• Hi Guest!
    If you appreciate British Car Forum and our 25 years of supporting British car enthusiasts with technical and anicdotal information, collected from our thousands of great members, please support us with a low-cost subscription. You can become a supporting member for less than the dues of most car clubs.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Spitfire Spark to Coil

Share this page

FlyingCat

FlyingCat

Jedi Hopeful
Country flag
Offline
I'm trying to bring my 1980 Triumph Spitfire (1500 federal) back from the dead. "Give my creature life! Life, I say!" But I digress. The starter is turning over, but I can't get a spark. I've got power going to the coil, and I've checked the ground, no problem there (maybe). The coil checks out, at least in theory, both primary and secondary, so there shouldn't be a problem there. I think I have the right wires going to the coil, though that's always a guess. The distributor may, or may not, be any good. (How do I test that?) I've tried the light test with the spark plug cables, and nothing there. Short of sacrificing a chicken, any suggestions?
 
Do you still have the original Lucas electronic ignition?
 
Do you have a spark at the points. The points could be fused. Do you have good wires, fully plugged in.
Hook a lightning rod up to it's brain and wait for a storm.
 
Do I remember from your earlier threads that this was a late model Spitfire with an aftermarket electronic ignition?

Coils seldom go bad. Likewise, distributors typically do not "fail", they slowly wear out. Tell us what ignition is there (post a picture of the distributor and coil if possible). Take a careful look at the coil and distributor noting the wire colors. Tell us what wire colors are on which coil and distributor terminals.

Once we know whether you have points or an electronic ignition, and once we know which wires are where, we will be able to walk you through checks and tests.
 
We don't get much lightning out here in the Pacific Northwest. As far as I can tell, there is no spark at the points. The plugs are new, and the wires seem to be in good condition (nothing visible), and everything is plugged in solid. I'm think it might be the coil.
 
Coil Wiring.jpg
IMG_3109.jpg


Unfortunately, I can't get these pictures to load unless they're on their sides. I blame it on Cybergnomes. The wire that is off to the right in the first pitcture is from the distributor, and it hooks up to the negative side of the coil. I don't trust any wire colours. The former owner, bless his heart, rearranged lots of things. But there you have it.
 
My mistake. That's a Delco points type distributor.

I cannot tell the wire colors. Obviously the green wire on coil + is not factory. Green wires on British cars are supposed to be switched, fused, 12V so the previous owner's color choice was bad. I also cannot tell if there are two or three wires on coil +.

Let's reduce the wiring to the minimum and then test for spark. In the steps below I'm asking you to remove all the non essential wires just in case one of them has a problem that is preventing you from getting a spark.

Mark each coil wire for position, then remove them and clean both the coil and wire terminals.

It looks like you have two white/black wires on coil -. One of those wires goes to the points inside the distributor. Make sure you connect that one back to coil -. The other white/black will go to an electronic tachometer. Tape that terminal off for now and do not connect it to anything.
Look carefully at the three wires that were on coil +. Tell us what those colors appear to be. There may be two white(ish) wires and MAYBE one yellow(ish) wire. Make sure NONE of the wires terminals are touching ground, then switch on the ignition and measure the voltage between each wire terminal and ground. One of those wires should read battery voltage (nominally 12.5V). Switch the ignition off and connect the 12V wire to coil +.

At this point you should have two wires on the coil... white/black on coil -, and a white(ish) wire on coil +.
Make sure the other end of the white/black wire goes to the distributor.

Remove the distributor cap. Turn the engine over until the points are seen to be closed.
Turn the ignition on.
While you use something to cast a shadow on the distributor, use a screwdriver to lever the points open while you watch the tips of the contact points. (Lever between the insulating heel block on the points and the distributor shaft. Do NOT let the screwdriver form a path to ground between the moving points arm and ground).

Each time you gently move the points arm to open the points you should see a small spark at the points. If you don't see a spark... let us know. If the spark is dim and orange, install a replacement condenser and try again. You should see a bluish spark which may be bright and strong but could be small. If you don't see any spark, double check which white/black wire is connected and remeasure the voltage on coil + with the ignition on. Let us know what you find.
 
