Starter circuit wiring Question

[IDave]

These folks who have been having trouble starting their F and 2F engines lately on the forum brought to mind a question I have.

On my old F starter there is a side contact separate from the main leads that go to the battery, solenoid and ignition circuit. My mechanic friend tells me that this should have a wire connected to it and run up to the ignition (non-dizzy) side of the coil. What this wire does is send additional power to the coil, but only while the starter is engaged. This is intended to aid in starting (I won't say I understand well enough to say just how--a bigger spark at that point, I guess.)

Not one of the electrical diagrams for the LCs that I have seen has this connection marked. Yet, there is the contact on the starter, right where it should be.

When the battery is fully charged I don't seem to have any trouble starting without this wired up. But I wonder if, in a marginal weak battery situation, this would be sensible.

Is anyone else wired up this way? Is that a factory wiring scheme that just didn't make it into the diagrams? Is it a good idea?

Thanks

 

[Poser]

It is for bypassing the balast resistor, so that the coil gets 12V during start up ONLY!


Good luck!


-Steve

 

[toddslater]

On old points/condensor/ballast resistor ign systems, it is quite common to have a wire dedicated to give the coil the full 12v on initial start up. When you let the key go power will flow to the coil via the ballast resistor which will cut the voltage to the coil which in turn reduces the wear on the points. It's not 100% necessary. If your ign components weaken with age and starting becomes a more drawn out affair...then convert to full electronic (bwaaaa).....or run the 12 volt on start mode wire. I look at my crap to see if it is shown in any diagrams.

 

[toddslater]

Damn Poser's quick...and I am wordy !

 

[IDave]

Ok, guys. Thanks. Sounds like it is an optional circuit.

 

[Pin_Head]

They didn't come on earlier cruisers. I think it started in 74 or 75. The wire is shown in later diagrams:

http://www.ih8mud.com/tech/fj40_wiring_diagram.pdf

The voltage drops quite a bit during cranking, so the wire temprarily bypasses the ballast resistor only during cranking.

 

[hammerhead]

It can make a huge difference for cold starts. No need to ask how I know this (Experience).

 

[IDave]

Looks like black with white stripe wire in that later diagram. Now, I am thinking: what's a ballast resistor. I don't have one, do I?

Should this be something all of these guys, who can't get their engines started after driving fine for 2000 miles, be looking at?

 

[Landpimp]

Dave, the ballast resistor is a white ceramic block, with a terminal on each side. If your coil is for a non ballast you don't need it.

on my 45 lpb when I had the 75 dizzy on it, I swaped to a gear reduction starter and had to leave the wire to the coil off(the one that Poser speaks of) it made no difference in starting......it fired right up even when 20degs outside

Now I have a fj60 dizzy......


Oh and my stock 64 fj45LV does not have(never did) the ballast nor th ewire and it fire RIGHT up.

Looks like black with white stripe wire in that later diagram. Now, I am thinking: what's a ballast resistor. I don't have one, do I?

Should this be something all of these guys, who can't get their engines started after driving fine for 2000 miles, be looking at?

 

[toddslater]

Here is a lovely shot of my ballast resistor on my 73...well at least before it all came out and was upgraded to 1985 LC Ign. If your not running a ballast..that would definitely explain the ...no problems starting in cold weather for you. You could A) Do nothing....just keep an eye on your points as they will wear somewhat quicker. B) Install a ballast and the 12v "start up" only wire. C) Upgrade like I did and never worry about points, condensor or ballasts again.

Pin_Head,
I noticed it showed the wire on those tweener years as well. These were I think what they called the semi transistorized ign systems...obviously shown with an Ignitor. Do these semi trans systems require the 12v "start up" only wire ? I would have thought that would be one of the first items to go with an ignitor.

 

[Pin_Head]

All the ignitor does is switch the current on the ground side of the coil, so it has no impact on the voltage that the coil sees. If you have a ballast resistor and have trouble starting, you need the bypass. If you have a good battery, good cable connections and a good starter, you can get by without it, but is will be more reliable with the by pass.

 

[IDave]

Ahh-haah. Now, on my 65 FJ45, a PO added a ballast resistor (now that I know what you are talking about). It is clearly aftermarket (just screwed into the firewall next to the vin plate. I tryed bypassing it and the coil blew up (this was a while ago). That got me scared, so I put in an OEM coil, which was from my non-resistor FJ40 but tested fine. But I left the added ballast resistor back into the circuit after that. Perhaps with the OEM coil, I don't need the ballast resister, huh?

 

[Pin_Head]

Perhaps with the OEM coil, I don't need the ballast resister, huh?

It would depend on which OEM coil you have. If it has an internal resistor, you don't need another one; otherwise the coil will burn out.

 

[IDave]

It would depend on which OEM coil you have. If it has an internal resistor, you don't need another one; otherwise the coil will burn out.

Obviously, that's what happened when I bypassed the resistor and my PO's coil blew up. There were no markings on that coil either way. But I guess I should have guessed. Now I understand what happened. The replacement coil is from my FJ40, where there is no Ballast Resistor, so I'm confident I don't need one now.

Thanks, Charlie