[yasir.ghiasi]

Hi all, I am getting quite desperate in my troubleshooting, and I would really appreciate if any of you in here could help or have had the same problem. This is my first post here, so please be gentle.

Short version: My TL1000R won't fire the rear cylinder, so far I have changed the coils, spark plugs and intermediate wires from the ecu to the coils. Still no spark. Rear coil had a crack in it, and was not reading the right ohms. Down to crankshaft position sensor, but I am now very confused.

Long version:
Bike started misfiring and then not firing at all on the rear cylinder. I checked the wiring; and the signal wire from the ecu to the coil was corroded and breaking. Fixed it. Still no spark on the rear (checked a spark plug grounded to the frame). The bike was still only running on the front cylinder. Changed the spark plug, same result.

Then I checked the coil, and found that it's most likely dead too (don't know if intermittent signal caused this), so I changed that. THEN the bike ran for all 10-20 seconds, before the rear cylinder stopped firing again.
And I keep getting the C25 error code
"Ignition coil, wiring/coupler connection, power supply from the battery." or
"CKP sensor (pick-up coil) signal is produced but signal from ignition coil is not produced continuous two times. In this case, the code c24 (for front cylinder) is indicated. c25 is indicated if rear cylinder fails." from wotid: http://wotid.com/tls/content/view/16/49/)

I have even gone so far, and changed the ECU (maybe a faulty ECU didn't make the signal) to a used one from a working bike, still no spark.

I have tested the new coil with the circuit for the front cylinder, and it works fine.

So far, it seems like the crankshaft position sensor works, since the front cylinder fires fine, and the sensor gets a signal from the pickup for the rear cylinder, but somehow the brand new ignition coils doesn't produce the signal continuously, which doesn't make any sense to me.

Does my bike just keep cursing coils? I don't know what's left to check, maybe the CKP sensor itself or the pickup.

I am at my wit's end, and would appreciate any help.

 

[Six5]

Welcome to the Zone, Yasir!

You have quite the stubborn problem there. 🤔 Thanks for the good description of what you've done so far. 👍
One other thing I would try, and maybe you already have, but it wasn't mentioned specifically.
Verify that the rear cylinder coil has a reliable connection to +12v at the orange/white wire. No corrosion. No loose terminal. No intermittent connection. It should power up with the key on. Actually, both coils are supplied with one wire, but it splits into two in order to reach both coils. Verify those connections are solid and reliable.

The tests you have done so far, seem to indicate the new coil and ECM are functional.
In fact, the ECM can only detect an ignition coil error if it doesn't see the feedback from the coil. In other words, the power supply to the coil and the control lines from the ECM need to be intact. Otherwise, an error will be generated. If you can verify those connections, and the problem still exists, the next step is the CKP sensor.

While I don't have much experience with the crankshaft sensor personally, I have read from other accomplished mechanics that the sensor can begin to fail and it may not be detectable with a meter, and it may not generate a CKP error code. So then, the only Surefire test is to replace it. As you may know, the CKP sensor is included as an assembly with the complete stator. In that case, swapping out the stator assembly is preferred over trying to separate the sensor from the stator.

Let us know what you find please.

 

[yasir.ghiasi]

Hi Six, thank you for taking the time to answer, these bikes take up a lot of time in our lives, I am just glad you are willing to help.

I have actually verified that the rear cylinder coil has a reliable connection to +12v at the orange/white wire, with just the ignition on. But I will double check, since I have left the bike alone for over 6months... This problem defeated me last year in April ... At this point it weirdly seems like the coil doesn't work with the signal voltage or the ECU doesn't generate it somehow (unlikely since it's a new used ecu). My new wire setup from the ECU can be questionable/wonky as I have just used some spare wire in the same thickness as the oem. But I have checked for continuity and resistance (just under 1ohm...?)

Can you elaborate on the sensor failing without detectability? It has been confusing me a lot, since the bike fires on the front cylinder without major issues... (i guess it can be just the the pickup magnet for the rear)

Best regards,
Yasir

 

[Six5]

.....
Can you elaborate on the sensor failing without detectability? It has been confusing me a lot, since the bike fires on the front cylinder without major issues... (i guess it can be just the the pickup magnet for the rear)
....

