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A Couple Basic Electrical Questions

Jeff10

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Hey,

I am looking to hook the solenoid from the propane system up to a switched power source.

I have read some posts that reference coming off the coil (if I read the threads correctly). The point was that power would be available during normal run and starting scenarios.

Is the coil the best place for this power source?

That leads to my second question.

I am attaching a picture an electrical component mounted on the passenger inner fender well. Once side of this device goes to the coil. The other side goes to two wires, one of which goes through the firewall (not a production hole) and the second goes to a wire on the harness which passes through the firewall on the far driver's side (looks to be a factory harness and grommet assembly.

I am going to relocate that electrical device so that I can mount the propane converter. I just would like to know what I am relocating. (It may also be the source of power for the propane solenoid.

Thanks

Jeff
 

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EFI Guy

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Looks like a ballast resistor to me.

I would use the coil wire to trigger a relay to control the propane setup. That way you don't have extra load through the IGN switch.
 

70_Steve

Old Guy
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Dec 13, 2002
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A good source for switched power (power with the key ON) in the engine compartment is wire 904. It's a Green w/Red Stripe wire that should go to the voltage regulator on the passenger side of the inner wheel well.

Also, as EFI Guy suggested, I would use that wire to power the coil of a relay, so the power to energize the propane solenoid doesn't come through the ignition switch.

Once side of this device goes to the coil. The other side goes to two wires, one of which goes through the firewall (not a production hole) and the second goes to a wire on the harness which passes through the firewall on the far driver's side (looks to be a factory harness and grommet assembly.
Also, as EFI Guy said, that component is a ballast resistor. It's used to limit the current through the coil during normal running.

That is not a factory part. Normally that ballast resistor is a length of wire coming from the ignition switch to a connector on the firewall. Not uncommon for that wire to get hot and fail, though.

Power to the coil is provided from two different sources. The "normal' source, while the engine is running normally is from the ignition switch. But during starting, that ballast resistor is bypassed, and power comes from the I terminal on the starter solenoid, to provide a bit hotter spark during starting.

So... That ballast resistor should have two wires on the side that goes to the coil. One, the wire to the coil. The other should come from the I terminal on the starter solenoid. Then the other end of the resistor is connected to the ignition switch.
 
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Jeff10

Jeff10

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Hi EFI Guy and Steve,

Thanks for the input.

I'll take a look again in the morning; but, I am pretty sure that the wire on the right side of the resistor goes to the coil. The two wires on the other side go through the firewall (although at two separate locations).

There is a second wire on same side of the coil as the red wire from the resistor. I believe it is going to the electric choke.

I don't want to mess things up.

Any suggestions on a particular relay to use? Is the thinking that the power for the relay would be switched source (on the right side of the resistor, as shown) and a ground. Then power from one battery, being that there is really no other place to pull power?

I just want to keep it easy; but, I want it right.

Thanks again for your input.

Jeff
 

Viperwolf1

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Be advised the 904 wire is not hot in START. (discovered that after a long day of EFI no-start troubleshooting) Only the red-blue coil wire is hot in START and RUN. I would also use a relay.
 

70_Steve

Old Guy
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Messages
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Be advised the 904 wire is not hot in START. (discovered that after a long day of EFI no-start troubleshooting) Only the red-blue coil wire is hot in START and RUN. I would also use a relay.
I guess I never noticed that. Although I never tested it, it looks like, as long as the stock wiring is in place, 904 will be backfed through the resistor wire when the key is in START. If the resistor wire (or a replacement wire) is not in place, it looks like you're correct. 904 will only be hot with the key ON.
 

70_Steve

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There is a second wire on same side of the coil as the red wire from the resistor. I believe it is going to the electric choke.
The stock Bronco choke was powered from the Stator connection on the alternator. That way, the choke is only getting power when the engine is running and the alternator is producing power. But that terminal has a reduced voltage... 8-9 Vdc if I remember...

I guess I feel uneasy powering "stuff" from the circuit that's providing power to the coil. I surely would not power anything, even the coil of a small relay or the choke, from the coil side of the ballast resistor. But.. since you have a ballast resistor, and not the stock resistor wire (you need to verify that!) then maybe it's not so bad.

Any suggestions on a particular relay to use? Is the thinking that the power for the relay would be switched source (on the right side of the resistor, as shown) and a ground. Then power from one battery, being that there is really no other place to pull power?
Google " Bosch style relay" and you'll find plenty. They're good for up to 30 amps I believe, and are available almost anywhere. Even the box auto parts stores carry them.

The coil of the relay will be connected to whatever switched source you decide on and ground. Those will be terminals 85 and 86 on the relay. Power for the solenoid will be connected to terminal 30, which is the Common of the switched contacts. The solenoid will be connected to terminal 87, the Normally Open contact.
RelayWiringGuide.jpg


I don't want to mess things up.
I don't like to mess things up either, but I do...
 

TwoDalesDad

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Jeff.....please give us a run down on your propane setup....i am very interested in doing the same conversion....
 
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Jeff10

Jeff10

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Steve and Viperwolf,

Thanks for all the great detail.

I'm sure the relay won't be a problem to install. I'm still not certain about the switched source. It sounds like Viperwolf is saying that it needs to come from the coil, and Steve is saying that might not be a good idea. (I know the coil on the propane solenoid needs to be on during cranking... or at least it should be on.)

And is probably true with a lot of vehicles that have been modified over the years, there has been a lot of add-on work done to the electrical system.

