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Discussion Starter #21
Spyder, I'm pretty sure what you say is true.
What makes me sort of consider injector clogging is that it's staying with the same two cylinders, 1 and 4 even when I flipped the coils around. And, the misfiring is throttle-position related, as if, just speculating here, the secondary injectors are not contributing. But that's just guessing.
But then, on a lot of bikes that pair fires together, and I would have to take a deeper dive into the GSXR600 book to know if that's the case with this bike. If so, then it could be reasonable to expect something in the spark-triggering. Except, the manual says that the coils are getting the fire signal.
I'm getting a little more inclined to get a set of coils, but I don't really want to get into the parts-changing diagnosis thing if I can help it.
The fact that this exact thing has afflicted others here and they went way down the rabbit hole chasing it is making me hold short. So far, in my searching the forum, the only successful resolution came from a guy who changed out his coils, I think.
Also, I took a look inside the fuel tank with a good light and didn't see anything particularly frightening, including the exterior of the fuel pump. That's not to say there isn't clogging in the filters, but without a lot of junk showing, it makes me want to think the filters are okay.
Plus, again: the code is for ignition.
One thing about going around in a circle is that you get familiar with where you're lost.
 

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"I notice that the faults reported are the cylinder pairs that (I believe) fire together, 1+4 and 2+3." and "bikes that pair fires together"

AFAIK the pistons go up and down together but they fire on successive strokes. Otherwise it would sound like a two cylinder. The K1 1000 service manual had a nice Injection Timing diagram showing all that but it has since been omitted.

$160 does sound like a lot. That's $10/O-ring. Maybe I'm a cheap-ass but I'd be thinking in terms of $2/O-ring. The quality may vary but there's lots of sellers. Just pay attention to getting the correct size.
 

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Discussion Starter #23
Well, on a lot of four-cylinders in my past experience, they often fire a "waste" spark on the exhaust stroke just because it's easier to set up the triggers that way. I was guessing that might be the case here, but poring through the manual, perhaps not. The ECU has separate outputs for each cylinder. I imagine the crank trigger hits each revolution, though.
The o-rings indeed are about $7 and $9, plus tax. Partzilla's price is pretty close to that, too. Yeah, it's a lot.
 

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Have you checked the pins and connectors on the ECM? Corrosion? Or sometimes the male portion gets pushed back in the connector making a poor connection.

The ECM in your bike is not that sophisticated. It does not detect misfires so I don't believe it is a fuel issue.

It also does not work in "pairs" as far as I know. I had a bad coil on one of my bikes and it just reported the error on one coil.
 

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Discussion Starter #25
The ECM connections appeared to be in good order. I have yet to find anywhere on this bike a corroded connection. Typically, if you've got one you've got several, but those parts seem clean.
I replaced the spark plugs. The ones in there actually looked quite good for their age; they seem to be a good 5K miles old at the least, but the color was nice and there was no fouling and little electrode deterioration if any. But, new ones in there now.
Fired it up, and sure enough, whack the throttle and I get C24-27.
Having just also put on some new Pirelli Diablo Corso IIIs and a new battery, along with lots of oil and sundries, I'm denting the available budget. Not quite wrecked it yet, so maybe I can extract enough for new coils. Since, after all, the thing thinks there's a coil problem.
So now torn between the aftermarket one at a buck and a quarter or Ebay-ed used stockers. Going four hundred for new OEMs is a bit tough.
Possibly not relevant, but I also have a ZRX and the ZRX forum is wonderful beyond belief. I have noted threads over time where the poster converted his Rex to stick coils and then went back since the stick coils were not as reliable. I'm not saying that has a lot of bearing here, but it does come to mind.
This GSXR shows about 22,000 miles (and no crash evidence!)
 

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You can get injector O-rings as long as you have a good one to measure. I know I've had luck looking for them in the Hydraulic section before. You just match up the size in mm and it's the same. get them for anywhere from 30 cents to couple dollars. Any good hydraulic supply should have them.
 

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If you've swapped the #1 for the #2 and the #3 for the #4 coils and still see the same error, it tends to say that the coils are OK. I'm still thinking in terms of power to the coils.

I don't have the K6 600 wiring diagram but it ought to be similar to the K6 1000 diagram, which I do. We've talked earlier about a distribution block for the Gr leads to the coils. It's supplied by an O/W lead that comes from the engine stop switch and also supplies the PAIR solenoid, ECM, dealer mode connector, fuel pump relay, and fan relay. With that many splits, there's likely to be another distribution block for the O/W leads. You could try looking for it and making sure that it is also OK. Unfortunately I don't have any idea where it is. Also I don't see why a problem with it would only effect the #1 and #4 coils.
 

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Discussion Starter #28
billv, I'm going back in there with that in mind, and with a meter. And all the persnickety patience I can muster.
I think I also need to have a look at the wire terminations in the plug caps, as if they might have been pulled loose during coil removal.
The fact that others seem to have been afflicted by the same pair type of failure still sticks. I believe I've seen three other threads where the outside pair or the inside pair gave trouble, with 1-4 being the more common. I keep getting the feeling there's a clue there and I'm missing it.
The rest of the bike has come along pretty well. Now, wouldn't be great if I could get the engine running halfway right?
 

