The Stovebolt Site Forums The Shop Area The Electrical Bay E Gremlin: Dead Ign Circuit and Grounding Problem

'49 3600 12V Generator 261 SM420

I was installing a radio, key switch and new gas tank and sender. Got the first and the last done, didn't make it to the key switch when the following symptoms popped up (not immediately related to any install):

1. High amperage draw even with the key off. On our crude Ammeter gauges it looks about equivalent to the headlights (high beam) on. So this shows up with the key off and simply having the battery connected. No obvious grounding events (no spark, no heat, no smoke). Leave the (new) battery connected and it will quickly discharge over about 2-3 hours.

2. The amp draw showed up first, and was shortly followed (2-3 starts later) by a dead ignition circuit: no spark at the (ancient) coil or plugs. So I changed the coil, points (my 13 y.o. had left the ignition on overnight), and condenser . Still no electrons at either the coil high tension lead or spark plugs.

3. I disconnected the new radio addition to the key switch, no difference. Then just for fun I disconnected everything from the old (a generic NAPA) key switch. Still no difference on the battery discharge. Something is drawing without the key on.

My first thought was that the ignition circuit from the key switch was grounding in the key switch, but that's not right (since the discharge is still happening with the wires removed from the key switch). Keep in mind that at least twice I was able to start the truck and run it, with the big discharge, before it all died. I have a Bosch RPM gauge that runs off the coil that went dead (showed 0 RPM) two runs before the whole ignition quit.

Starter motor and battery will still crank until the cows come home.

My To-Do list includes eventually adding a new wiring harness, this thing has the typical original, hacked up, crusty harness. So there's no love lost there or anything worth saving. If I wanted to run power to the coil/ignition would that be a simple matter of adding a new wire from the key to the distributor? I'm good with motors but not so much with electrons . . .

You did have the right idea. Disconnecting things, one at a time. I guess by RPM gauge you mean a Tachometer? Disconnect that. I am guessing it's a stuck VR so buy a 10si alternator and install it. Throw way generator, VR and all it's wiring, Get rid of the ammeter. We can help you install the alternator and a voltmeter. This will get rid of a lot of trouble you are having and future troubles, for very little money. If there is a draw after that, we will help you find it. But with what you have now, it's too much trouble. Save up for a Painless or Speedway 12 circuit harness.

As you know, I've already recommended much of this back on Feb 19 at post #1398028 of your post.

I know I have given you advice you didn't ask for. You just had one question.

To actually address your post: After your story about various issues, you only asked one question. "If I wanted to run power to the coil/ignition would that be a simple matter of adding a new wire from the key to the distributor?" This is easy to answer but difficult as to which way to answer. Keeping in mind you are not good with electrics.

1. Disclaimer: You have a swapped 261 motor and now have 12V. I do not know what wiring was done by previous owners and by you. A stock 49 would have had a 216 or 235. I will assume you have a foot start with an on/off type of switch of some sort. I do not know of any accessories that may have been added to truck's electrics.

2. Stock 49 would have battery cable to starter button stud. The type of starter button used for 12V. It has a "side terminal". This button is mounted to the starter and is actuated by the foot lever.

3. You should have a ballast resistor on fire wall (white ceramic block). In your case, there should be two wires on coil positive. One from the starter button side terminal and one from one side of the ballast resistor. Then a wire from other side of ballast to Ignition switch "ON" terminal. (that terminal probably also has the gas gauge feed wire)

4. Back to the starter button stud: There should be a wire from that stud to one of the ammeter terminals. Then a wire from the other ammeter terminal to the ignition switch battery terminal.

Check to see all the above is wired like that. No other "wild" wires. No miswires. If you see something wrong, stop! and Report. If all looks good, then with ign sw off, check to see if ign sw batt terminal is hot, If it is, turn switch to "ON". Check that it's "on" terminal is hot. If it is, check that coil positive is hot. Turn off switch. Check for draw after switch is off. If you have a draw......
Take negative battery cable off of battery post. Take off battery wire on VR. Tape it up or tie it up away from anything. Put battery cable back on. Key OFF. Check for draw again. If you still have draw. take off cable again. Install VR battery wire. Report. If the draw goes away, it's the VR. Maybe generator brushes. I'm not sure. I don't like, or use, generators and VR's so don't I want to know about them. They are worthless, unnecessary electrical headaches.

