From what I read, you do not want to do that. They were talking about how wiring it that way can damage the starter by "starter run on," approximately 2 seconds after the vehicle starts because of remaining voltage in the wire. I'm just quoting a post I read on full size bronco, please don't shoot the messenger. "DO NOT USE THE BUS BAR or jumper the large Starter Solenoid Main Post to the small Solenoid Start Post in an attempt to eliminate the need for a separate 12v Start Wire."

 

Okay, that's slightly different than I was thinking, but it doesn't really change much of anything for testing. I thought you had wired the setup as seen in post #119, with a jumper to the solenoid control wire.

Your present setup should work just fine. If anything, it's overkill, as you've got the massive fender-mounted relay (originally designed to handle several hundred amps) now handling a much smaller current (a dozen or so amps?) for the solenoid on your new starter.

The only thing we haven't really tested is that 12v command (from the output side of the fender-mounted relay) feeding the solenoid on the starter. In theory, if there was a restriction somewhere in that part of the control circuit, the solenoid would get less than full voltage. This would reduce the clamping force on the big contacts inside the solenoid and increase the resistance, but such a fault would have shown up in the voltage drop test when you put your meter lead downstream on the braided cable going into the starter body.

For S&G, you can run a voltage drop test of that circuit. Put your meter's (+) lead on the battery's (+) terminal. Put (-) lead on the small stud on the starter solenoid. Disable the ignition and crank the starter for about 5 seconds. If the circuit is good, you will see less than 0.5VDC with the circuit under load. Remember, the closer to 0.0 the better. This tests the main contacts of the fender-mounted starter relay and the wire from there to the solenoid. I highly doubt you'll find any fault there, but it would only take a few minutes to rule out.

 

That is a myth. As soon as power is cut to the starters solenoid the voltage is cut, and it retracts the drive out of the fly wheel. the speed of this is not far off the speed of light.

Additionally the starter drive is an overrunning clutch so even if stays engaged it just over runs much like if you hold key on for to long. There is no way for the starter to be driven by the fly wheel to generate voltage to keep it engaged.

If you use the fender mounted mounted relay to switch the control voltage for the starter solenoid you may very well no get a clean contact as it is designed to switch high amperage loads and uses that high amperage to help make the contact clean. Using it to switch the low draw starter solinoid could result in it not getting get full voltage to the starter solenoid and not getting a clean contact in it's relay and end up with reduced voltage to the starter resulting in slow cranking speeds and tearing up starter drives.

This how Ford for decades on tens a millions vehicles wired solenoid actuated starters. If there was a reliability issue with this it would have been done this way from the factory.

If you do not want to use a jumper bar on the starter then run the start/crank wire directly to the start stud on the starter. DO NOT switch it with the fender mounted starter relay.

 

One question about running the small start/crank wire directly to the small stud at the solenoid on the starter. I get how that is better, but what about the I terminal on the fender-mounted relay? This is a 460 truck, so I think it will have some stuff (fuel pump?) controlled by the I terminal. What would be the best way to handle those circuits?

 

There are two types of solenoids, the 4 post and the three. I run mechanical pump so I only use three, but it is setup for 4. If I'm basically not been using that solenoid, what is now its purpose?

Good idea on checking the solenoid while cranking to make sure that signal voltage isn't lost therefore shutting down the starter.

 

I've got to admit I'm about out of ideas. I've got another Hail Mary for ya, but that's about it. Other than that, you may have to spend some money to find the source of the fault. Any by "spend some money", I mean try some genuine Motorcraft parts.


Not really needed. Remember, other people have successfully done this upgrade. You're not some pioneer exploring uncharted waters. Yours should work, too, but there's some variable we just haven't determined yet that is causing your system to misbehave. More later on why your particular example may be different...


Yes and no. Definitely keep your battery. Too much available amperage is never a problem. Your battery is maintaining adequate voltage under load, so no need to mess with that. More battery capacity is going to aggravate any marginal fault and make it more apparent during testing, so don't take a step back there.

Do you still have the original factory-style starter? If so, why did you upgrade to the hi-torque? Were you having slow cranking issues then, or was it a preemptive kind of upgrade? If the old starter was working fine and you still have it, I'd definitely swap it back and see what happens.

Good luck getting everyone to agree, but the quality of your conversion parts is the one thing that keeps grabbing my attention. You've tested the snot out of everything else. Is it a 100% slamdunk conviction that genuine Motorcraft parts will fix it? No, but it's more like the uneasy feeling a guy gets when his wife suddenly starts working late, gets invited on weekend business trips with her boss, and tells the kids to address you by your first name instead of "Dad".

