ak700x
New Member
I have 2014 NC700x and I was wondering if the wires from ECM to ignition coils should have 12 volts?
Wires from ECM to ignition coils
- Thread starter ak700x
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lootzyan
Well-Known Member
If you are analyzing the ignition circuit, the direction of the current is from the power source to the primary winding of the ignition coil and on to the ECU. So if you measure the voltage across the primary winding it should be the value of the power source. First, equal to the battery voltage, and after the engine starts, such as the charging voltage from the alternator. The ECM/PCM controls the operation of the primary ignition circuit. This simplified diagram may be helpful:
ak700x
New Member
Yes that's the diagram ive been using to trace the problem I'm having. I apologize for not been specific. Im trying find out if the Y/Bu and Bu/Y wires should have power instantly after start button is pressed and angine cranks over
lootzyan
Well-Known Member
The electrical voltage on the ignition coils is all the time when the ignition switch is turned on. The current flow is interrupted by the ECM/PCM. i.e. the ECM acts as a contact breaker which induces a high voltage in the coil to create a spark at the plugs.
ak700x
New Member
ok. There is to sets of wires going into the coils. Should both sets of wires have power?
lootzyan
Well-Known Member
If you measure the voltage with a simple multimeter then:
- when the ignition switch is turned on and the engine is not running, then the measured voltage on the Br wires will be the same as from the battery, and the voltage on the Bu/Y and Y/Bu wires will be slightly lower.
- after starting the engine, the voltage on the Br wires will be the same as the charging voltage. The voltage on the Bu/Y and Y/Bu wires will be intermittent - about 14V or 0V. But you can't see it with a simple digital meter because these voltage changes happen at least 10 times per second.
I don't know why you want to measure it. Ignition system failures are very rare.
- when the ignition switch is turned on and the engine is not running, then the measured voltage on the Br wires will be the same as from the battery, and the voltage on the Bu/Y and Y/Bu wires will be slightly lower.
- after starting the engine, the voltage on the Br wires will be the same as the charging voltage. The voltage on the Bu/Y and Y/Bu wires will be intermittent - about 14V or 0V. But you can't see it with a simple digital meter because these voltage changes happen at least 10 times per second.
I don't know why you want to measure it. Ignition system failures are very rare.
ak700x
New Member
Thanks. There is no power in Bu/Y and Y/Bu wires. I have no start problem. Engine gets fuel but no spark (in time to ignite the fuel) . I put test light on both sets of wires. Brown wires get power when i turn ignition on while fuel pump is priming. Once fuel pump is primed the power cuts off. When i hit start button power comes back to brown wires 3 seconds after i press start button. I pulled sparkplugs out and tested the spark. Spark is deleyed by 3 seconds. Becouse fuel gets in instanetely and spark is deleyed sparkplugs get flooded. Im trying figure out what is the couse of not having power in Bu/Y and Y/Bu wires.
Before this happened there was too much engine oil. Somone messed with my bike
Before this happened there was too much engine oil. Somone messed with my bike
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Has any engine work been done lately besides the over oil problem? Sometimes when people are working under the clutch cover they improperly assemble the CKP sensor. Typical fault is no spark at all, so that wouldn’t fit your symptoms.
Does your NC have an automatic or manual transmission?
Does your NC have an automatic or manual transmission?
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lootzyan
Well-Known Member
No offense but I am really confused what is your problem. Well, let's get one thing clear:
- "There is no power in Bu/Y and Y/Bu wires." - Of course there is power, but you can measure it with a voltmeter only when the circuit is open, as I described previously. Do not connect the 12V test light to the negative side of the ignition coil when trying to start the engine. The test light has a relatively low resistance which practically prevents the coil from inducing high voltage. The voltmeter can be connected because it has a very high internal resistance.
Here is a simple diagram of the ignition system, virtually unchanged for over 100 years.
If you have the Service Manual, section 5 describes testing the ignition system in some detail. But for some things they require special testing equipment, e.g. peak voltage adapter, CKP sensor (Crankshaft Position sensor) among others.
ak700x
New Member
It's manual transmition. There was no engine work done. I tested CKP sensor and has 430 ohms and about 2 volts
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ak700x
New Member
"when the ignition switch is turned on and the engine is not running, then the measured voltage on the Br wires will be the same as from the battery, and the voltage on the Bu/Y and Y/Bu wires will be slightly lower."
I mesured it with volt meter after reading your explanation and there is no power. Meter reads 0 volts with ignition switch on.
I tested CKP sensor and it did not require peak voltage adapter. To test the voltage on CKP sensor volt meter has to be in AC setting. That's what I learned lately. I'm jack of all trades. I have worked on cars all my life just don't know much about this particular problem. Never run into a problem like this
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lootzyan
Well-Known Member
Why do you need to measure the voltage on the negative terminal of the coil (the Bu/Y and Y/Bu wires)? If the primary winding of the coil is good then you can only measure the voltage on the negative side of the coil (the Bu/Y and Y/Bu wires) if the circuit is not closed to ground. I haven't measured this of course, but I presume the ECM keeps the circuit open before ignition to prevent battery drain.
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Moderate note: The “last reply” somehow required moderator approval. It has been approved and should now be visible.
lootzyan
Well-Known Member
Certainly measuring the DC voltage in the AC setting does not give the correct result. Forget about that kind of measurement.
Change the spark plug wires to new ones. If they have not been changed since 2014, in some climatic conditions they may lose their insulating capacity over time. Make sure all connections are clean and dry.
ak700x
New Member
Yes measuring the CKP sensor in AC setting does give the correct reading. There is no voltage reading in DC setting. There is 3 seconds delay on the signal going to the coils. Changing spark plug wires will not fix the delay. I have 95 yzf with 50K miles on it. Never changed spark plug wires at all. Runs just fine
Regarding spark plug wire replacement, it should be noted that OEM 2014 NC plug wires come only as integrated with the coil assembly. The plug wire caps are separate parts. I am not sure which climates would cause early demise of plug wires, but I have a Honda motorcycle 21 years old that has never had an ignition problem. Not saying it couldn’t happen, though.
lootzyan
Well-Known Member
Deterioration and degradation of insulation materials is a proven fact. Micro cracks in the ceramic insulator are certainly not visible, but the high voltage current has the ability to find them as the shortest path to ground. The insulating material of the wires is even more susceptible to degradation. The fact that it looks good and it is believed that the system functions efficiently does not mean that it is fully functional. I do not understand why deny the manufacturer's recommendations about the need to replace over time. These are preventive things if the ignition problem cannot be clearly located.
lootzyan
Well-Known Member
This statement that there is "a 3 second delay in the signal to the ignition coil" is rather dubious. Such a measurement could only be made with an oscilloscope meter due to the high frequency of changes in the ignition voltage value. The intended delay could only be programmed into the ECM, but there is no such thing. For what reason?
If the scenario is actually as you descibe, that you get spark but three seconds late, you might try holding the throttle wide open during the first three seconds of cranking. On many engines this action causes the EFI to deliver no fuel while the throttle is at WOT, which is useful for clearing flooded engines.
Do you know for the sure the update rate on your DVM?
ak700x
New Member
Thanks I will try that. What do you mean by DVM?