BTW the answer to your question is NO.

When you turn the key on, the gas gauge along with the ignition coil should have power. So if the coil has no voltage does the gas gauge move?

T-Nix: The gas gauge does work when the key comes on.

Bartamos: thanks for the organized list of steps. Helps a lot. I will implement this afternoon and let you know what worked.

This truck has the original wiring harness as modified over the years by everyone but me. 12V, generator, stomp starter, original lighting fuse block, no accessories except for a goofy horn that's in-op, and now my radio addition. I concur on the alternator upgrade (and wiring harness), sometime this summer I hope.

I didn't get the whole checklist done yet, but removing the battery lead from the Voltage Regulator confirms that the VR is the source of the discharge. Where does that current go? Into the generator windings?

A quick look at the wiring on the firewall appears to be ok. Will have to spend more time checking in detail and continuity testing (all the color coding is long gone).

Didn't see anything that looked like a ceramic ballast resistor on the firewall. Can't post pics from my laptop, will see if I can upload from my phone

Ballast resistor can be mounted elsewhere. Just see if there are two wires to coil positive. See if you have side terminal starter button. That should take about 30 seconds.

Glad you may have found the drain. A power drain has to find ground so it's traveling thru the VR in a bad way and finding ground in a bad way. Voltage must have been getting "consumed" in the form of heat and not melting wires or blowing a fuse. Not sure. You would think the VR would be very hot. The 12V is turning the coils in the VR and the fields in the gen into heaters maybe. You are making me talk about VR's and Gens. I'm not your man for that. There is about .26¢ of scrap metal there.

Here is a side terminal starter switch, just in case you don’t know what they look like.

Here is a ballast resistor. Click This would have come with the 261 motor if 1955.2/1956 and up.
Does your coil say "externally resisted" or "external resistor required" on it?

I realize you are doing the best you can as time allows.

If you have two wires on coil positive terminal. Follow one to starter. Follow other to see where it goes. If you have only one, follow it.

There's two wires to the coil +, but one of those drives the tachometer, so only one wire. I have not seen anything looking like the ballast resistor pic/link you posted. The new coil does not require an external resistor. I hooked it up just like the old coil was, and discovered it was reversed polarity: wire from the starter went to - and the + wire went to the distributor. That won't stop it, but will make it less efficient at making quality sparks.

I'll get a better pic of the starter wiring tomorrow, but it does look similar to the side terminal pic Phak posted.

Thanks for the help guys!

A little more on ballast resisters: The wire from the starter to the coil, typically supplies 12 volts only when the starter is engaged. Once the engine starts, it runs on the power supplied by the ignition switch. When the industry switched from 6 volt to 12 volt systems, they installed a ballast resister between the ignition switch and the coil to cut down the amount of voltage supplied to the distributor and coil. Apparently, a full 12 volts going thru the points burned them up prematurely, so they added a resister to cut the voltage down a bit (approximately 9 volts).

In your case, a previous owner (or shop) did not understand how the system worked and thought they could eliminate the ballast resister by using a resistance coil. In theory this works and some owners have done this and have no issues especially if you live in a warm temperature. I, who live in the north, want that extra voltage when I start my truck in cold temperatures.

Your in good hands with bartamos guiding you thru your issue but I just wanted to give you more information so you could make an educated decision as to reverting back to the ballast resister system or keeping what you have!

Is the ballast resistor doing something different than the external resistor that used to come with a coil? Or do they serve the same purpose? My understanding is that they were able to eliminate the external coil resistor by putting more windings inside the coil.

They serve the same purpose but is was a bad idea in my opinion. The 261 used a firewall mount ballast resistor. Many trucks and cars used the ceramic ballast. Some used the internal resisted coil and some used a resistance length of wire. Both of the other ideas area a PITA. The extra windings in the bottom of the coil you have get hot and contribute to the overall coil heat/failure. Coils get hot. The ceramic version gets real real hot also, but it's out in the moving air and on ceramic. Lasts forever and easy to wire. Not many vehicles used the internal res. coil. Tractors, Chrysler....If you buy another coil, DO NOT buy the internally resisted type. For now, you should be OK.

