Intermittent ignition problem while cranking engine during starting.

Turbo DV8

Turbo DV8

Joined
Mar 2, 2016
Messages
103
Location
Silicon Valley
Three times on two recent trips, the engine would crank, but it would not fire. Fuel injection pump spools up every time. Just not firing at all. After several attempts, the FI lamp started to flash, but I think that is just because I had attempted to start it so many times. Turning the key off and on, or kill switch off and on, would reset the FI lamp.

In the first instance, because at the beginning of my trip I had left my side stand down when I put it in gear, and it killed the engine as it should, that event just put the side stand kill switch in my head. I put the bike on the center stand, with the kickstand up, and as I was cranking the engine I slightly lowered the kickstand an inch or so, and the bike fired right up. It did this the next day one time, also, and I started it the same way, by slightly lowering the kickstand. I thought, okay, kickstand kill switch. But on the other hand, it makes no sense to me why having the kickstand up or down would kill the ignition, unless the bike were put into gear. But the bike was in neutral. So I'm not convinced it's the side stand kill switch. And yesterday on a trip into the Sierra mountains, it did it again, and the bike would not fire with the kickstand in any position. Pulling in the clutch letter a few times did nothing. Then, once again, after several attempts, it fired right up, and exhibited no further problems during the ride.

It hasn't happened enough times for me to be able to say this definitively, but the three times it happened, the bike had been ridden and warm, and then shut off for 30 to 45 minutes. Upon return from my first trip when it acted up, I removed the switch and connected an analog ohmmeter to the contacts, and slowly moved the switch through its range of motion, and I could detect absolutely no Bobble or indication of a bad switch. If there were some contaminant in the switch that was moving around and causing an intermittent connection problem, could a faulty side stand switch alone cause the bike to turn over when in neutral, but not fire?

I could get a new Switch, or bypass it all together, but I would much rather understand the problem and diagnose it before I start doing things that may be barking up the wrong tree. I thought maybe the engine kill switch, but if the switch is powering up the fuel pump, I assume it's doing the same for the ignition system. Does anybody know if the kill switch has different poles for fuel pump and ignition? And how about the ignition switch itself? Do the symptoms I describe sound like they could possibly be attributed to a flaky ignition switch? The next time it acts up, which could be quite a while since I don't often take it for day rides anymore, my next thing to do would be to wiggle the kill switch and ignition switches while it's turning over to see if it starts up then. But it seems to fire and start up eventually, on its own, after several attempts, and the two times that I slightly lowered the kickstand and it fired right up, I'm really thinking that may just have been coincidence at this point. Any thoughts?
 
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Look at the codes to see what they say but my guess would be the Crank Position Sensor because the symptoms sound the same as I experienced - fails most often on hot restart.
 
From your symptoms I too would think it is the Crank Position Sensor.

If you can read the MIL codes that should verify the problem.

Seagrass
 
have experienced same problem, after riding and warm, just won't start. no code 1 time, but finally got code came up just about 3 weeks ago. CPS error, even tho it has not failed. I also opened fuel cap, just in case of vapor lock, since its after riding and sitting in sun. so whatever triggers it, can be very sporadic
 
I also would go with the seat of the pants diagnosis of the CKP sensor, however, I would be curious to see what the battery voltage is while cranking.

Mike
 
mikesim said:
. however, I would be curious to see what the battery voltage is while cranking.

Mike
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Yes..I remember my BMW boxer had a similar problem whereby if the battery was not showing 12 volts when cranking , the ABS light would stay on..Initially I thought I had a major problem with the ABS system big $$$... A new fresh battery solved the problem..
 
Turbo DV8 said:
Three times on two recent trips, the engine would crank, but it would not fire. Fuel injection pump spools up every time. Just not firing at all. After several attempts, the FI lamp started to flash, but I think that is just because I had attempted to start it so many times. Turning the key off and on, or kill switch off and on, would reset the FI lamp.
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Some sensors fail and will not allow the engine to start, but will not give a MIL until the engine has been cranked for several seconds. The Crank Position Sensor behaves exactly like you describe when it fails.

If you had a MIL, the cause of the MIL is stored in the ECM. Read the code that is stored in ECM to determine what caused your FI/MIL. Most common is the CKP (crank position sensor) but you could have CMP (cam position sensor) failure that would give nearly identical symptoms. Read the code. Stored ECM fault codes can be read and cleared using this.
 
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It is Crankshaft Positioning Sensor or referred to as the Pulse Generator on the microfiche for sure. I experienced this issue several times and the last time required an AAA tow home. My bike also required the 24k mile service very soon and would require much of the same labor to do the job. So I decided to let me local dealer handle both of these tasks and leverage my time.

You are looking at about $150-200 of you take the bike into the dealer to replace this sensor.
 
Sounds like several here have experience to point to CPS as fitting your symptoms.
The battery voltage check Mike suggested is probably an easy, non-invasive check to do before more invasive money is spent. Has your clock and/or trip meters reset? I also noticed the last time my battery was going bad that the fuel gauge swept from normal to empty back to normal as the starter was cranked, so that may be another indication to look at for a battery/charging system issue.