Unfortunately, Yasir, I can't elaborate on the CKP sensor. I have only read about such a condition where it may be faulty but undetectable with the typical testing methods. I have not personally encountered such a failure....yet.

Still, the consistent display of the c25 error code and the corresponding failure of the rear cylinder coil leads me to suspect that a problem actually does exist in coil circuit rather than the CKP sensor. I realize you have already swapped the components that make up that circuit, i.e. ECM, coil & HT wire, cap, and spark plug, and you have even jumpered the coil control line from the ECM to the ignition coil. BTW, the resistance of this wire should be very low. Less than 1 Ohm is good.

If it were mine, at this point, I would rather use a scope to take some measurements before I swap the CKP sensor, because replacing the stator and sensor is a lot of work, and it may be to no avail, given what you have discovered so far.

IMO, if you are confident that the replacement coil you installed is fully functional, then you should take a closer look at the actual control circuits. The c24 & c25 errors codes are generated by the ECM because, as the manual says, the ECM processes at least two continuous pulse events from the CKP sensor, but it gets no feedback from the ignition coil. When this happens, it generates the appropriate ignition coil error code.

The ECM can only "see feedback" from the coils by detecting the current flowing through them.
If the current is missing, then a connector or wire is likely open, or the coil itself has failed.
It the current is merely low, then there may be a resistance in the circuit, such as a corroded connector.
In either case a scope can help you see where the problem is occurring. It could allow you to look at both control lines (front and rear) to verify the duration and amplitude of the pulse. Both front and rear pulses should look nearly the same. A scope could also let you see the CKP pulse to verify that it is indeed occurring and shaped appropriately.

I'm looking forward to hear what you find.

 

[yasir.ghiasi]

Update: almost a year of problems fixed in one afternoon, although it took many days of attempts 😂 It was the most silly and basic wiring issue. The Black and yellow that had broken was NOT going to the ignition (this wire breaking coincided with the time the bike was not running of the rear cylinder), I had “fixed” this and rewired the new rear coil completely wrong. And when you throw in all the parts i replaced it was easy for me to make this blunder. It was a defective coil all along and I had been an idiot and wired it wrong to the ECU. It took a simple correct check of continuity 😅😭 Thank you for your help and suggestions, it really gave me the motivation I needed, since I have been dreading my bike and left it alone for over 6 months now. Since my last attempts. After Reading up on your suggestions, i questioned everything that I had done so far, thanks again. And I Got away with not replacing the stator assembly, phew. The c25 is gone hehe. I will report back if it appears. Now on to a lot of periodic maintenance. Thanks again! 🫡😊

 

[yasir.ghiasi]

Hi All, the C25 error is back, when running the bike at high rpm, the error comes back on. I am 100% sure that the wires from the ecu to the coils are good and the signal is being produced. But the error still comes on from time to time, would upgrading the grounding to the coil help? I have no idea where the grounds on the bike are... Please feel free to help me along the way here.

 

[Six5]

Hi All, the C25 error is back, when running the bike at high rpm, the error comes back on. I am 100% sure that the wires from the ecu to the coils are good and the signal is being produced. But the error still comes on from time to time, would upgrading the grounding to the coil help? I have no idea where the grounds on the bike are... Please feel free to help me along the way here.

Yasir, Aside from the c25 code being generated sporadically, how does the engine perform at the higher RPMs?

There are no ground connections on the ignition coils themselves. True, the iron core is bolted to the frame, but it does not provide an electrical current path for the circuit. The only "ground" in that high voltage ignition circuit is the grounded spark plug electrode where the spark occurs.

However, given the nature of this failure, two possible problems come to mind.
1) Maybe the conductor you repaired that provides the trigger pulse from the ECM to the coil is failing again, or maybe at a different location than what you repaired.
2) The Main Loom Ground connection is failing. This is a common problem with the TL loom. When it begins to fail, it happens in an intermittent fashion and can cause any number odd behaviors from the instruments to ignition anomalies. The main Loom Ground connection is handled by a single spade connector on a Black/wht, 14 AWG wire that runs in parallel to the negative battery cable. That spade connector, and/or the ring terminal on the same wire that bolts to the engine case, can begin to corrode and cause problems with the electrical system. Have a look at those two items before you dive too deep into troubleshooting other stuff.

