Intermittent ignition problem while cranking engine during starting.

[Brillot2000]

DTC- Diagnostic Trouble Code.
MIL and FI and Check Engine are interchangeable names for the amber light on the dash.
CKP - Crank position sensor. If failed gives a 19 DTC (MIL flashes, 1 long & 9 short). It's common and most likely what is causing your problem.
CMP - Cam position sensor. If failed gives a 18 DTC (MIL flashes, 1 long & 8 short). Not common. Don't get confused with people abbreviating the Crank Position Sensor as CMP. CKP and CMP are not the same thing, but many are mis-naming the CKP as CMP.

If your CKP fails while running your engine dies.

If you have an active failure (MIL is on) you can do the Clutch released, in neutral, sidestand down trick and read the flashes on the MIL to determine the code for the failure. This is really easy. Don't turn the ignition switch off and back on before you do that or the MIL will clear if it was your CKP causing the failure code.

If you had a MIL but it has since cleared (due to it being an intermittent failure, or because you cycled the ignition switch) that code is stored in the ECM. You can read (& should reset) that code using the linked procedure or use the shop manual. Doing this is not as easy as reading active failure code. The shop manual is going to ask you to use a special test connector that you don't have.

Thanks for correcting me. I did not remember the exact details on the MIL Code flash combination for this issue. I am kind of like fix it and only remember the major details to the cuase of the issue. Too many other important things to remember these days.

Do recall this might be your post, Read & Reset MIL

I saw the diagnostic cable available for the NC700X for about $25. I am sure that one for this bike cannot be more than that.

 

[Turbo DV8]

Anybody feel up to playing a game of Conjecture?

Piecing together my experience, and some other observations here ...

I haven't heard any mention of one of these sensors failing while the engine is running. The failure occurs only when the engine has been warmed, and then is allowed to cool down a bit. If it cools down enough for it to begin working, and the engine starts, it would be warming back up. So why doesn't the sensor fail again as the sensor Rises back up in temperature, and cause the engine to stop running?

Pure conjecture, to be sure, but it makes one think to hear of so many of these failing, with exhibiting symptoms as I described, but not a single person saying that it failed while the engine was actually running. Curious.

 

[dnktng]

Anybody feel up to playing a game of Conjecture?

Piecing together my experience, and some other observations here ...

I haven't heard any mention of one of these sensors failing while the engine is running. The failure occurs only when the engine has been warmed, and then is allowed to cool down a bit. If it cools down enough for it to begin working, and the engine starts, it would be warming back up. So why doesn't the sensor fail again as the sensor Rises back up in temperature, and cause the engine to stop running?

Pure conjecture, to be sure, but it makes one think to hear of so many of these failing, with exhibiting symptoms as I described, but not a single person saying that it failed while the engine was actually running. Curious.

The area that the CKP sensor sits most likely gets hotter after the engine is turned off since the heat of the engine is no longer being dissipated by the coolant system and air flow when compared to riding down the road. I think there have been a few that put off replacing the sensor and it eventually started failing on hot days when stopped in traffic.

 

[Woodaddict]

First was 2 yrs ago(2016) in the mountains on a ride, with about 137,000 miles. this was the first start that it cranked and cranked. checked kill switch, key, gas cap, then it finally started and never had a problem again until just 3 weeks ago. had rode it, parked outside in hot sun, after about :30 wouldn't start back up. only after I took my truck to appt, then came home and tired again, it started 198,000

 

[Turbo DV8]

dnktng, in this thread and the link you provided on how to read and clear a code, repeated references are made to making sure the kill switch is "on." In your reply, you made reference to Simply proceed as if starting the bike. Which would mean the Killswitch should be in the Run position. When you say this, do you mean make sure the kill switch is in the Run position, or kill position? Because since the sensor is not actively faulting, to read the flashing code from the dashboard without having to use the jumper trick, and crank the engine for 10 seconds, if I put the side Stand Down and crank the engine with the kill switch in the Run position, the bike will start right away, and there's no way to crank it for 10 seconds, unless the kill switch is in the kill position. I'm not at home right now, otherwise I would just try things out. Thanks.