1. Did you check all the wiring I mentioned yet?
2. You don't need to hook up VR or gen to start motor just for a test.

Here’s a clear pic of the starter, no lead going to the coil. So this coil is just running off of the keyed circuit, no extra volts from the starter when first firing up.

Despite the backwards wired coil, this whole shooting match was running. Failure mode was: first the Tach, then the VR (big drain with battery hooked up and key off), then the spark stopped.

The connections on the "3-position-on/off" key switch (a generic one from NAPA from 30 years ago), have only: 1. Battery wire in, 2. A mangy wire running (very tight) to the Fan/Heater switch (I suspect this switch is being used as a terminal/connection block, not original wiring plan I think), 3. A third mangy wire (looks just like #2) that disappears into a repaired, original bundle that crosses through the firewall. Color coding is all gone, but likely this 3rd wire is my ignition wire to the coil? It's not outright burnt anywhere, but it sure ain't a poster child for continuity.

Don't need side terminal with internally resisted coil. If you still have no spark, I will need to ask you some serious questions. You have asked if a certain wire is ignition to coil. You will need to determine that before moving forward. Report to us.

1. Exactly where is negative battery cable connected?
2. How have you determined "no spark". Explain in detail.
3. I see mangy, greasy, dirty, corroded cable ends attached to starter, coil and most likely battery posts. Those will have to be fixed ASAP. Shinny clean, whether power or ground connection.
4. What is the part number of the new coil? How do you know it is internally resisted? Pic of markings?

These answers will enable next questions. Short steps to begin troubleshooting once we are sure of the actual issue. Some questions may seem silly but they have a purpose. Some seem like we don't trust you. We can't, done that, been burnt. Verification is needed. No offence. NOT personal. But something is wrong. Sometimes it's a bad part. Miswire. Sometimes the poster is assuming or misinterpreting, etc. We have to catch all.

Shiny? Clean?? Sheesh! The Standards in this joint! :-P Yeah I've been slowly bringing this old truck back and still have a long way to go.

No spark: pulled #1 spark plug lead and cranked engine, no spark from lead to plug. Pulled coil HT lead and cranked, no spark to engine block (1/4" away).

Negative battery terminal is connected to the frame under the floorboards immediately adjacent to battery. Prior owner used a red cable for this negative ground. Hmmm. Engine is grounded to the frame.

Don't know the part number of the new coil. NAPA issue and labeled Internal Resistor on the outside of the coil. The old coil was leaking oil and still had its external resistor but with the lead clipped off. Again, hmmmm ....

Tomorrow I'll run a long wire around from the coil into the cab and check continuity of the two wires on the ignition switch. I should probably just replace it with new to get me by until I do the new wiring harness for the entire truck. The wire to the fan/heater works (fan blows), so it's really just the other one that needs checking (or outright replacement).

On the coil, I see a green wire and a dark wire on the coil positive. I guess the green goes to the RPM meter? Did you have spark after that was installed? I recommend taking that wire off and rechecking spark. The proper way to check spark with a plug wire is to take plug out, keep wire connected to plug and touch threads of plug to clean bare metal. Plug gap hanging away from metal and watch for spark across the plug it's self during crank. This checks everything at once. Your ground, the plug wire, the plug wire connection, the plug and the gap of plug.

You don't test the HT of the coil at 1/4" from ground. You test it at .030-.040 (like a spark plug gap) to a GOOD BARE METAL SPOT.... an you are testing the distributor end of the HT lead. Leaving the coil end attached to coil.

You must also see no voltage with key off and then see about 12V voltage with key on and about 12V voltage during crank, all at the coil positive terminal.

The quickest way to be sure coil is getting full 12V is to add a jumper from battery pos to coil pos and test spark. If motor starts, you will have to disconnect that jumper to stop motor. Be SURE that RPM meter is DISCONNETED at coil.

Just to be clear and us the correct wording, you said the sequence of events ended in no spark. You say there is no spark.
Does the motor fire at all? Nothing? No noise? No backfire? No momentary ignition? Did you dribble a little gas down carb and try?

