Loss of power is back. Pulse generator? HELP

[curmudgeon]

Somebody may have mentioned this but is the cruise control connected only to the right side coil? If so the wire connected to the coil could be shorting out somewhere. Possibly you could disconnect both ends of the wire between the CC and the coil and check for short to ground. Or use a megger if you can get your hands on one. The short may only occur when the wiring is flexing during riding etc. You may have to flex the CC wire harness to find it. This is where a megger can help.
I would think that if the CC wiring is causing it you would have a CC problem during the time when the engine is having problems.

Phil

 

[Sink]

Pull the spark plug wires while you are riding to see if they are hot.... You should know pretty quickly if they are firing.... NO GLOVES! Don't tell me you are afraid of a little shock?

Sounds like these guys have a pretty good idea of what may be going on... better take their advice and not mine......

 

[crazykz]

It's could be the cruise wire because it's on the left coil which I believe is the trouble side. I've checked it though and it's solid. They make them really well and all that Ohm'd out good.

Soooo, I hooked up on LED to the input side of the coil. The problem is that the LED lights solid because there is 12V there with a negative pulse when the bike is running (I wasn't expecting that). We put a scope on it to see this. So we referenced the other side of the LED to switched 12V to get it to flash on the negative pulse. Works sweet. I have it rigged in there with rip cord, fused properly (just in case), and taped to the inner cowl so I can see it going down the road. If I lose the ignition pulse input to the cowl it will be solid on at idle instead of pulsing. We'll have to wait and see what happens.

For all you techies... yes there is a small mount of reverse current going back into the circuit but it's less than 20mA so if the circuit can't take that then it's a pretty piss poor ignition system.

Curt

 

[Coop]

Have you considered a R1200RT? They come in blue.

 

[crazykz]

I think you are asking for trouble.

The coil primary is driven by the ECM, a $750 part. There are no specs on the ECM outputs. No way of knowing if they can handle the extra load of the LED.

Do you think that the ECM would be protected from any issue where the coil could short or ground? I think so. You're right that it's an unknown and I guess a risk but it's a minuscule amount of current compared to the input current. This will tell me if the input goes to 12V or to ground or stays the same.

Curt

 

[curmudgeon]

Just guessing, but generally these devices are overload protected.

Phil

 

[Scooter]

Someone said that this is a waste spark type circuit and if one plug isn't sparking it might cause the other to not spark. Or if one of the output coil wires was bad and not sparking the plug it might cause the other to not spark also. Anyone have any more info on something like that?

Curt

IIRC, the circuit is called a waste spark because both plugs are firing simultaneously. Only one of the cylinders has the correct air-fuel mixture in it while the other one is getting rid of its exhaust. So if you're not getting spark to one cylinder you're not likely getting it to the other one also.

 

[Blrfl]

There are no specs on the ECM outputs. No way of knowing if they can handle the extra load of the LED.

A little math and common sense will answer that question:

The math:

• I was unable to find a figure in the service manual for the coil, but the primary of a typical ignition coils run in the range of 0.5 to 2.5Ω. Let's take the middle and use 1.5Ω. (Ω = Omega, the symbol for resistance in Ohms.)
• Let's say Curt's LED with its current-limiting resistor draws10 mA (0.010 A) at 12V. Ohm's law says Voltage = Current x Resistance (E=IR), so with some algebra its resistance comes out to 1200Ω.
• To calculate the resistance of the coil (R1) and LED (R2) in parallel, we apply the formula...
  Rt = 1 / ((1/R1) + (1/R2))​
  ...and find that Rt = 1 / ((1/1200) + (1/1.5)) = 1.4981Ω.
• Compare that to the coil's original 1.5Ω resistance and you'll find it makes a 0.12% difference in the resistance seen by the ECM.

The common sense:

• Systems that are mass-manufactured are designed to work without failure within the tolerances of the parts used.
• A typical mass-manufactured, random-wound inductor has a resistance tolerance of ?10%. A high-quality precision-wound inductor will achieve ?5%. In other words, even if Honda's ignition coils were precision parts (and I doubt they are), the resistance of any randomly-selected sample of our hypothetical 1.5Ω coil could be anywhere between 1.425Ω and 1.575Ω.

So I think the 0.12% difference Curt's LED is making falls well within the tolerance for manufacturing error, even for a precision part.

--Mark

 

[DeSTy]

Aside from anything else, connecting LED's to the primary side will show you nothing if the fault is in the coil. You will however, assume that it's ok as the fault was apparent but the LED was still lit.

You *need* to be monitoring the secondary side of the coil, and as an emergency fix, I'd go buy a very cheap and nasty inductive pickup timing light and tape it to your bike somewhere so you're monitoring the plug leads for output.

 

[crazykz]

Aside from anything else, connecting LED's to the primary side will show you nothing if the fault is in the coil. You will however, assume that it's ok as the fault was apparent but the LED was still lit.

You *need* to be monitoring the secondary side of the coil, and as an emergency fix, I'd go buy a very cheap and nasty inductive pickup timing light and tape it to your bike somewhere so you're monitoring the plug leads for output.

Checking for spark doesn't do me any good. I know when the bike fails that I'm not getting spark. All I'm trying to do is find out if I'm losing the ignition pulse or not. I can get a spark plug tester also IF I don't lose the ignition pulse. If all I had was a spark plug tester though I wouldn't know if the issue is before the coil, after the coil, or the coil itself.

Curt

 

[J Paul]

Don't forget this bike is fuel injected with 1 injector per cylinder. I don't know how Honda wires the injectors but there is the possibility of loosing one bank of injectors which would cause the same symptom. Jeff:

 

[DeSTy]

Checking for spark doesn't do me any good. I know when the bike fails that I'm not getting spark. All I'm trying to do is find out if I'm losing the ignition pulse or not. I can get a spark plug tester also IF I don't lose the ignition pulse. If all I had was a spark plug tester though I wouldn't know if the issue is before the coil, after the coil, or the coil itself.

Curt

I'd swap the coils from left to right and see if the fault moves or stays, then you'll know.

If you were loosing the ignition pulse from the pulse generator it would effect BOTH coils and would trigger an FI fault.

 

[crazykz]

Since I have the LED on the left bank if it happens again I'll have a good idea of where the issue is.

So far since I cleaned the input connectors along with the pigtail there for the cruise it has not happened again but I'm not that lucky for that to be it.

If it's going to happen again it will happen about the time I'm going to DNF on the Bonzai this weekend.

Curt

 

[crazykz]

We're out of here in the morning for our anniversary trip to the Hill Country. We'll say some prayers that your problems are now solved and that you do well in the rally.

Thanks. Let's pray that everyone on the rally are safe and have a great ride.

Thanks again for all the help.

Curt