Any additional input on the switched source will be appreciated.

Thanks

Jeff
 
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Jeff10

Jeff10

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Hi TwoDalesDad,

Jeff.....please give us a run down on your propane setup....i am very interested in doing the same conversion....

I'll be happy to provide details.

It has been a lot more of a project than I thought it was going to be. The main difficulty was finding a tank. The Bronco is a standard cab, so the bed and the passenger compartment is open. The Bronco is driven on the street and off-road. Technically that meant that all of the valves needed to be vented to the outside. That ruled out forklift tanks. I eventually found a manifold tank setup that would work. There were valves to replace, and remote fill components to buy. I had to find a distributor that would sell the parts... there are liability issues. Making a long story a little shorter, the tank is installed, the remote fill system works, the tank has been filled to about 1/3 and there are no leaks.

Once I get the relay installed and wired, the rest should be plumbing.

I planned on taking pictures as I went along; but, things were running behind schedule. I will take pictures of the finished installation when complete.

My Dad was involved in Bill Stroppe's racing program when I was in high school. This project is as much of about those days as it is about helping the Bronco perform better off-road.

I'll keep you posted.

Jeff
 
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Jeff10

Jeff10

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Hi,

One more question...

The battery isolator has four or five wires attached to one terminal. I am looking to install a terminal strip to eliminate the mess on the lug. The ones that I have found are rated at 30A. Are those sufficient for the alternator output through the isolator?

Thanks

Jeff
 

70_Steve

Old Guy
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.

I'm sure the relay won't be a problem to install. I'm still not certain about the switched source. It sounds like Viperwolf is saying that it needs to come from the coil, and Steve is saying that might not be a good idea. (I know the coil on the propane solenoid needs to be on during cranking... or at least it should be on.)
My biggest concern is to NOT power anything from the coil side of the ballast resistor (except the coil!).

I would need to know exactly where the two wires on the left side of the ballast resistor go. Since there is a ballast resistor, "possibly" in place of the resistor wire, I can make some guesses as to where they go, which has already prompted my comment that possibly the ballast resistor was wired incorrectly. But without knowing for sure, I really can't make a recommendation...
 
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Jeff10

Jeff10

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Hi Viperwolf,

Be advised the 904 wire is not hot in START. (discovered that after a long day of EFI no-start troubleshooting) Only the red-blue coil wire is hot in START and RUN. I would also use a relay.

Being that the system has been modified, can you tell me where the red-blue coil wire originates?

Thanks

Jeff
 

Viperwolf1

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Hi Viperwolf,



Being that the system has been modified, can you tell me where the red-blue coil wire originates?

Thanks

Jeff

Sorry, I misspoke. I meant to say red-green wire. It come from the ignition switch.
 
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Jeff10

Jeff10

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Hey,

I have attached a couple crude sketches of the way the coil, ballast resistor, and battery isolator are wired.

I need to do some more research regarding the one red wire that goes back into the cab through the factory harness. I'm hoping I can find it in the service manual I have.

Any thoughts on the best way to power the propane solenoid yet?

Thanks

Jeff
 

Attachments

  • Coil and Balast Resistor Wiring 081513.pdf
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  • Battery Isolator Wiring Details 081513.pdf
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Steve83

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The battery isolator has four or five wires attached to one terminal.
That's the best way to make that connection.
Are those sufficient for the alternator output through the isolator?
Probably not, but it depends on exactly how you have the isolator wired, and what you're trying to accomplish. The best battery isolator is just a high-current (~300A) 12V relay (or 2) - that's how Ford did it in the early 80s.



Your 2nd PDF shows a breaker between the aux.batt. & the isolator - that shouldn't be there. How about posting clear photos instead? This thread explains the free method that I'm using, and a few others.
...can you tell me where the red-blue coil wire originates?
Some of your details (like connector shapes) are slightly different, but most of this applies to your truck's original wiring:

 
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Jeff10

Jeff10

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Hi Steve,

Thanks for the info. I'll take a look.

I'm afraid I am going to get tied up in the electrical that needs to be redone. Once I get the propane system installed, I'll post up pics of the electrical.

Thanks again.

Jeff
 

Viperwolf1

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Hey,

I have attached a couple crude sketches of the way the coil, ballast resistor, and battery isolator are wired.

I need to do some more research regarding the one red wire that goes back into the cab through the factory harness. I'm hoping I can find it in the service manual I have.

Any thoughts on the best way to power the propane solenoid yet?

Thanks

Jeff

The 2 red wires going to the resistor are redundant. Probably what happened is the original resistor wire (red in harness connector) burned and the external resistor and other red was added to make it work. Check out the condition of the original wire. Get rid of one of them.

White-red is oil pressure wire. Red-white is temp wire.

Isolator wiring looks ok. I agree, get rid of the circuit breaker.
 

DirtDonk

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...Your 2nd PDF shows a breaker between the aux.batt. & the isolator - that shouldn't be there...

What's the concern, out of curiosity?
Reason I ask is that using a circuit breaker is exactly how the isolator companies used to suggest you wire things.
Even to the point of including the breaker in their wiring kits.

Maybe they meant to put it between the alternator and the isolator, but their instructions made me think to use it between the isolator and Aux battery.
That's how I wired and ran mine for many years.

Paul
 

Viperwolf1

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I see no reason for it. It just limits the charge rate to the aux battery. I guess it could be protecting the isolator diodes from excess current if the aux battery was completely drained. But that would prevent you recharging it.
 
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