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I think it's going to be the crank or cam sensor. The cam sensor is really only useful to tell the ECM if cylinder 1 is TDC on compression stroke or TDC on exhaust. After that, it's every other revolution. Based on other manuals, the signal that the ECM uses for fuel/ignition timing is the crank sensor. But what happens if it's 10 pulses on the crank sensor for every one on the cam, and a failure on one or the other is mucking up that ratio? At this point, replace the cheaper one and hope it fixes it.
 

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I'm pretty sure that the CMP sensor is only used at starting and disregarded once the engine is running. Once it knows cylinder #1 is on TDC compression stroke, it can keep track with just the CKP sensor after that.

This is borne out by the Fail Safe chart in the service manual.

Clipboard01.jpg

I first became aware of this when working on my Aprilia SXV. It is a V-twin with only a CKP sensor. The ECM throws spark at both cylinders for about 20 seconds and then figures out which cylinder to fire by the pulse intervals. A not uncommon mistake on those engines would be to install the cams 180 degrees off. It would start just fine and run for 20 seconds :wink

I just don't see how a faulty CKP could produce these codes on those two cylinders so consistently. Even the manual's possible "things to check" does not mention the CKP as a possible culprit.
"Ignition coil, wiring/coupler connection, power supply from the battery"

I know it has been checked, but my guess would be the that there is a poor connection on the O/W power wires to those two cylinders. At a certain rpm, it might just vibrate the poor connection enough to trigger the fault.
 

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Discussion Starter #31
Well, I certainly hope this is educational in some way to somebody somewhere. I know I'm nearing the end of my patience, and that's from a guy who rode everywhere on a BSA twin for years, and owned a Velocette Thruxton for a while, too. Cheater that I am, I adapted a Mikuni (in the very early '70s) to it so that it had some semblance of an idle, but that's a story for another day.
I dug in there and did continuity checks on all eight spark wires, the hot side to the sockets on the ECM connectors and the grounds to the gang-ground there. Everything was fine. I did not check actual resistance. Possibly an error.
I got momentarily excited to discover a broken wire just in front of the ECM's black connector, and thought it was the camshaft position sensor wire. Yeah, no, not if you look at the ECM pin numbers in the correct direction. It's the EXCVA wire apparently, and it seems it had been cut to avoid the C46 error- which I immediately got when I put in a jumper splice (soldered and shrink-wrapped!) and turned the key.
I guess I'll take one more good look at the coil connections, even though I believe I'd done so already, and then I guess pop for coils. Again, the only forum thread I could find where a guy claimed success with the 1-4 or 2-3 code was when he put in new coils.
I do appreciate the tutoring. I am learning about GSXRs, even though I may not own one much longer at this rate.
 

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I'm pretty sure that the CMP sensor is only used at starting and disregarded once the engine is running. Once it knows cylinder #1 is on TDC compression stroke, it can keep track with just the CKP sensor after that.

This is borne out by the Fail Safe chart in the service manual.

View attachment 288223

I first became aware of this when working on my Aprilia SXV. It is a V-twin with only a CKP sensor. The ECM throws spark at both cylinders for about 20 seconds and then figures out which cylinder to fire by the pulse intervals. A not uncommon mistake on those engines would be to install the cams 180 degrees off. It would start just fine and run for 20 seconds :wink

I just don't see how a faulty CKP could produce these codes on those two cylinders so consistently. Even the manual's possible "things to check" does not mention the CKP as a possible culprit.
"Ignition coil, wiring/coupler connection, power supply from the battery"

I know it has been checked, but my guess would be the that there is a poor connection on the O/W power wires to those two cylinders. At a certain rpm, it might just vibrate the poor connection enough to trigger the fault.
I'm right there with you. The crank sensor picks up off the cam chain drive sprocket. If you look at a picture, it's got a "tall" spot in it that the ECM can use to stay honest. The cam sensor just tells it which cycle it's on. Once it knows that, it's binary and it really doesn't need the cam sensor at all. Crank sensor isn't cheap and it's a bit of work to change out. Have to drain the oil, get a gasket for the timing inspection cover and starter clutch cap. Remove the starter clutch cap, clutch, and idler, and then the cover. It's about a $200 job just in parts.

But, if this were my bike, I'd be ordering the parts.

Just thinking about it a bit more. The pairs are out of phase. Call #1 and #4 at the top of the rotation, and #2 and #3 at the bottom. It just fires one of the pair every other rotation. So if the sensor was picking up a problem in the first half of the rotation, it might error on #2 and #3. If it was picking up a problem in the second half, it would be #1 and #4. Maybe not explaining that right, but it sort of makes sense to me.
 

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@Chuckster. I understand what you are saying about the pairing of cylinders as #1 and #4 are in the same position whereas #2 and #3 are both 180 degrees out.

When I helped out a guy with a K7 600 that would not start about a month ago, I remember thinking the CKP was not in the position I expected it to be when we pulled the cover off.

