Internal Selonoid

geostang351

Member
Mar 30, 2005
946
0
17
Danb., CT
I have installed a new starter that has a solenoid attached to the starter. I ran the "S" terminal wire to the starter solenoid and ran positive battery post to starter. I ran a small jumper from positive to accessories as before. What do I run the "I" terminal wire to as it was on the old solenoid?
 
  • Sponsors (?)


An underhood pic would help us all.
I am writing this from memory, and I occasionally suffer from CRS disease, so someone feel free to correct me here.
It depends on which ignition system you have.
An original Ford points ignition system is designed to run on 6 volts. The "I" wire from the solenoid on the original system was designed to provide 12 volts to the points during cranking in order to make a hotter spark. (to start the car faster/more reliably). It goes from the solenoid to the distributor.
If you are running a duraspark electronic ignition, the "I" wire connects to the white wire of the ignition module, providing the same 12v boost during cranking.
In the mid '70s Ford redesigned the ignition switch to provide the voltage change, and deleted the "I" post on the solenoid. With Ford EFI, the computer controls the amount of voltage at the distributor, and thus, there is no "I" wire on the solenoid in that system either.
 
I have installed a new starter that has a solenoid attached to the starter. I ran the "S" terminal wire to the starter solenoid and ran positive battery post to starter. I ran a small jumper from positive to accessories as before. What do I run the "I" terminal wire to as it was on the old solenoid?

The new starter more resembles a 60s-70s GM type including the solonoid Ford placed on the inner fenderwell. To wire correctly one must understand the circuitry of ea design. Once you understand the function of ea wire you can assign it correctly to the other starter. I think checking how a similar year GM start circuit functions would be a good first step.
 
I had it started for about 5 seconds and can't get the starter to turn over again. During the 5 seconds it was running, there was a new vibration felt from the car. This was immediately after my T5 swap. I give up. Went to local garage to make arrangements to have them pick it up and bring to their shop for wiring fix and find out vibration. He thinks the new flywheel may be out of balance but I have no desire to get on my back and pull the tranny again. I'll keep updated.
 
I had it started for about 5 seconds and can't get the starter to turn over again. During the 5 seconds it was running, there was a new vibration felt from the car. This was immediately after my T5 swap. I give up. Went to local garage to make arrangements to have them pick it up and bring to their shop for wiring fix and find out vibration. He thinks the new flywheel may be out of balance but I have no desire to get on my back and pull the tranny again. I'll keep updated.

There are 2 different flywheel/flexplate balance weights for 302/5.0. Wrong flywheel may be causing the "new vibration".
 
  • Like
Reactions: 1 user
when you grabbed the t5 of the newer 5.0, did you take the flywheel and everything too?t here were two different imbalances used. All engines in the 90º-V family had a 28oz imbalance up to 1981. At that time it was changed to 50oz for the 302/5.0 but remained at 28oz for the 351W/5.8 while keeping the same bolt pattern. So mixing the imbalance is not a good idea if you value your engine.
 
You should have the following voltages coming from these terminals with the key in the "on" position. Zero volts at "S" and about 8 volts at "I". Th "S" terminal is nothing more than the positive side of a wire wound electro magnet. The negative side of the winding is internally attached to the mounting bracketof the solenoid and becomes a ground when the bracket makes contact with chassis ground by the bracket's contact with the inner fender when it's bolted down, completing the circuit.

When terminal "S" gets energized, (12 volts, key in "start" position), it creates a magnetic field that draws the contacts of the large terminals together and the "I" terminal also gets energized and delivers a full 12 volts at the same time. You will only have the 12 volts there when the solenoidis energized and voltage to the starter side, (large terminal), is present.

Again, the only time there should be voltage at the "S" terminal is when the key is in the "start" position. The "I" terminal wire will have 12 volts at the same time. This wire is connected to the coil circuit and provides a full 12 volts to the coil to make it easier to start the engine. It by-passes the coil's ballast resistorwire, which when in the "on" position, delivers a lower 8 volts to the coil (the voltage is now routed through the ballast? resistor) to prevent the coil from overheating and to help the ignition points to live longer.

If you were to disconnect the wire to the "S" terminal with key in the "on" position and take a voltage reading at the wire itself, it should show zero volts. At the "I" terminal, again disconnected and checked the same way, there should be approximately 8 volts present.

The 8 volts at "I" will have no effect on the solenoiditself in the "on" position because it is now an open circuit, at this point, unless thesolenoidis energized and the key is in the "start" position.

hope this helps!
 
  • Like
Reactions: 1 user
if that helps, i dont know. anything is better than nothing, it might let you know if something got fried in the process at the very least. just, use proper tools and volt meter when/if you do that. dont be like me and lick your fingers, flick the key over, ground out the other hand, and wait for the jolt... :nono:
 
  • Like
Reactions: 1 user
I once saw a Taurus 3.0 with a solenoid on the fender and one integral on the starter. as I recall, it was a 93-95 model. perhaps you or your mechanic could look the wiring diagram for that car up, and imitate it?
 
There are 2 different flywheel/flexplate balance weights for 302/5.0. Wrong flywheel may be causing the "new vibration".
I have a 90ish tranny and did not get the fly wheel with the tranny. Got a new one I think from KMJ with 157 tooth, 28OZ imbalance so should be good to go. They are picking the car up today and will know later.
 
You should have the following voltages coming from these terminals with the key in the "on" position. Zero volts at "S" and about 8 volts at "I". Th "S" terminal is nothing more than the positive side of a wire wound electro magnet. The negative side of the winding is internally attached to the mounting bracketof the solenoid and becomes a ground when the bracket makes contact with chassis ground by the bracket's contact with the inner fender when it's bolted down, completing the circuit.

When terminal "S" gets energized, (12 volts, key in "start" position), it creates a magnetic field that draws the contacts of the large terminals together and the "I" terminal also gets energized and delivers a full 12 volts at the same time. You will only have the 12 volts there when the solenoidis energized and voltage to the starter side, (large terminal), is present.

Again, the only time there should be voltage at the "S" terminal is when the key is in the "start" position. The "I" terminal wire will have 12 volts at the same time. This wire is connected to the coil circuit and provides a full 12 volts to the coil to make it easier to start the engine. It by-passes the coil's ballast resistorwire, which when in the "on" position, delivers a lower 8 volts to the coil (the voltage is now routed through the ballast? resistor) to prevent the coil from overheating and to help the ignition points to live longer.

If you were to disconnect the wire to the "S" terminal with key in the "on" position and take a voltage reading at the wire itself, it should show zero volts. At the "I" terminal, again disconnected and checked the same way, there should be approximately 8 volts present.

The 8 volts at "I" will have no effect on the solenoiditself in the "on" position because it is now an open circuit, at this point, unless thesolenoidis energized and the key is in the "start" position.

hope this helps!
Wow. That's a lot of info, Thanks! I did do some investigation on his but once I knew I was going to have a pro look at it, I lost thought of it and figured I shouldn't stress about it and let him take care of it. I'll know later today.
 
Received a call from the shop; Starter is not strong enough for my set up, Changing out starter to high torque starter. They also cleaned up some wiring at alternator.

They adjusted the carb for better response and tried to adjust distributor to adjust time a degree or 2 but it's frozen in place. :( Instead of breaking it free and BREAKING it, I'm just going to leave as is.

They got it started for about 15 minutes and there was no sign of vibration :D. Must have been just running rough for that first 5 seconds and I panicked about all new tranny stuff installed.

New starter to go in and pick it up today!!:spot:

Thanks for the help!