 

[dnktng]

http://www.nt-owners.org/forums/showthread.php?11365-Hey-Hey-its-crank-sensor-day!/page2

dnktng, in this thread and the link you provided on how to read and clear a code, repeated references are made to making sure the kill switch is "on." In your reply, you made reference to Simply proceed as if starting the bike. Which would mean the Killswitch should be in the Run position. When you say this, do you mean make sure the kill switch is in the Run position, or kill position? Because since the sensor is not actively faulting, to read the flashing code from the dashboard without having to use the jumper trick, and crank the engine for 10 seconds, if I put the side Stand Down and crank the engine with the kill switch in the Run position, the bike will start right away, and there's no way to crank it for 10 seconds, unless the kill switch is in the kill position. I'm not at home right now, otherwise I would just try things out. Thanks.

Yes, always have to have kill switch in run/on.
If the engine is starting normally I would assume you don't currently have a MIL, correct?
If you don't have a active fault, you won't have a MIL when you start the engine other than the self check when the ignition switch is turned on. But if you previously had a MIL the code for it is stored in the ECM. You will need to do the jumper trick to read codes stored in the ECM. You can only read active codes using the sidestand down trick. Follow How to read MIL codes stored in ECM in the Read & Reset Maintenance Indicating Light (MIL) link.

This post has some good explanations about how the CKP responds to failure and MILs.

 

[seagrass]

If the kill switch is in the kill position the starter motor is disabled so you cannot crank the engine (Australian model but I suspect the US model is the same)

Many vehicles have the same symptoms with a failing crank position sensor and they nearly always will not start after the vehicle sits for a while (after running for a period of time with the engine at normal temperature).

As dnktng has suggested, engines rise in temperature after stopping and this is what others have considered causes the crank position sensor to temporarily fail.

Some years ago in Australia, the V6 Holden (GM) commodore engine quite commonly had this fault and the solution was to simply open the bonnet and splash the sensor with some cool water. Once this was done the engine started up as normal.

Seagrass

 

[Turbo DV8]

My CX500, and cx650 turbo, would both spin the starter motor with the kill switch in the kill position, so that's why I thought the same thing would happen on this bike.

I do not currently have a MIL. I did notice that, after several attempts to start the engine, what I thought was the fuel injection lamp did start to Blink. But I did not know the significance of it, and therefore did not know to count the sequence. I simply thought maybe it had something to do with fuel pressure after so many failed attempts at starting. Duh.

In reading the link you just provided to one of the threads, there seems to be some debate as to whether I would even have a fault code stored in the computer after having so many successful restarts since the last failure. If there is no code stored in the computer, I'm guessing that the ckp sensor is still the likely culprit, and I'll simply replace it. Did I just say simply? Couldn't I please just go ahead and replace the side stand switch instead? It's so much easier!

 

[Woodaddict]

wasting your time and money on sidestand switch

 

[dnktng]

In reading the link you just provided to one of the threads, there seems to be some debate as to whether I would even have a fault code stored in the computer after having so many successful restarts since the last failure. If there is no code stored in the computer, I'm guessing that the ckp sensor is still the likely culprit, and I'll simply replace it.

The fault codes stored in the ECM don't get erased by conducting more starts, or time, or the condition clearing. They can be cleared by doing what is in that link. I don't even think that disconnecting the battery will clear the ECM stored codes.

 

[mikesim]

The fault codes stored in the ECM don't get erased by conducting more starts, or time, or the condition clearing. They can be cleared by doing what is in that link. I don't even think that disconnecting the battery will clear the ECM stored codes.

Previous fault codes will eventually clear themselves after numerous good self tests. The reason for the apparent failure after a heat soak is that the CKP sensor is located under the right engine side cover and is directly adjacent to the down pipes. After shut off on hot days, the down pipes can radiate a significant amount of heat to the sensor causing an open circuit. Remember, heat expands, cold contracts. As the sensor heats a winding in the sensor opens causing loss of continuity. When it cools the windings regain contact and the sensor works normally.

Mike

 

[Brillot2000]

My CX500, and cx650 turbo, would both spin the starter motor with the kill switch in the kill position, so that's why I thought the same thing would happen on this bike.