As you can see from the picture below, the "wide" tooth on the cam chain side of the engine is clearly lined up with the #1 and #4 crank pins.
1 GSXR K6 600 crankshaft large notch to cyl 1 and 4.jpg

On installation of the cam chain sprocket/trigger wheel, the "wide" tooth is aligned with the wide trigger portion of the trigger wheel. Otherwise, when cylinder #1 is TDC, the wide trigger is pointing towards TDC. ("up")
2 GSXR K6 600 Cam chain sprocket installation wide tooth.jpg

From this picture we can tell that #1/#4 is about 45 degrees BTDC.
3 GSXR K6 600 trigger wheel installed..jpg

The kicker is that the CKP is mounted below the trigger wheel so it would be giving it's long "high" pulse at BTC of cylinders #1 and #4 or TDC of #2 and #3. (I flipped the following cover picture to orient it with the engine picture)
4 GSXR K6 600 CKP location in cover.jpg

Of course this does not help the OP directly, but it is interesting just when the CKP receives the long signal on each crankshaft rotation. It seems that #2 and #3 get direct pulses for timing and timing for #1 and #4 is interpreted.
 

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If I'm understanding those pics correctly, and the wide spline lines up with #1 TDC then the wide part wouldn't be over the sensor when any of the four were at TDC.

All of it could be interpreted too. The frequency could be used to calculate a delay and the processor clock in the ECM is doing the work. This starts a new hypothesis. The wide part is not as tall as the other points. This suggests the CKP is a variable proximity switch and brings new meaning to the peak voltage check. That half height could be telling the ECM that it's still getting signal from the sensor, but it's neither a high nor a low. So let's assume a failing sensor is dropping voltage. What would the ECM think is happening? Would it basically be seeing two half height segments? If the first part of the theory is correct, the clock would be resetting and skipping an ignition cycle. The other thread in ECM would see the missed cycle for the pair. But the ECM would still be getting signal from the CKP and not throw a code for it. I just think that would be too erratic to stay consistent on a specific pair.

It's just fun to try and understand what's going on with the logic.
 

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If I'm understanding those pics correctly, and the wide spline lines up with #1 TDC then the wide part wouldn't be over the sensor when any of the four were at TDC.

All of it could be interpreted too. The frequency could be used to calculate a delay and the processor clock in the ECM is doing the work. This starts a new hypothesis. The wide part is not as tall as the other points. This suggests the CKP is a variable proximity switch and brings new meaning to the peak voltage check. That half height could be telling the ECM that it's still getting signal from the sensor, but it's neither a high nor a low. So let's assume a failing sensor is dropping voltage. What would the ECM think is happening? Would it basically be seeing two half height segments? If the first part of the theory is correct, the clock would be resetting and skipping an ignition cycle. The other thread in ECM would see the missed cycle for the pair. But the ECM would still be getting signal from the CKP and not throw a code for it. I just think that would be too erratic to stay consistent on a specific pair.

It's just fun to try and understand what's going on with the logic.
The crank pins for cylinders #2 and #3 are 180 off so the wide part of the trigger would be over the sensor when they were TDC. You are right that it is really not important where the sensor is. After one rotation, the ECM knows where the crank is and can interpret everything else from there.

Good question as to whether the slightly lower profile of the wide part of the trigger wheel is significant.
From what I've read about car systems, the CKP actually sees a voltage peak from each tooth with the wide tooth being the reference point. This is how cars can determine a misfire on a particular cylinder as it sees the crankshaft speed drop during that misfire. Pretty clever but I don't think the gsxr ECMs monitor this.

As a guess, I'm down to the CKP as you suggest or possibly the ECM itself.
 

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Maybe terminology? Connecting rod big end journal?

Crankshaft pic with labels.jpg

Crankshaft pic 2.jpg
 

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I think that the CKP sensor is a variable reluctance type, basically a magnet with a wire coil around it.

"Good question as to whether the slightly lower profile of the wide part of the trigger wheel is significant."
Don't know for sure but thought that the low/wide part is a midpoint between the top and bottom of the tooth profile.

The OP mentioned earlier that he'd checked the sensor, though not with a peak voltage sensor. I'm grasping but am wondering if he didn't look closely enough and that there might still be stuff on either the sensor or the sprocket. Given the problems that he's having, I'd think it appropriate to check things while rotating the crankshaft a full revolution.

P.S. Here's a pic showing the relative orientation of the wide CKP sensor "tooth" and the indexing tooth for the crankshaft:


and here's the whole works:
 

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@billv Those are better pics of the relationship between the wide tooth on the crank and wide trigger section on the wheel. It's interesting that the wide area leads TDC by about 45 degrees.

I believe the sensor is as you described. When I took the cover off on the non-running bike, one of the mounting screws was loose and "stuck" to the sensor.

As I mentioned before, even with the screw stuck to the sensor, the peak voltage check was in spec :|

The bike did not produce spark and there were no fault codes.

We didn't find the problem till we removed the cover.
 
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