Very much a newbie here. This is my first T and have had it stored for 8 yrs inside. Just rebuilt the carb from all of the great posts I found here. It fires right up and runs, jacked up as I have never driven one either, just want to get used to trying to smooth out the engine. Main problem I'm stuck, I can't turn it off! It starts with the key off or on. Pulled the switch out and checked wiring and to me it doesn't look right. Any advice as to which direction to go would be appreciated. I have photos of the wiring but not sure how to send them. Thanks
Turn off the gas. It will soon starve and stop running. Then disconnect battery ground terminal, and wait for a lot of good advice as to wiring
(Message edited by adave on April 02, 2016)
I did that, thanks only way I could stop it!
Dawn, I see by your profile yours a 1924.
Maybe this diagram will help you? If it starts up and run, maybe the wiring to the switch is not right. I could be even wired so it is "hot started".
If you have pictures but are having trouble posting them, email them to me at crazydart400 AT yahoo DOT com.
I might add, I would think it would be in your best interest to buy a complete new harness and a set of spark plug wires from one of the many vendors (Lang's, Snyders, Bob's Antiques, Bird Haven, etc.) Also add in a fuse per the diagram. New wiring will help to insure you don't have an accidental fire to your new toy, and the added fuse will also help as a backup.
I agree completely with Chad. I'd go one additional step and also get a new ignition switch.
Dawn you've had some electrical problems before judging from the cooked ammeter wire. Your switch might be internally cooked too. First thing to do is disconnect the wire going to the mag. It may already be damaged by feeding batt voltage to it but better safe than sorry. It looks like the batt wire (white tape from the meter) and the blue/yellow wire (the one with the different screw head) are on the wrong terminals. It's tough to tell because the terminals on the diagram don't match the layout on your switch.
It appears you have an extra wire added from the terminal block to the coil pack. looks like yellow with a black tracer. Do not turn the switch to mag with this wire attached as it could damage the mag.
Dawn, I sent you a PM regarding spark plug wires.
I agree with the others that it's time to replace those wiring harnesses, yours look worn out and could cause a short circuit.
Model Ts didn't come from the factory with any fuses to protect the wiring. Installing one is a good idea, see the diagram below. A 25 amp fuse should be installed in the yellow wire coming from the starter switch, as close to the starter switch as possible (point G on the diagram).
Good luck with your T!
Charlie, if you take Dawns picture and rotate it to the right 90 degrees (so the ammeter is on top), then it would match. What definitely is not matching are the wiring colors. And looking at the terminal block there could be more issues there too.
Dawn, I find the Texas T diagrams to be helpful, even if the color of your wires are not right. I would carefully trace each wire (especially concerning the ignition) and see if they are wired right.
I would also do as Charlie says and disconnect the wire at the mag post on top of the transmission cover (hogs head) for now.
It would also be advisable to at the very least buy the black owners manual, and second, the MTFCA electrical manual. We can help you, but sometimes reading and getting understanding of the sometimes quirks of a Model T are the best remedy too.
Maybe a bad switch - see:
As already mentioned Dawn, that extra wire running over the radiator support rod should not be there. That is applying battery constantly to the coilbox, bypassing your ignition switch function. That thick wire should be removed and you should replace the wiring harness as mentioned before.
If battery voltage is mistakenly applied to the wire that goes to the electrical terminal on top of the transmission case it will kill the magnetism of the magnets that are attached to the flywheel ... then you have a bigger problem.
As Chad said it would be a good idea to just disconnect the wire on top of the transmission and tape it up and tuck it out of the way just to make sure nothing bad does happen to the magnets ... you can then reconnect it when you install a new harness. It's not hard to do even if you've had no previous experience doing this. Just keep coming back here to ask for more help.