I do not currently have a MIL. I did notice that, after several attempts to start the engine, what I thought was the fuel injection lamp did start to Blink. But I did not know the significance of it, and therefore did not know to count the sequence. I simply thought maybe it had something to do with fuel pressure after so many failed attempts at starting. Duh.

In reading the link you just provided to one of the threads, there seems to be some debate as to whether I would even have a fault code stored in the computer after having so many successful restarts since the last failure. If there is no code stored in the computer, I'm guessing that the ckp sensor is still the likely culprit, and I'll simply replace it. Did I just say simply? Couldn't I please just go ahead and replace the side stand switch instead? It's so much easier!

As I mentioned to you before, this issue is intermittent and will progressively get worst in time. That's how mine worked out. Sounds like you got your first warning.

If my memory serves me, I do recall on the first time the MIL flashed for a brief moment when the failure occurred. I cycled the ignition switch a couple of times and the bike started up just fine, no MIL at that time. The last time it occurred the bike would not started using the procedure of cycling the ignition switch several times. The bike cranked, cranked and nothing until the battery was ran down. The MIL was flashing a code of a long flash followed by 9 short ones (19), CKP Fault...

I had to call AAA to tow me home. An hour later on and after charging the battery, the bike started perfectly. I decided not fool around with this anymore and decided to get the Crankshaft Position Sensor or simply Pulse Generator replaced.

 

[Brillot2000]

Previous fault codes will eventually clear themselves after numerous good self tests. The reason for the apparent failure after a heat soak is that the CKP sensor is located under the right engine side cover and is directly adjacent to the down pipes. After shut off on hot days, the down pipes can radiate a significant amount of heat to the sensor causing an open circuit. Remember, heat expands, cold contracts. As the sensor heats a winding in the sensor opens causing loss of continuity. When it cools the windings regain contact and the sensor works normally.

Mike

Your explanation is partially correct. However, the winding does not go open or infinite ohms. The heat creates a condition called "Temperature Rise" and the resistance of winding raises. The coil is supposed to have a given impedance range, for discussion for purposes lets says it's supossed to be 300 to 440 ohms. If the coil resistance is at for this example 480 ohms after soaking in the heat the ECU will be not seeing the correct voltage threshold levels from the sensor and simply ignores them. Thus creating the "No Start" connection.

Here's some light reading for those interested in knowing more about coils and temperature rise. Estimating Temperature Rise of Transformers

The Crankshaft Positioning Sensor or Pulse Generator is basically a transformer generating a signal for the the ECU.

 

[ARKNT]

However, the winding does not go open or infinite ohms

Bruce you probably have it there. I had been reading this thread and trying to come up with the root cause and it wasn't coming to me very well.
It is hard to picture a wire of the coil opening under the heat and re-closing consistently enough to function normally again for any amount of time. A loss of signal strength from the heat just enough to cause the ECU to fault and ignore is quite plausible. Also notice that the service manual checks the sensor voltage spike level, not a simple ohm check of the coil.
An ohm check would probably not be very effective here.
It would be nice if these sensors were a little less sensitive to this failure mode.

Brad

 

[Turbo DV8]

I just pulled a code from the computer. Does the number 19 ring a bell with anyone here?

I thought Honda's were supposed to be barely worn in at sixteen thousand miles, not worn out...

The irony is, I abandoned my CX turbos for long trips due to them becoming long in the tooth, and if they failed on a trip, no shop would touch them with a ten-foot pole. So I purchased this bike to avoid such problems. It's ironic that, at 16,000 miles, the crankshaft angle sensor goes out on the NT, but in almost 100,000 miles of riding CX turbos, I never had a crankshaft angle sensor go out! Other owners of that bike did, though, because when the water pump seal would begin to fail, it would immerse the cavity where the sensor is located with moisture, and cause them to fail. Or worse, people would plug the weep hole not knowing that it was there for a reason, and then their crankshaft angle sensor would fail very quickly. A good reason to not put off a repair of a leaking water pump on a CX Turbo!

The other irony of the crankshaft angle sensor failing at sixteen thousand miles on the NT, is that seems to be a magic number, because that's about the mileage at which the stators would fail on the Honda turbos! Seems to be a magic Honda number, somehow, in my experience. But I would much rather change this sensor on the NT, then a stator on the turbo. Pulling the engine out of over a half-dozen turbos cured me of ever wanting to do that again at this stage of my life.

