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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
Posted by Dustywolf
- April 15, 2025, 02:13:50 AMQuote from: 53Indian on April 14, 2025, 18:29:31 PMI'm sure you've tried this, but did the ecu fault code flash anything up?
Only in the past, and it was the fuel pump which I ended up replacing.
Posted by 53Indian
- April 14, 2025, 18:29:31 PMI'm sure you've tried this, but did the ecu fault code flash anything up?
Posted by Dustywolf
- April 10, 2025, 13:06:49 PMQuote from: Bucko on April 10, 2025, 12:54:01 PMJust thinking outside the box.... assuming you have the plugs contacting cylinders, maybe they spark once when you hit the starter but then due to the cranking vibration they lose contact and don't spark?
Good thought, but I have my buddy holding up the bike and pulling in clutch and holding the start button for me. I'm definitely making contact so that isn't it.
Such a weird issue.
Posted by Bucko
- April 10, 2025, 12:54:01 PMQuote from: Dustywolf on April 09, 2025, 23:53:53 PMI'd think that's part of my issue (having all the plugs out, or 2 at a time out) but that still does not really explain why it only sparks ONCE when I press the starter button.
It makes me think something is telling the ECU "hey, shut off spark."
Just thinking outside the box.... assuming you have the plugs contacting cylinders, maybe they spark once when you hit the starter but then due to the cranking vibration they lose contact and don't spark?
Posted by Dustywolf
- April 09, 2025, 23:53:53 PMQuote from: Bucko on April 09, 2025, 22:05:19 PMJust to clarify, the motorcycle 'ground' is 'floating' with respect to a dual fire coil output and is not strictly required for the plugs to fire (except in that it provides an electrical path for a pair of plugs in the same cylinder). The plugs don't fire from coil to ground, rather the complete fire path is from : coil > wire > plug 1 > motor > plug2 > wire > coil (the same coil) - interrupt any part of that path and neither plug fires.
If you have both plugs out, you need to connect them somehow in order for them to complete the circuit and spark.
I'd think that's part of my issue (having all the plugs out, or 2 at a time out) but that still does not really explain why it only sparks ONCE when I press the starter button.
It makes me think something is telling the ECU "hey, shut off spark."
Posted by Bucko
- April 09, 2025, 22:05:19 PMQuote from: Troll on April 09, 2025, 18:53:20 PMHere is the ign system wiring diagram. I still think you have flooded the engine. The waste spark system relies on at least one clean plug per coil in order to work. If there is no path to ground through an ionized air gap, the spark will not happen. Keep in mind, the spark jumps from the ground electrode to the positive electrode on one plug and from positive to ground on the other plug. All waste spark systems are like this, whether it's a Honda, a Harley, or a Chevrolet. It may be hard to visualize, but that's how it works.
Just to clarify, the motorcycle 'ground' is 'floating' with respect to a dual fire coil output and is not strictly required for the plugs to fire (except in that it provides an electrical path for a pair of plugs in the same cylinder). The plugs don't fire from coil to ground, rather the complete fire path is from : coil > wire > plug 1 > motor > plug2 > wire > coil (the same coil) - interrupt any part of that path and neither plug fires.
If you have both plugs out, you need to connect them somehow in order for them to complete the circuit and spark.
Posted by Dustywolf
- April 09, 2025, 19:02:13 PMQuote from: Troll on April 09, 2025, 18:53:20 PMHere is the ign system wiring diagram. I still think you have flooded the engine. The waste spark system relies on at least one clean plug per coil in order to work. If there is no path to ground through an ionized air gap, the spark will not happen. Keep in mind, the spark jumps from the ground electrode to the positive electrode on one plug and from positive to ground on the other plug. All waste spark systems are like this, whether it's a Honda, a Harley, or a Chevrolet. It may be hard to visualize, but that's how it works.
I am not flooding it... because the spark plugs are outside of the engine.
Its a super weird issue, especially now that it's acting different with the new VDS.
Posted by Troll
- April 09, 2025, 18:53:20 PMHere is the ign system wiring diagram. I still think you have flooded the engine. The waste spark system relies on at least one clean plug per coil in order to work. If there is no path to ground through an ionized air gap, the spark will not happen. Keep in mind, the spark jumps from the ground electrode to the positive electrode on one plug and from positive to ground on the other plug. All waste spark systems are like this, whether it's a Honda, a Harley, or a Chevrolet. It may be hard to visualize, but that's how it works.
Posted by 53Indian
- April 09, 2025, 18:20:38 PMNot a clue on this one.
No aftermarket accessories like alarm or ignition switch fitted that may have disturbed the wiring?
(I had a similar problem with mine but luckily I had another to swap parts off to eliminate the fault, saves needlessly replacing parts too - know anyone local with a VN1500?)
Also try putting a post on the Kawasaki Vulcan forum, there's some knowledgeable guys on there, as on here.
Posted by Dustywolf
- April 09, 2025, 15:16:51 PMGot the new VDS in, it changed the behavior of everything. The bike wouldn't spark at all with the kickstand down, etc as soon as I replaced the VDS. it would try to start before even with kickstand down and the clutch out.
Still have that spark issue. Clutch sensor works, neutral switch illuminates, kill switch works, fuel pump was working. Ignition switch working.
To reiterate, it will only spark ONCE when holding down the starter. If you keep holding down the starter button, it will not continue sparking.
Any ideas?