Thank you to all . I've disconnected that jumper to coil box. Runs with or without it so wasn't sure what it was for. The harness to the generator and lights seem to be in good order going to the wire block on bulkhead . The other harness I'm tracing down. It's apparent someone has messed with the wires because switch appears to me to be wired incorrectly.the amp wires I know are fried. Probably should have pulled switch panel out first, but supposedly it was sort of running before I got it, it started for a few minutes and I seem to remember pushing off the trailer. I'll take the switch off and check out the amp meter. Thank you again for your quick responses. The guy never told me the switch didn't work just the key was sloppy. I think I'll take that apart too, it's the pin type. Unless you think I'm heading in wrong direction. Thank you again!
Dawn, I agree with the others. The wiring needs to be replaced. The wires are worn out and will constantly cause problems and possibly cause the car to catch fire. I would not replace your original switch because the new ones are of bad quality and are unreliable. If it does not work properly it can easily be rebuilt. Also, the terminal insulators on the ammeter should be checked to insure that the studs are not shorted out.
Also, a fuse in the main battery wire is a good idea.
Looking a that fried wire on your ammeter looks like the post insulator washer has deteriorated, and likely shorted the wire to ground--might not be doing it now (probably isn't or you'd have other problems) but could easily do it later. Check the ammeter posts carefully and replace the insulating bits if needed. Or buy a new Fun Projects ammeter--pricey, BUT they're the best ones out there!)
Glad you removed that spark plug wire that was wrapped around the radiator rod--that was someone's idea of a hot wire job. And yes, you do need high-tension spark plug wires--although it will run with those wires as long as they aren't near any other wires--but don't get your fingers nearby when the motor is running--zaap!
Let us know how it's going!
here is how I did mine.
In the actual CORRECT Ford wiring there should only be one wire to each of the ammeter terminals. This is a common mistake. It isn't a bit deal but the often the INCORRECT routing shows the heavy YELLOW/BLACK wire from terminal number 1 on the firewall as connecting directly to the ammeter rather than connecting directly to the BAT terminal on the ignition switch as shown in Andre V. correct wiring setup. This has to do with getting the higher charge voltage from the generator to the actual loads being the headlights and coil box. The ammeter merely shows the charge or discharge current going to the battery. The car will run OK either way but the charge current from the generator is better sent to the loads directly to thus minimize the discharge of the battery and thus allow the generator to take the brunt of the current load whenever the generator is putting out current.
Also the correct main fuse size should be a 25 amp fuse since the wiring is designed to carry 20 amps normally. If you use a 20 amp fuse then you will likely get some nuisance blowing of the fuse even though nothing is wrong. Typically fuses are sized at 25% MORE than their normal CARRY current since their purpose is to sense and then stop EXCESSIVE currents caused by faults. It hurts when an incorrect wiring diagram is posted by those trying to help who are unaware that it isn't 100% accurate.
The second diagram posted would be more accurate if the timer showed a ROTOR device as an arrow with the center going to ground. This would then make it obvious why a coil will fire when one of its primary wires goes to battery and the other end goes to ground through the timer brush. Not showing the path to ground inside the timer might seem no big deal but to someone who is just looking at the diagram without any T experience might find it confusing and recently this question DID come up and it was a legit question with regard to the diagram omission of that data.
If you get to the point you want to have your switch repaired, contact
4396 LaVista Rd.
Tucker, GA 30084
He has been repairing switches for several years and does an excellent job.
The back of your switch looks perfect. Of course I can't see the tumbler assy, but I'd change nothing. I have all original parts in my car with no problem. What I would do is replace that wiring. Additionally, the terminal block is incorrect, and I'd put a correct one in its' place.
Still following the whole circuit through, took ignition switch apart cleaned all contacts and had to sand down the back plate . With a tester contacts are reading correctly on points.amp meter has new insulators now, inside wasn't fried just wires due to loose terminals everywhere. I'm used to working on golf carts and chargers for 20+ years, and import autos prior so I have little bit of knowledge there. One question I'm not certain on is the coil box. Does that act like multiple solenoilds with coils for resistance? I've been reading every book I get ahold of , just not sure of that. I've double checked everything so far on wiring. Starter button is fine from button to wire block. Checking for a new harness from key switch to wire block but in the meantime I made a new lead for the batt wire which was wrong and fried. 12g wire is what I normally use on 36v carts, will that be ok? Sorry for all the questions, you guys have been great. I'm learning more and more every day. Thank you all!!!!