Brad
 
ARKNT said:
Sounds like several here have experience to point to CPS as fitting your symptoms.
The battery voltage check Mike suggested is probably an easy, non-invasive check to do before more invasive money is spent. Has your clock and/or trip meters reset? I also noticed the last time my battery was going bad that the fuel gauge swept from normal to empty back to normal as the starter was cranked, so that may be another indication to look at for a battery/charging system issue.

Brad
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This issue starts out intermittent at first and possibly will throw a code that disappears quickly as it shows up. It could be weeks or months before it shows up again. If it does, it will be more dramatic and a code will be recorded in the ECU that can be retrieved by simply cranking the engine with the kickstand down for 10 seconds. One long flash followed by 8 short flashes is code 18 and that states Crankshaft Positioning Sensor (a.k.a. Pulse Generator).
 
Thanks, all, for the replies. Wow, not only is the consensus the CPS, but the sheer number of that consensus suggest this is a common problem with this bike? Just as an interesting musing, if it is the cam or crank position sensor , if that were to fail while the engine is running, would it kill the engine? Or if the cam or crank shaft position sensor fails while running , with the engine just run merrily along by either doubling or halving the value from the remaining cam or crank sensor?

The starter turns the engine over fast as a banshee, and when it does finally start, the battery has been dragged down after the several attempts, so I'm guessing it's not battery voltage issue. Is the yellow, flashing fuel injection light what is referred to as the MIL code? Where is the CPS located? I am just about due for an air filter, spark plug, and valve adjustment check, so would the work involved in doing those get me halfway to the CPS?
 
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Dnktng, in the process you described to read the code stored in the ECU, when you say to make sure the engine kill switch is "on," do you mean in the position which would allow you to crank the engine, or to kill the engine?
 
When the CPS cools the bike will start just fine. This problem only pokes out its "Ugly Head" after the engine is hot and the bike sets for more than 20 minutes and then when you try to leave after a quick errand.

CPS is located behind the right engine case cover. However, on the microfiche, it can be found with the Pulse Generator/Starting Clutch (Item 9). Go figure as it is not on that side of the engine.
 
Turbo DV8 said:
Dnktng, in the process you described to read the code stored in the ECU, when you say to make sure the engine kill switch is "on," do you mean in the position which would allow you to crank the engine, or to kill the engine?
Click to expand...

Use the same process when you start the bike, however, the side stand needs to be in the down position while cranking the engine. You will need to crank the engine for about 10 seconds or so for the code to be displayed using the eninge check light.
 
Here is how it looks with the right side engine cover removed. The Crank Position Sensor is at about 2 O'clock in the photo - a small black box, along the outer edge of the crankcase.

Clutch cover removed.jpg

I had to remove the muffler and the Y-pipe connector. Also the nuts for the headpipes had to be backed-off to provide wiggle room to get the clutch cover off. The nuts for the rear pipe is a real bear and it was very tedious to turn the nuts in that tight space!
 
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Thanks for the picture. Wish I could figure out how to post a picture successfully on this forum. How DID you even gain access to the acorn nuts on the rear cylinder header? From up above under the gas tank?

What area do I need to access in order to get to the connector end of the sensor?

In the service manual in the fuel injection section, it references the acronym DTC. What does this mean? Is the MIL the same thing as the orange light that looks like a fuel pump? If not, where is the MIL, and what does it look like?

To clarify my understanding, if a fault code was set, I can either use the procedure outline in the link provided in this thread, which includes involving a jumper at one of the ECU connectors. Or, I can simply turn the kill switch off, kickstand down, and crank the engine for 10 seconds, and it will then set the check engine light flashing, indicating any previous fault codes stored?
 
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I did the rear pipe acorn nuts from above and I can't remember if the tank was tipped up or not. The outside nut is OK but the inside one is a real bear so just be patient. The connector is close to the radiator so easy to access - just follow the wires coming from that place on the crankcase. I've never heard of that sensor failing while the bike is being ridden - when there is air moving over that area the sensor works fine.

After riding, heat builds-up and causes a temporarily failure. Both times it happened to me was in a gas station and after about a 15-minutes cool off, it finally restarted. I've heard of people throwing water at that area of the crankcase and speeding up the cooling process but I never tried that.

The DTC is a testing connector and the MIL are the codes. I honestly don't remember how to retrieve the codes but just follow the procedure in the service manual.
 
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Since this seems not to be an uncommon problem, I'm just curious what mileage others have experienced this at. Peaches has only 16 thousand miles on her, and this seems like a very low mileage to have a sensor failure.
 
Turbo DV8 said:
Since this seems not to be an uncommon problem, I'm just curious what mileage others have experienced this at. Peaches has only 16 thousand miles on her, and this seems like a very low mileage to have a sensor failure.
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NaTalie had about 16k on her when I picked her up last November. I do believe the instance that left me stranded had occurred at about 22k or so. That's why I had the 24k service done at the same time when the CPS was replaced.
 
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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 special test connector that you don't have.
 
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