Excellent information! At this point, I know I have major problems with the wiring throughout. However, I want to get it running before I worry too much whether the horns themself are bad, or if it's the wires to the horn switch, or the switch. With what you've told me here, I should be able to get a spark. And if I can get a spark, then I should be able to start it... given, of course, that I replace the fuel pump first. But that's for another day. I'll let you know.
 
I'm back from the garage, and so far, so good. I disconnected everything to the coil, isolated the + wire, a whitish / yellow wire, that, when grounded, showed 12.5V-ish on the multimeter. So I connected that one to the positive, and the one from the distributor to the negative side. Then I checked it for spark. I wasn't able to see if the spark jumped from the points, because every time I tried sticking a screwdriver in there it generally sparked everywhere, but I do know I have power going to the distributor. I could try moving the points arm with something that's totally plastic, but that will have to wait until tomorrow. As well, I tried checking the spark with a light test, but got nothing. Am I on the right track?

IMG_3193.jpg
 
You are on the right track.

The "sparks everywhere" is why I suggested using the screwdriver between the plastic heel block on the points arm and the distributor shaft. The heel block is an insulator. When the coil is supplied power, the spark is generated at the points and from the coil when the power is interrupted (when the points open).

If the spark is weak and/or orange, it could be the condenser is bad. You can typically install a new condenser without messing with the points gap. The inline tester you have can also be used. In general you will have better results with either test method if you can cast a shadow on the distributor and/or inline tester.

The white/yellow wire should NOT have power on it EXCEPT when you are turning the engine over on the starter. I'll try and be brief in the explanation.

On cars with a ballast ignition system the coil has lower resistance (1 to 2 Ohms across the primary terminals). There will be an external ballast resistor OR a "pinkish" resistor wire in series between the ignition switch and coil +. The yellowish wire goes between the starter solenoid and coil +. The idea is that the low resistance coil will be supplied higher voltage via the yellowish wire during cranking to develop a hotter spark. Once the engine starts, and the key is released to the run position, power to coil + is supplied at reduced voltage via the ballast resistor or a pinkish resistor wire. I believe some of the later Spitfires had minor variations to this so please remind us what year car you are working with.

You are getting close!
 
Mine is a 1980 federal 1500 with Delco-type points, and a Weber carb. I will try to isolate that spark again today. This time I'm going to use a toothbrush handle so I don't have to worry about sparking the wrong things. I'll let you know what I find there. As far as the inline tester goes, it's not showing me squat. I'm not sure the silly thing even works, as I've never seen it light up. Is there a way to test those? However, I've only tried it on one of my distributor wires. I'll try more than one today.

Ballast Resistor 02.jpg


There was a ballast resistor that came with my car. I'm not sure it actually belongs with my car, though, as there were several items (including a toaster oven) that came with my car that obviously (or not so obviously) didn't belong on a Spitfire. I've had some folks tell me I need that on my car, and others who say I don't. I'm so confused.

IMG_3195.jpg


Just to keep me up to speed, the condensor is the little round thing inside the distributor... right?

IMG_3196.jpg


There is also a little round thing hooked up next to the coil (in the center toward the top, with the black wire coming out of it) that is usually attached to the negative side of the coil. Is that a condensor, too? Do I need both? In that photo you can also see the two wires I currently have attached to the coil -- the red and white one that goes from - to the distributor, and the whitish / yellowish one that goes from + (assumedly) to the starter. Regardless, it's the one that tests for 12V on my multimeter.
 
I want to make sure I've got this right... on the left end of that blue thing below (the rotor?) are the points -- a little round metal circle that touches that other piece of metal that is connected to the brush that routinely comes in contact with the center. It's where that little round metal circle on the blue thing touches the other piece of metal that I'm trying to see a spark... right?

I know the red wire has power, and that the engine block is grounded. And I got other sparks while I was in there, but... I was supposed to be able to see a spark if I pried the blue thing up, causing a gap at the end, between the points, while the engine was on. I didn't see that spark. I had my garage pretty dark, so anything would've been noticed... but nothin'.

Hopefully I got all that right. If so (or if not), what next?

