Ignition switch continued(sorry I couldn't find my other post to latch onto)

[ChiefDan]

I was busy rewiring the ignition switch today. I got the old female terminals out of the plug, but I couldn't reuse them. I went with some regular crimp type spade plugs and inserted them into the plastic plug. It works, however since they don't latch when you plug the wire plug back into the switch body, the new spade plugs get pushed back up. I remedied this by taking a small screwdriver and pressing the female spade back into the plug. Seemed to work.<br>What I found is a bad ground at the starter solenoid. Not sure what is going on, but if the original ground is connected, can't start. I took it off and ran a ground straight from the battery, and it started. My question is, can I go ahead and give myself a new ground from the battery to the solenoid, or is there a reason the ground comes from somewhere in the truck? I think I am safe, the Hayes schematics just showed a ground, but I look to the wisdom here for verification.<br><br>Thanks<br><br>Dan

 

[eBronc]

The starter solenoid shouldn't be "grounded" to anything except wherever it's bolted to- the only circuits that connect to are the 12v start signal from the ignition switch, the 12v "bypass" wire that feeds a full 12v to the coil during cranking, and the battery on one big terminal and the starter on the other. <br><br>The starter solenoid is just a big switch that handles all the battery current (500-600 amps) when the starter is engaged. The rest of the time it just sits there. <br><br>The battery should be grounded to either the frame or the engine block, and the engine block to the frame. The "+" post of the battery goes straight to the starter solenoid.

 

[ChiefDan]

The control voltage for the solenoid connects to the 2 posts on the front of the solenoid. There is +12V and ground. According to the schematic there is nothing special about the control ground, but mine has a wire which is run from the inside of the truck, so that is why I was wondering if there was something I was missing.<br><br>[quote author=eBronc link=board=5;threadid=9913;start=0#71540 date=1033956635]<br>The starter solenoid shouldn't be "grounded" to anything except wherever it's bolted to- the only circuits that connect to are the 12v start signal from the ignition switch, the 12v "bypass" wire that feeds a full 12v to the coil during cranking, and the battery on one big terminal and the starter on the other. <br><br>The starter solenoid is just a big switch that handles all the battery current (500-600 amps) when the starter is engaged. The rest of the time it just sits there. <br><br>The battery should be grounded to either the frame or the engine block, and the engine block to the frame. The "+" post of the battery goes straight to the starter solenoid. <br>[/quote]

 

[eBronc]

Hmm.. the 2 small posts on the solenoid should be labled "S" and "I". The "S" terminal is for the Red/blue wire from the start position on the key switch, and the "I" terminal is for the brown wire that leads to the positive side of the coil to provide a full 12v while the starter is engaged (it's basically a bypass around the factory red resistor ignition wire from the key switch). <br><br>Neither of these should be a "ground" wire- if you've got a short to ground somewhere in the harness, I can see why a meter would show it at ground potential, but it shouldn't be. That extra wire you've got coming from the inside of the truck sound like a previous owner's "fix" around the real problem. <br><br>The Red/blue wire should only have 12v on it when the key switch is turned to the "start" position- otherwise the solenoid will be energized all the time. The brown"bypass" wire will have power on it both in "start" and "run" positions- 12v going OUT to the coil during cranking, and slightly less on it whenever the ignition is on, because it's common with the red "resistor" igntion wire at the coil + terminal. The red "resistor" wire knocks down the power to the coil to 9-10v to help the points in the distributor last a little longer. If your rig has been converted to electronic ignition, get rid of that resistor wire to the coil and run a new 12 ga wire from the key switch to the coil (maybe that "new" wire on your truck is what this is). There is no "control ground" to the solenoid. <br><br>Most newer cars with computers DO use "control grounds"- all the accessories, solenoids, sensors, etc have power to them at all times, and the computer controls them by grounding the outputs to them- that way, if there's a short to frame ground somwhere in the wiring, it won't blow the computer. Older cars and trucks like our EB's have everything grounded, and supply power to it to activate it.

 

[ChiefDan]

Are you sure the 2 small posts on the front of the solenoid are not +12 and Ground?<br>The solenoid is just a relay, and I think the 2 posts are the control to basically turn on the switch to supply power to the started when the key is turned to the start pos, and when the key is in the Run pos, the switch is open again. If you look here:http://www.broncograveyard.com/dia/6/wirschem1_16.jpg<br>the solenoid is at the left in the middle, it shows +12 going to one side of the coil in the solenoid and Ground on the other end.<br><br>The truck starts and runs fine when I jumper the ground in. The extra wire I mentioned is stock, so that's why I am a bit confused.<br><br>[quote author=eBronc link=board=5;threadid=9913;start=0#71647 date=1034014838]<br>Hmm.. the 2 small posts on the solenoid should be labled "S" and "I". The "S" terminal is for the Red/blue wire from the start position on the key switch, and the "I" terminal is for the brown wire that leads to the positive side of the coil to provide a full 12v while the starter is engaged (it's basically a bypass around the factory red resistor ignition wire from the key switch). <br><br>Neither of these should be a "ground" wire- if you've got a short to ground somewhere in the harness, I can see why a meter would show it at ground potential, but it shouldn't be. That extra wire you've got coming from the inside of the truck sound like a previous owner's "fix" around the real problem. <br><br>The Red/blue wire should only have 12v on it when the key switch is turned to the "start" position- otherwise the solenoid will be energized all the time. The brown"bypass" wire will have power on it both in "start" and "run" positions- 12v going OUT to the coil during cranking, and slightly less on it whenever the ignition is on, because it's common with the red "resistor" igntion wire at the coil + terminal. The red "resistor" wire knocks down the power to the coil to 9-10v to help the points in the distributor last a little longer. If your rig has been converted to electronic ignition, get rid of that resistor wire to the coil and run a new 12 ga wire from the key switch to the coil (maybe that "new" wire on your truck is what this is). There is no "control ground" to the solenoid. <br><br>Most newer cars with computers DO use "control grounds"- all the accessories, solenoids, sensors, etc have power to them at all times, and the computer controls them by grounding the outputs to them- that way, if there's a short to frame ground somwhere in the wiring, it won't blow the computer. Older cars and trucks like our EB's have everything grounded, and supply power to it to activate it. <br>[/quote]