The increased vibration at higher RPMs may be causing one of these circuits to fail just enough to cause the code to come up.

 

[yasir.ghiasi]

Six5, thanks again for taking time out of your day to write such a well structured and informed reply, really appreciate it

- The engine actually performs quite nice at higher rpms, the throttle response feels quite hogged if I yank the throttle all the way (even in the right gear), but I am suspecting that this is due the TRE mod not done, ignition feels very retarded, correct me if I am wrong. I will try to do the TRE mod along with the grounding mod once I have fixed my c25 issue with the current setup.

I tested my coil recently and it seems very fine, reads exactly the same over the spades for each wire as the front one.

I am really interested in what you mentioned about the main loom ground, can you please show where the spade cable from the - of the battery connects to on the loom and where it is grounded on the engine, i suspect both locations to be pretty gunked up!

Best regards,
Yasir

 

[Six5]

......
I am really interested in what you mentioned about the main loom ground, can you please show where the spade cable from the - of the battery connects to on the loom and where it is grounded on the engine, i suspect both locations to be pretty gunked up!
.....

Yasir,
The single spade connector in the Main Loom Ground is shown in this photo. It is not a great photo, but I think you will get the idea. It is the larger (14 AWG) BLACK/White wire tucked behind the other loom wires against the frame (circled in red).

[url=https://www.flickr.com/gp/[email protected]/Trw1GV3JJ3]DSCN6002[/url] by [url=https://www.flickr.com/photos/[email protected]/]Tony Six5[/url], on Flickr

This Black/white wire eventually parallels the Negative battery cable. At some point it is crimped to the cable, and they both end in a single ring terminal that bolts to the engine case just above the front sprocket.

The other end of this Blk/wht wire is obviously connected to the network of smaller gage ground wires that run throughout the loom.

The following photos should help you identify the general components.

This is the OEM connection of the Negative battery cable to the engine case just above the front sprocket.
[url=https://www.flickr.com/gp/[email protected]/21un7u1mr1]IMG_20121103_162156[/url] by [url=https://www.flickr.com/photos/[email protected]/]Tony Six5[/url], on Flickr

This is the corrosion I encountered on the cable to case connection. It may not have been a showstopper, but it is not good either - a problem waiting to cause havoc.
[url=https://www.flickr.com/gp/[email protected]/526h8w89DY]DSCN9740[/url] by [url=https://www.flickr.com/photos/[email protected]/]Tony Six5[/url], on Flickr


This is the soldered ring terminal on the new 12 AWG Main Ground Wire I used for my repair.
[url=https://www.flickr.com/gp/[email protected]/Jnf6627h4u]DSCN9742[/url] by [url=https://www.flickr.com/photos/[email protected]/]Tony Six5[/url], on Flickr


Finally, the new ground connections to the engine case. Cleaned and coated with Noalox to slow development of future corrosion.
[url=https://www.flickr.com/gp/[email protected]/27965Qr8J2]DSCN9745[/url] by [url=https://www.flickr.com/photos/[email protected]/]Tony Six5[/url], on Flickr


I also completely removed the single spade connector and soldered the new 12AWG wire to the ground network in the Main Loom Harness, because that connector is the component that often causes the REAL problems by developing corrosion - and there is no practical need for it in the circuit. I just can't find the photos of that fix at the moment. They are here somewhere.....

This mod is not a "cure all," but it is a fix that needs to be done on many TLs, especially bikes that live in humid climates. The electrical problems it can cause are often intermittent in nature, and a lot of time, effort, and worry can be wasted in chasing such gremlins. I decided to fix it at the source. With a few tweaks to the OEM system (like this one), both of my TLs have been very reliable machines.

 

[yasir.ghiasi]

Six5, thanks for the very thourough explanation (I really needed it), I will have another crack at the bike, hopefully I can get all these things done, similar to your setup. I noticed that the smaller wire on the "-" of the battery (not the thickest one that goes directly on the terminal) on my bike ends up all the way at the regulator and from the regulator, it grounds to somewhere else (most likely the single spade connector). I cleaned the connections to the regulator and the bike fired right up (easiest cold start I have done on it). But I see now that I have more grounds to chase down. Thanks again, it's great to get an explanation from someone who had the same problems Hopefully, I can give a happy update soon

Best regards,
Yasir