IMG_3199.jpg
 
I would go after DC conditions next, as it's easier to trace problems that way. With the points closed and ignition on, check the voltages from each side terminal on the coil to ground. The terminal that is wired to the distributor should be close to zero; the other terminal will be either close to 12v or around 6-8v.

Now turn the engine until the points open, and check again. Now you should find 12v on both coil terminals.

If the white wire isn't close to 12v in the first step, then there is a bad connection somewhere along the circuit back to the ignition switch and battery. Work backwards towards the battery until you find where the power "goes away".

If you don't find close to ground on the other terminal in the first step, there is an open circuit somewhere along the wire to the points, or the points themselves aren't making good contact. (Another distant possibility is that the plate under the points is not grounded). Keep checking along that path until you find where the open circuit is.

If the terminal wired to the points stays near ground in the 2nd step, then there is a short to ground somewhere. Or again a distant possibility is that the coil has gone open circuit. You can check that by disconnecting the wire and testing the terminal again.
 
Randall has given you good advice as he always does.

The red/white wire is not factory. Your pictures show that this is the wire which would normally be white/black. Once you get the engine started I suggest returning the wiring to standard colors so future troubleshooting will be easier. Wire in Lucas color codes is available by the meter from Britishwiring.com

Conduct the voltage measurements Randall suggested and let us know what you measured on the various wires.

Mark and disconnect the wires from the coil. Set your multimeter to measure Ohms and measure across the coil's low tension terminals. Let us know what resistance you find.

The cylinder with the black wire next to the coil is a capacitor/condenser. It is used as a noise filter for better radio reception. For now, disconnect the black wire. That will remove it from the ignition system during your troubleshooting. Once the engine is running you can connect it again.
 
Great ideas. I'm on it! Not necessarily that it solves any current problems, but I've discovered that the wires to my distributor are shot, bless their hearts. I remember when I was a kid. We used to go to this place called Fort Osage. It's in Sibley, Missouri, if you're ever in the neighborhood. Any rate, there was only one place in this whole "fort" that was actually the original fort. It was the bottom row of stones in the sub-basement of this one building. I'm feeling like that's what me car will be like when I'm done. You'll be hard pressed to find the original car.
 
The resistance on my coil is right at 1.7, well within range. And good call on the noise filter -- and it's good to know what that is. I'm not sure what I'm going to do about tunes with this car. I has an electric antennea (which probably doesn't work), but no radio. Was that antennea stock? And, yeah, getting all the wires to make sense makes sense. Good to know where I can find those colour combinations. It's definitely not something I can find at Lowe's.
 
A 1.7 Ohm coil is for a ballast ignition system. There are several tests ahead of you.

With the ignition switch in the run position, check again the voltage on the wires that were on coil +. You said it was the yellowish wire that was hot with the ignition on. That's not supposed to be the case. The yellowish wire is only supposed to be hot while the starter is operating. There should be a pinkish wire or a white wire on coil +. The pinkish wire (if present) takes the place of a ballast resistor. If there is no pinkish wire there should be a white wire coming from the ignition switch going to the area around the coil. With your 1.7 Ohm coil, the white wire would connect to the external ballast resistor. A wire from the other end of the ballast resistor would go to coil +. The yellowish wire would come from the starter solenoid and go to coil +. The idea is the yellowish wire provides more voltage/power to the coil while the engine is starting. Once the engine starts, there is no voltage on the yellowish wire and power to the coil is provided via the white wire and ballast resistor (or through the pinkish wire if fitted). Once you get comfortable with what is supposed to happen it will be easier to troubleshoot.
 
Not to worry, that's common with "restored" older cars. Kind of like George Washington's axe: the handle has been replaced 3 times and the head twice, but that's still "his" axe!

The antenna (and radio if any) would have been dealer-installed, I believe. The factory didn't normally install them on cars for export (except perhaps a self-export, where the owner picked up an export-spec car in the UK). The dealers were free to install as they saw fit; so it's possible they installed an electric antenna (though it seems unlikely to me).
 
Thanks! I've got all sorts of things to check. It might take me a couple of days, what with having a real job, but I'm on it.
 
Back
Top