 

[Broncobowsher]

The ground for the solenoid is the metal bracket that bolts it to the body. <br><br>There is the possibility that you have a heavy duty relay (not a ford starter solenoid) from an industrial supply house. Some of those look like the standard Ford solenoid, but are different. If the body is steel and round this might be what you have.<br><br>If it is plastic and real chunky looking, it is the ford Solenoid.

 

[ChiefDan]

Well I do have a heavy duty one now since I kept burning the other ones up.<br>Looking at the schematic, I see what eBronc is talking about, but it looks like the wire to the points runs from the big stud that the +12V from the battery connects to. But my suspect wire is brown. Hmm... If it wasn't for all that damn electrical tape I could see what goes where. <br><br>[quote author=Broncobowsher link=board=5;threadid=9913;start=0#71652 date=1034016790]<br>The ground for the solenoid is the metal bracket that bolts it to the body. <br><br>There is the possibility that you have a heavy duty relay (not a ford starter solenoid) from an industrial supply house. Some of those look like the standard Ford solenoid, but are different. If the body is steel and round this might be what you have.<br><br>If it is plastic and real chunky looking, it is the ford Solenoid.<br>[/quote]

 

[Rustytruck]

The origional battery ground cable on my Bronco ran from the negative pole to the block on the passengers side of the engine about a third of the way down there was a metal flag attached to a stripped part on the cable and was screwed to the sheet metal of the inner fender apron just below the starter solonoid to help to provide chassis ground and also limit cable movement. When I replaced the cable of course there was no flag on the new one so I provided an additional ground from the bolt of the cable clamp to the body with a number 8 wire and a couple of eyelets. The soloinoid grounds through the bolts holding it to the chassis. The extra wire on the solonoid sends full battery voltage to the coil to bypass the resistor at the coil during starting to aid in cold starts.

 

[ChiefDan]

So I could remove that wire from the solenoid and the truck should still start correct?<br>Sorry to keep beating on this, but I just want to make sure I have a grasp of what is going on.<br>[quote author=rusty truck link=board=5;threadid=9913;start=0#71661 date=1034017514]<br>The origional battery ground cable on my Bronco ran from the negative pole to the block on the passengers side of the engine about a third of the way down there was a metal flag attached to a stripped part on the cable and was screwed to the sheet metal of the inner fender apron just below the starter solonoid to help to provide chassis ground and also limit cable movement. When I replaced the cable of course there was no flag on the new one so I provided an additional ground from the bolt of the cable clamp to the body with a number 8 wire and a couple of eyelets. The soloinoid grounds through the bolts holding it to the chassis. The extra wire on the solonoid sends full battery voltage to the coil to bypass the resistor at the coil during starting to aid in cold starts.<br>[/quote]

 

[eBronc]

The (factory) small brown wire that's attached to the solenoid is the power bypass that feeds the coil full power only when the starter is engaged-it's common with the large stud that feeds the starter. <br><br>The small Red/blue wire is the "control" wire from the igniton key switch- 12v only when the key is turned to "start".<br><br>The solenoid does NOT have a ground wire of any type -it's grounded through it's metal body and mounting bracket to whatever it's bolted to. If for some reason it's not bolted to some grounded metal body part, it won't work right. Move it to the core support, firewall, innder fender panel, whatever- as long as it's metal and it's grounded to the frame (and thus, the battery " - " post. <br><br>You should be able to remove the brown wire from the solenoid without really affecting how your truck starts- it depends (on the timing, the carb, the plugs, the battery...)<br><br>If you've got a truck that's hard to start when really cold or really hot, add a simple ground strap from the engine block to the frame-this'll fix all kinds of weird problems.

 

[edjolly]

This is a great thread, and very relevent to my current problem.<br>All my manuals show a resistor wire even with the duraspark setup, and I have this wire on my ignition. I also have a ground on the start circuit common to the module and the starter relay, and a 400 ohm short between the start circuit and the run circuit. I have to trace this down this weekend.<br>By the way, the Clymer's manual shows many excellent troubleshooting techniques for these systems, much better than anything in the Haynes or Factory shop manuals.<br>According to Clymer's I should have 70,000 ohms minimum between the start and run circuit and no grounds.<br>My questions:<br>1) ebronc says I can pull the ballast resistor and do away with it. Have you done this on a Duraspark, ebronc? I don't want to blow my module.<br>2) If I start digging through my dash harness, how long is the ballast resistor (red resistor wire)? How far back into the harness will I have to go to get the thing out?<br>3) I'm thinking my most likely culprit for my short between run and start is at the switch. By my schematics, this is the only place where they converge other than the module and starter relay, and I've isolated those. Otherwise the insulation is bad somewhere in the harness. Does anyone know of another problem location I should look?<br><br>TIA<br>Ed<br>

 

[ChiefDan]

Alright, my final observations.<br>The NAPA ST85 starter solenoid does require ground on the second lug on the front of the unit. Just connecting 12V to one of the lugs will not close the connection allowing 12V to go to the starter. You must have ground on the 2nd lug. I verified this by disconnecting everything, then applying 12V and ground and I could hear the switch throw inside.<br>My other main observation, I HATE THAT STUPID IGNITION SWITCH ASSEMBLY. Jeez it is a pain to get back together in the dash.