A few more random thoughts and questions as I climb down from my Motorcraft soapbox:


#7) After topping off the battery with your fancy new charger (I'm jealous, by the way), has the slow cranking returned? I'm talking soon after unhooking the charger, so you know the battery is fully charged. One variable we haven't really addressed yet is if your charging system is up to snuff. If the cranking speed was normal for a little while after an external charge, but then acted up after driving, your charging system is suspect. If the slow cranking happened after the truck sat for at least a few hours, you may have a slow battery drain. I know there's a lot of information flying back and forth right now, but the timing when the fault occurs is VERY important. To recap, if the slow cranking (no matter how intermittent) happens soon after an external charge, you've got a starter circuit problem. If the slow cranking does NOT happen after an external charge, you've got a charging and/or battery drain problem. And remember, all this time I've been pestering you to disable the ignition for testing to rule out that possibility for now.

#8) When you did the voltage drop tests on the big cables, how did you attach the meter leads to the battery posts? I highly recommend clipping the leads to a sheet metal screw driven into each post. If you hooked onto the battery terminal itself, you'd have missed testing the highly important connections to the battery posts.

 

Okay, a slow crank after sitting overnight, and then again shortly after driving. This is starting to point towards a charging system problem and possibly a battery drain, too. Could it be related to ignition timing, too? Who knows, but if at all possible, quickly disable the ignition and see if cranking speed returns to normal. Yeah, I know it's a pain, but it's very important.

Here's the charging system checkout, post #12:


https://www.ford-trucks.com/forums/1...egulators.html

I'm going to repeat my earlier recommendation to get a cheap digital voltmeter that plugs into the lighter socket. This will help you keep an eye on the charging system and the available battery voltage before and during each start. Just don't forget to unplug it when the engine is off to avoid draining the battery.

 

If you have the 12V ignition start lead on the I on the relay you have to retain that.

Then it becomes bit more complicated.n And you have to retain the Ford Starter relay.

It will require the addition of Diode capable of handling the amp draw of the Starter solenoid in the feed to the the starter solenoid. As show below.

This is to prevent back feeding to the ignition module when the field in the solenoid collapses when the key is shut off.

Some say to add it in the line going to the Ignition. I do not agree with this for several reasons.

1. You are cutting up the factory harness. Adding it in to the add on wiring leaves the factory harness intact.
2. The diode is usually then sized to handle the draw of the ignition which is quite low, the small of diode will not properly protect the induced voltage from field collapse in the starter solinoid.
3. If that diode craps out you may have intermittent hard start and not know why.

4. That is the cheap *** way of doing it.

 

This jumper is now the feed to the starters solinoid.

When the starter gets power from the starter relay that power is jumped to the Starters solenoid to engage the starter drive and close those relay contacts. It's not a great diagram as the starter solenoid should have 3 studs

1. Battery power
2. Solenoid switched Power out to starter motor
3. Power to solenoid.

 

Ok time to check to see if you are getting a full 12V to the coil and igntion box during crank.

If you are not this could be part of the issue.
They can be wired one of 2 ways.

See below.

 

#9) One more idea, from the "Time-Consuming yet Inexpensive Although Not Necessarily Conclusive Troubleshooting Department":

For a week of normal driving, keep your battery charger connected overnight. Sure, it's a pain, but this will provide another big clue without spending any money. If the starter is now fine every morning, you're hot on the trail. Even more so if the problem only happens after driving for a while, but not soon after a charge.

 

Was able to do some testing tonight. Idle is around 1000rpm, and the voltage at the battery was around 12.5. I had my assistant take the idle up to 2500rpm, it held right at around 12.75. After shutting off the truck with headlights on and heater blowing radio, etc, after about 20 seconds, voltage dropped to 12.00 volts. It was then I was able to see the slow crank. 3 times in a row it did it, dropped voltage to around 8 volts each time she hit the key. So there's a huge clue...

 

Wrote this post, went back out, battery was holding 12.3 volts, again slow crank...finally get her to fire up. Rev and hold engine about 3000rpm to get the alt charging for a few minutes. Shut it off and test better voltage, 12.3 volts...

i dont believe my alt is charging the battery. Which I would have proved by hooking it to a battery charger, letting it fully charge, and try starting it.

Which is what in doing now, hooking the charger to it till it's fully charged, and see if I have symptoms.

i will also change the wiring to the starter if still necessary, I just didn't want to test too many variables at one time.

 

Alt voltage is low, it should be between 13.5-14.5V when running.

 

h