 

[Brillot2000]

I just pulled a code from the computer. Does the number 19 ring a bell with anyone here?

I thought Honda's were supposed to be barely worn in at sixteen thousand miles, not worn out...

The irony is, I abandoned my CX turbos for long trips due to them becoming long in the tooth, and if they failed on a trip, no shop would touch them with a ten-foot pole. So I purchased this bike to avoid such problems. It's ironic that, at 16,000 miles, the crankshaft angle sensor goes out on the NT, but in almost 100,000 miles of riding CX turbos, I never had a crankshaft angle sensor go out! Other owners of that bike did, though, because when the water pump seal would begin to fail, it would immerse the cavity where the sensor is located with moisture, and cause them to fail. Or worse, people would plug the weep hole not knowing that it was there for a reason, and then their crankshaft angle sensor would fail very quickly. A good reason to not put off a repair of a leaking water pump on a CX Turbo!

The other irony of the crankshaft angle sensor failing at sixteen thousand miles on the NT, is that seems to be a magic number, because that's about the mileage at which the stators would fail on the Honda turbos! Seems to be a magic Honda number, somehow, in my experience. But I would much rather change this sensor on the NT, then a stator on the turbo.

That's the Crankshaft Positioning Sensor Fault Code. There's your problem. As I mentioned many times before this is probably your first instance and it will get only worst in time.

It is possible that a group of parts used when these bikes were built were on the high-side of the specification limits or just on the edge of the limit. This occurs from time to time in the manufacturing process. It still meets the specifications and the part is sent to the cumstomer for use.

My advice to you is to nip this in the bud and change out the sensor ASAP. I have not had any repeat instances after replacing mine.

 

[seagrass]

I just pulled a code from the computer. Does the number 19 ring a bell with anyone here?

I thought Honda's were supposed to be barely worn in at sixteen thousand miles, not worn out...

The irony is, I abandoned my CX turbos for long trips due to them becoming long in the tooth, and if they failed on a trip, no shop would touch them with a ten-foot pole. So I purchased this bike to avoid such problems. It's ironic that, at 16,000 miles, the crankshaft angle sensor goes out on the NT, but in almost 100,000 miles of riding CX turbos, I never had a crankshaft angle sensor go out! Other owners of that bike did, though, because when the water pump seal would begin to fail, it would immerse the cavity where the sensor is located with moisture, and cause them to fail. Or worse, people would plug the weep hole not knowing that it was there for a reason, and then their crankshaft angle sensor would fail very quickly. A good reason to not put off a repair of a leaking water pump on a CX Turbo!

The other irony of the crankshaft angle sensor failing at sixteen thousand miles on the NT, is that seems to be a magic number, because that's about the mileage at which the stators would fail on the Honda turbos! Seems to be a magic Honda number, somehow, in my experience. But I would much rather change this sensor on the NT, then a stator on the turbo. Pulling the engine out of over a half-dozen turbos cured me of ever wanting to do that again at this stage of my life.

Very true about the CX Turbo sensors. Having replaced them on my CX500 Turbo (that had a leaking mechanical seal) I know exactly what you are talking about. They are actually called speed sensors on the CX Turbos and effectively perform the same function.

Seagrass

 

[Warren]

Turbo DV8, Sorry about the problem you are having with your NT. My NT has been very reliable over 60,000 + miles of everyday riding for 8 years. I have never had anything fail (except a battery and two stop light bulbs) and its never thrown a code. I think many others have had the same experience. Of course like any machine nothing is 100% fail safe.

 

[Turbo DV8]

I'm going to change the spark plugs and check the valves anyway, so I will just lump all these tasks together, and have one giant Love Fest.

 

[ARKNT]

They are actually called speed sensors on the CX Turbos and effectively perform the same function.

Yes it looks like the crank sensor is used for engine speed (therefore time) and the cam sensor to tell the computer when the piston is at TDC.
The crank sensor rotor has several points on it that would send a pulse each time one passed the sensor. The more pulses the more precise it could work.
The cam sensor looks to me like it only fires a pulse when the front cylinder is at TDC and also when rear is at TDC.
Either one not working and the CPU gets lost.

Brad