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Posted by Bucko
- May 05, 2025, 19:42:08 PMQuote from: Troll on May 05, 2025, 18:47:15 PMFront and rear cylinder spark plugs are fired by one coil. The engine will run with only one coil functioning. The waste spark system works like this: The cylinder with the burnable charge will get the spark, since the mixture is conductive. The other cylinder has exhaust gas in it, which is not conductive. When the spark energy reaches the firing tip, it ionizes the gasses in the gap. If the mixture will burn, it will allow the spark to jump. This system has been used for around a hundred years. My Camaro has waste spark, just like the Drifter. Dual tower coils, one tower fires the plug on one side of the engine, and the other tower fires the plug on the opposite side. There are 3 dual tower coils. The newer systems use one coil per cylinder, dedicated to just that plug.
A wasted spark system works exactly the same way with one coil per two plugs on the same cylinder. The plugs fire every two strokes, one of which is on the compression stroke (fire) and one on the exhaust stroke (wasted). Each coil is triggered by separate, front and rear crank pickups which allows for fine-tuning of firing timing for each cylinder (otherwise, why would two crank pickups be required?)
In any case, here's a snip from the service manual: note how the coil marked '5' feeds both cylinder 1 plugs, and the coil marked '6' feeds both cylinder 2 plugs.
From Section 15-40 Electrical System of the 2001 Vulcan Drifer Service Manual.
Posted by Troll
- May 05, 2025, 18:47:15 PMFront and rear cylinder spark plugs are fired by one coil. The engine will run with only one coil functioning. The waste spark system works like this: The cylinder with the burnable charge will get the spark, since the mixture is conductive. The other cylinder has exhaust gas in it, which is not conductive. When the spark energy reaches the firing tip, it ionizes the gasses in the gap. If the mixture will burn, it will allow the spark to jump. This system has been used for around a hundred years. My Camaro has waste spark, just like the Drifter. Dual tower coils, one tower fires the plug on one side of the engine, and the other tower fires the plug on the opposite side. There are 3 dual tower coils. The newer systems use one coil per cylinder, dedicated to just that plug.
Posted by Bucko
- May 05, 2025, 13:12:00 PMQuote from: Troll on May 03, 2025, 16:06:21 PMThe twin plug system DOES NOT control one cylinder per coil, but rather one front and one rear. It should run on one coil, as long as it's splitting the spark between the cylinders. .
Perhaps I'm misunderstanding what you're saying, but the Vulcan1500 uses one coil to fire both plugs in the same cylinder (so it won't run properly, if at all, on one coil).
Posted by Dustywolf
- May 04, 2025, 02:57:40 AMQuote from: Troll on May 03, 2025, 16:06:21 PMMight seem an odd question, but....does this thing have a programmer on it? None of this makes any sense, unless there is a problem with the controller. Just another thought, because I can't see the bike: You wires the coils correctly? The twin plug system DOES NOT control one cylinder per coil, but rather one front and one rear. It should run on one coil, as long as it's splitting the spark between the cylinders. Decades ago, I dual plugged my 98 inch SuperGlide. Initially, I used two coils, one for the right side and one for the left. I replaced the ignition controller with a "single fire" system with 2 pickup coils. That let me run one coil for the rear cylinder, and one for the front. That allowed me to set the ign. timing separately for each cylinder, and use the full voltage from the coils to fire the plugs. The Drifter does not have a single fire system.
It does not have a programmer on it. The spark issue appears to be fully fixed, but now the fuel injectors are spraying too much fuel.
I think it may be the water temp sensor, it doesn't appear to have a vaccuum hooked up to the connection.
Posted by Troll
- May 03, 2025, 16:06:21 PMMight seem an odd question, but....does this thing have a programmer on it? None of this makes any sense, unless there is a problem with the controller. Just another thought, because I can't see the bike: You wires the coils correctly? The twin plug system DOES NOT control one cylinder per coil, but rather one front and one rear. It should run on one coil, as long as it's splitting the spark between the cylinders. Decades ago, I dual plugged my 98 inch SuperGlide. Initially, I used two coils, one for the right side and one for the left. I replaced the ignition controller with a "single fire" system with 2 pickup coils. That let me run one coil for the rear cylinder, and one for the front. That allowed me to set the ign. timing separately for each cylinder, and use the full voltage from the coils to fire the plugs. The Drifter does not have a single fire system.
Posted by Dustywolf
- May 03, 2025, 00:32:27 AMQuote from: chief on May 02, 2025, 16:10:09 PMECU test results?
No codes.
Posted by chief
- May 02, 2025, 16:10:09 PMECU test results?
Posted by Dustywolf
- May 02, 2025, 01:44:51 AMYep, so everything's working, bikes cranking great.. but it's still spraying too much fuel for the bike to start. Plugs are still dripping wet... we followed the vacuum diagram.
It feels like every time we fix one issue, another one comes right around the corner.
Posted by Bucko
- April 29, 2025, 18:06:39 PMIIRC, there's one in the first fiew pages of the service manual.
Posted by Dustywolf
- April 29, 2025, 05:02:28 AMGood news, we have spark but now no fuel spray.
Does anyone have a vaccuum hose diagram? Of so, please post it here.
Thanks!
Posted by Dustywolf
- April 21, 2025, 01:11:59 AMSo, good and bad news.
Map sensor vaccuum wasn't hooked up at all, got all new vaccuum lining and that fixed the fuel problem for the most part.
Now, I no longer have any spark. This is bizzare. Went from having strong consistent spark to none.
Will add, anytime I apply slight throttle while cranking it, the starter relay will click.
Anyone have any new ideas?
Posted by Dustywolf
- April 18, 2025, 14:38:11 PMQuote from: Troll on April 18, 2025, 14:17:02 PMFuel pressure regulator works to reduce the line pressure only after the engine starts. It's vacuum controlled. Stuck injectors spray fuel as soon as they have pressure applied to them Injector pulse width is controlled by the fuel map in the ecm, and the cell addresses vary by the coolant temperature reading.
Makes me think it has to do with my throttle position sensor... I'll test that according to manual specs
Posted by Troll
- April 18, 2025, 14:17:02 PMFuel pressure regulator works to reduce the line pressure only after the engine starts. It's vacuum controlled. Stuck injectors spray fuel as soon as they have pressure applied to them Injector pulse width is controlled by the fuel map in the ecm, and the cell addresses vary by the coolant temperature reading.
Posted by Dustywolf
- April 18, 2025, 00:04:06 AMUpdate: still figuring out the injector issue.
They do not appear to be leaky or stuck open, but when I try to start the bike they fire an unreasonable amount of gas. And there is a lot of pressure in the return line to the tank, could it be the pressure regulator?
Posted by Dustywolf
- April 16, 2025, 11:38:49 AMSo, I suppose I did a combination of things and now I have strong consistent spark.
Now, everytime I try and start it it'll gunshot or pop but won't full on start. I can see fuel mist leaving the pipes.
Plugs end up dripping wet, what do I do now?
Maybe my injectors are stuck open? Sure seems like it