaredm_k]

Hello - I have a durasparked 1985 bronco ii that has fried a couple of solenoids. It has a 3 wire solenoid on it - so I replaced it with one. However - when I look up parts for a 1978 Pinto (which is basically the ignition that I am running) it only has 4 wire solenoids as an option. Does anyone know which one I should have? Or if it matters? If I should be running a 4 wire, do I need to connect a wire to that if there isn't one there now? Any advice is appreciated!

Jared

 

[RonD]

No you don't need the 4 post solenoid(RELAY).
the 4th post, "I", was for the coil, it gave the coil full voltage when starter motor was engaged, in these older vehicles coils got power thru a resistor, so only had 7-8volts when engine was running, that was plenty of spark voltage when engine was started, and it kept coil cooler so it lasted longer, but voltage was too low for starting a cold engine.
So when you activate a 4 post solenoid(RELAY), the "I" post got full voltage same as starter motor post, and "I" post was connected to Coil "+"

You can use a 4 post starter relay(solenoid) in place of a 3 post, nothing hooks up to the "I" post

 

[jaredm_k]

Got it. Thanks RonD! I have a couple spares of the 4 post solenoids so I will throw one of those on there and see if I can get it running again. Thanks!

 

[enginepaul]

If you fried a couple of solenoids you may have some sort of wiring problem. A genuine Ford unit can last well over 20 years. Aftermarket ones aren't as good, but they should last a very long time.
Double check the condition of your wires.

 

[RonD]

these starter relays are very easy to wire.

On one large post you connect battery "+" and ALL the other wires, thats the power distribution point for the vehicle.

second large post has 1 wire/cable that goes to the starter motor, nothing else

And there is no "order" in these 2 large posts, no forward or backwards, pick one as power distribution and the other is starter motor.

Small "S" post is for the, usually red/blue, wire that comes from the Key switch, it will have 12volts when key is turned to START, this wire activates the starter relay(solenoid)
This 12volts also passes thru a clutch or Neutral switch before it gets to the relay, to prevent starting in gear.

 

[85ranger2.8]

Similar issue

I am doing the duraspark as well and when I put the new battery in and connected the ground cable to the battery, the solenoid started smoking and 1 wire from the starter solenoid to the frame immediately started smoking and melted. This took about 1-2 seconds and I disconnected the ground. After reading the hookup advise I'm wondering if my connection is wrong was already like this).

The solenoid was hooked up as follows; + from battery connects directly to one side of the solenoid only with large post (no connections anywhere else). The ground from battery goes to the frame. On the opposite side large post of solenoid, there is a red wire going to the starter. On the post where the + battery is connected to the solenoid, there are 2 small wires attached as well. One is orange with a fuseable link and I haven't traced it yet but, I believe it would go to the ignition? The other wire is black and joined with some other wires from the old computer, then attached to the frame ground where the negative side of the battery connected. This seems wrong to me but I am no mechanic. If the + battery is on the same solenoid post as a wire going to the frame ground which is connected to the - battery it seems to me it would be a problem. The truck ran previously (like crap though), and I have never messed with the solenoid before so I am confused. Maybe my 16 year old and his buddies made a mistake? I will follow with some pics, if anyone can help, I would really appreciate it. Thanks

 

[85ranger2.8]

Pics of the solenoid wiring

The small black wire joins to the frame ground that the - battery post connects

 

[85ranger2.8]

Plug the black wire connects to. The ones cut went to the removed computer

 

[85ranger2.8]

How the plug connects to frame ground

 

[RonD]

There is no Ground wire to the Starter Relay(solenoid).

It is 12volt wires only.

Starter relay's case is grounded to inner fender by it bolts, so no Ground wire is needed.


Some of the wires that will be on the starter relay's Battery "+" post are:
Alternator B+ wire
Wire to Fuse box

 

[85ranger2.8]

Thanks, I appreciate the information!

 

[jaredm_k]

I did some more hunting this weekend and found that my wire from the solenoid to the starter has burned through the split flexible wire protector as well as into the cable itself. I could see wire! So I am sure that is a contributing factor to my roasting of solenoids. I'm going to go ahead and replace all those cables (battery to solenoid, solenoid to started, and battery ground wire). Thanks for all of the info!

 

[kimcrwbr1]

Another good upgrade is add a 8g wire from battery negative to ground on the alternator body especially in colder climates in the winter.

 

[jaredm_k]

Thanks kimcrwbr1. I'll go ahead and do that while I'm in there. Quick question about fusible links....mine was connected on the battery site of the solenoid and then taped off on the other end. Is that ok? Or does it need to be connected to the circuit on both sides? I would think it has to be connected otherwise how would it interrupt the current if it blows....thanks for your time.

 

[kimcrwbr1]

The fusable link is on the battery side and provides power to everything. It is basically a smaller guage wire designed to burn up in case of a short so you dont light up the wiring harness. If the link blows you need to find the short before replace it with the recommended link.