No fire at all, just crank and crank. But to answer your questions:

The green wire in the pic does go to the Tach. And the engine ran fine for about 600 miles hooked up that way. I guess what you're getting at though, is that the power to the coil could be grounding through the Tach? Hadn't thought of that. I will disconnect it and see what happens. Keep in mind that the engine ran fine for a long time, then the Tachometer died, then two or three starts later the engine would no longer start. So the lack of spark and the Tach are not perfectly correlated.

The other dark wire you see connecting to the same terminal as the Tach is actually a Red wire and it connects to the distributor. Pretty messed up, and this is on the negative terminal of the coil (distributor wire and tachometer wire). I don't know why the prior owner was into using Red for ground everywhere (the battery ground is also red). Anyway, a coil will function reversed (not as well), but I'll swap things back to the proper locations: negative to distributor and positive gets the lead from the ignition and the tachometer (after the truck runs with the tach disconnected).

I'll try your jumper from battery positive to coil positive tomorrow and let you know what happens. On the spark plug test I was using one of those inline tester gizmos for the spark plug lead, and for the coil lead I was holding the HT wire out of the coil next to the head; touching, close, far away and it produced nothing.

Yes, I was thinking the RPM meter was grounding the coil. It could be the problem since it died or it died because connected to wrong coil terminal. I hope you are saying that when HT wire was tested that it was still IN THE COIL and the other distributor end was the one near metal to test for spark.
It will be a miracle if points and condenser and coil are not screwed up. 600 miles hooked up bassackwards.

I can tell you have the situation in hand and are thinking what I'm thinking.

Someone thought it is positive ground?

Sooooo .... got the coil wired up correctly (+ wire from ignition, - wire to distributor, left the tachometer wire off), and new points and condenser. Also installed the new (made in USA!) voltage regulator.

No battery drain when connecting the battery ground cable, so the fused VR problem is solved. Engine would crank fine but still wouldn’t fire and no spark. Tried Bartamos’ idea of jumping power direct from the battery positive terminal to the + terminal on the coil and the engine started on the very first spin. It’s running a bit rough though, like I didn’t set the points right or the spark advance is off. Have to double check both, before all this started the 261 was purring like a kitten.

Next step is to get under the dash and see if I can find the continuity break in the ignition wire. After the key switch, where does the ignition wire go? Straight to the coil or does it stop anywhere along the way?

Btw, took the cover off the old VR and couldn’t see anything wrong, but it’s obviously bad. The new one cures the power drain and is charging the battery just fine.

Test what you have first as I said. Take off jumper. Test coil pos terminal for hot. Ignition off, then ignition on. Baseline test. Probably you will find no power in either switch mode
.
Answer. In your case, wire from ignition "On" goes directly to coil. I don't know what it really does on your truck.

After coil test at it's pos teminal, next test:

Confirm continuity with mangy coil wire going to IGN Sw.
Confirm it is going to "ON/Run" terminal of Ign Sw.
Confirm "ON" terminal of Ign Sw is cold with switch off and hot when on.

If switch is operating correctly, you can just add a new wire to coil and abandon mangy wire.
Obviously you have a bad wire, bad connection or bad switch, BUT you did say gas gauge comes on. I assume it's wired to same "On" terminal.....SOooooooooooo......

Duh ... left the number 1 spark plug wire loose. Purrs like a well mannered kitten now.

Awesome.

I checked continuity on the key switch at the very beginning of this endeavor; I did it because the terminals weren't clearly marked and I was curious about the two "On" positions; one to the left and one to the right. As it turned out, either left or right "On" connected both output terminals. So one terminal goes to battery and the other two terminals light up whatever you want no matter if you turn the key right or left. This is a generic NAPA key switch. I found it strange that it worked that way: two possible On positions and both were All On, but that sounds like a common oddity with old AD key switches.

The replacement key switch I bought from Classic Parts is a reproduction (the one with the lightbulb) and it also has two "All On" positions. I wasn't able to install that switch since it didn't come with a bezel (and the NAPA bezel won't work). Most likely it was me messing with the old, crusty wires that failed the Ignition wire, but for the life of me I can't see where.

I did make those other tests, + at the coil was not hot no matter the key position, and my suspected ignition wire was not showing continuity with the coil. I put the jumper to the coil on the key switch so it's easy on/off and ran the wire through the firewall. That should tide things over for now, and I'm going to start shopping for a new wire harness.

Issue closed.

Great to hear!