Sounds like you're making good progress. Your free spark plug wires shipped out today, check your email for the tracking number.
Rather than describe the function of the coils here, I recommend that you read the three articles on "The Model T Ignition Coil" by Boggess and Patterson. Click on the link below, then select "Choose document" and scroll to the bottom of the list. The files are .pdf documents, you can download them to your computer for viewing at your leisure.
Sounds like you are on track. And a Thank You to Mark for his generosity.
12ga wire is fine, in fact the wire sizes are listed in the diagram above that Mark posted--not mine.
The coil box holds the 4 ignition coils. It is extremely similar to todays cars the use individual coils to fire the spark plugs on each cylinder. It is a very efficient design. Essentially, if you had one coil that went bad, you could still drive on three cylinders back home. Most people carry a spare coil or two with them just in case though.
Thank you Mark! I had read part 1 in its entirety before now know how to get part 2&3! All this advice has been greatly appreciated! Going back to reading and then down to work on it.
Any update, how is the work on the T coming along?
Being on the road I missed this discussion until now. Lots of good advice here, but if you detect any differences of opinion and wonder who's correct, go with John Regan. He's the inventor/maker of several excellent products most of us use, and knows electrical stuff inside out.
I agree with a lot of comments above, but not with the suggestion of immediately replacing the switch without checking it out. From what you say about your previous experience, I figured you could easily fix it yourself if necessary, and it appears that's just what you did.
Sorry for delay in getting back on here, pulled my shoulder out. Getting back on it today, putting fuse link in this morning and go it to give it a try again.
Have the fuse link in but I have a feeling we need to take out the starter button. After reading several other forums I think there should be insulators. Any input there? The post I put the fuse link it is not getting tight. The switch is the tab type any advice. I've been reviewing a lot of other posts and think maybe I need to remove switch and check out. Any advice would be greatly appreciated! You guys are great, thank you so much!
Thank you everyone! To many people to mention. Ignition switch is working perfectly after a rebuild. Followed all your advice except for replacing harnesses. Wanted to make sure it was going to operate first. Spark plug wires made a world of difference, Thank you again Mark Strange, hope you got our card. After installing new starter button it fires and runs first push. Thank you again!!!!
Yes, I got your card, thankyou! Glad it worked out for you.
Does the engine stop now when you turn the key to off? Sorry but I just had to ask !!
Go change the harness.
Here's another pic of switch wiring on my '26. The harness was made with the headlight wires all black so wire a multi meter I tagged them myself to keep track. Also I re-soldered the connectors before adding shrink tube.
George your photo shows the yellow and black going to the outside of the amp post. Andre's above shows his going to the inside of the amp. Does this make a difference? Wouldn't the amp gage show discharge instead of charging. Ive seen these both ways, even the diagrams show different placement. Thanks. Sam
Yes it does If the solid yellow wire(Thats coming from Gen.) is switched to the other side, then your Ammeter will show discharge rather then charge. It will still charge your battery but read wrong. Getting those wires switched has been a common problem with newbies on the forum trying to understand wires. This is what I started with my dad's screwy wires, till I updated with all new harnesses all around.
My ammeter was reading backwards when I bought my car from the previous owner.
At least the ammeter reading backwards is easy to diagnose and fix. With everything else shut off, turn the headlights on. If the ammeter needle swings to charge, then reverse the wires on the ammeter and button it up!
Another note on the wiring Schematics on this post. When I was doing my car last year, I ran across the wires basically correct but turned around. For example. One map shows the headlight wires as all black for both bright and dim. Another map shows the headlight wires with red and green tracers. Then on another shows the wires to the connection block on dash transposed. I'm not knocking these guys, all would work well, just human error and a little confusing at times, depending on what you are trying to do.
DON'T let DC voltage go to the mag post. Disconnect that wire until you have it all correct.
Thanks George and Mark, that is why I ask mine was reading charge when I turned headlights on. I switched and it is working fine. Just didn't know if that was the correct way to do it. Thanks for your input. Sam