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'06 600 Bogging at 1/4 throttle plus PAIR code

5K views 72 replies 6 participants last post by  Cherryriver 
#1 · (Edited)
'06 600 Bogging at 1/4 throttle

So another adventure along the way of attempting to resurrect this 2006 GSX-R600 the Missus grabbed off Craigslist for a very low price.
First was a blown freeze plug and water in the oil and oil in the water. I made some progress there, hoping that issue is under control.
So I rode it just now with new oil and filter installed and I now I get a serious bogging of the engine at exactly the same place in the throttle position, about 20-25% open. It's not related to revs or road speed- it's an exact point in the throttle operation where it suddenly goes "blaggghh" and stops gaining much speed.
I don't think it did that previously, although my riding is confined to a few hundred yards with the oil contamination issue, just going down the street to warm up the oil and agitate the contamination to drain it.
During all the other to-do's, it just showed a C49 code now, the PAIR valve. I have a sneaking suspicion that while dismantling things to get inside the valve cover, I pulled a wire out of the connector.
Also, the previous owner disconnected the PAIR piping, I do believe. The hose that departs the valve towards the rear of the engine simply goes nowhere. It just lays there, open on the further end.
My forum searches aren't producing quite the right set of circumstances.
If this was carburetors, I'd swear the needle and/or main jet was clogged.
(Edited to add- that wayward hose from the PAIR valve, I belatedly discovered, goes to a nipple on the underside of the airbox. Don't know if it was like that before or if I just plain missed it.)
 
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#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?
 
#29 ·
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.
 
#30 ·
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.

Text Line Font Design Parallel


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.
 
#32 · (Edited)
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.
 
#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.
 
#33 ·
@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.
Auto part Engine Automotive engine part Carburetor


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")
Auto part Gear Differential Transmission part Hardware accessory


From this picture we can tell that #1/#4 is about 45 degrees BTDC.
Auto part Automotive alternator Automotive starter motor Automotive engine part Engine


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)
Line art Auto part Circle Drawing


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.
 
#34 ·
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.
 
#35 ·
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.
 
#38 · (Edited)
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:
 
#39 ·
@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.
 
#41 · (Edited)
Here's a picture of the backside of the crankshaft sprocket that's closer to straight on and has less perspective error. As best I can tell, the middle of the crankshaft indexing tooth and the middle of the wide CKP sensor "tooth" are right at 45° apart.


There's a lot going on with that sprocket. The crankshaft splines are 20° apart (17 + 1 missing), there are 17 equally spaced camshaft chain teeth, and the CKP teeth are 15° apart (22 + 2 missing).
 
#43 ·
^John's first pic in #33 seems to show the indexing tab lined up with the #4 pin. I don't have a better pic but some crappy ones seem to show the same thing.

I'm almost afraid to bring this up but here's the previous design crankshaft sprocket. Note the apparent absence of an indexing spline as well as no wide "tooth" for the CKP sensor. So it seems to mount on the crankshaft at any of 18 positions. I'm thinking that it must rely on the CMP sensor for timing but that's just guessing. Go figure.
 
#45 · (Edited)
^That's it. The dimple is supposed to align with a corresponding dimple on the crankshaft. It's for K1/K2 1000 and some 600/750's of that era. It would seem that unless the CMP sensor is periodically checked, a missed CKP pulse would leave the spark 45° out of time. That might be a rare occurrence. The newer design appeared in K3.

P.S. Here and here is some info about Suzuki's and variable reluctance sensors for someone who wants to dig in. But I'll pass. There seem to be two major issues, 1. the shape of the signal and 2. the signal amplitude is proportional to the RPM. So some serious signal processing is needed.
 
#46 ·
Gentlemen: Allow me to once again express my appreciation for your deep dive into this topic. I'm still not sure it's educational to everyone but it's still interesting to me.
I thought I had my forum settings set to notify me of new postings, so I missed the last several posts until checking back in this evening. All fascinating stuff.
To report on my doings, against my better judgement I ordered out a set of aftermarket coils. After all, I am getting a coil failure code, even if the diagnosing process suggests it isn't the problem.
And it isn't. The new coils provided no change in behavior. Guess one set or the other will wind up on Ebay.
In the meantime I'd also done a ******* fuel pump test, not quite to the book procedure, but it pumped gas convincingly and so that seems good.
To the point of checking the crankshaft position sensor condition: initially, I just blew the scrap particles off with the air hose. Knowing I have another oil change or two coming, I wasn't too worried about where they went.
As time and this thread went on, I went back and used a cotton swab to clean it again, more carefully. Still no change, though.
I have been digging around the 'net and ran across two sort of subtle clues, including a YouTube video of a fellow with almost exactly the same issue as mine. He got nowhere according to his video, but a commenter did come in, sounding as though he was a Suzuki tech at some point, and casually tossed off that it's the camshaft position sensor failing by giving low voltage, and that it's been the subject of dealer tech updates for years. I'd like to get some further info on that. I don't have a good, longtime Suzuki dealer with a good service department immediately available around here so it will take some spare time and travel. It's not the sort of thing to be done on the phone, it's a face-to-face thing.
I do recall running across a vaguely similar thread somewhere where someone else found the CMP sensor at fault as well.
I decided to grasp at that straw and order out a new OEM CMP sensor, for $122 shipped and taxed.
I am close to pulling the clutch cover and having a look around inside. I wish I'd thought to order a new gasket, even though I've pulled other clutch covers and re-used the original gasket just fine. Indeed, the Missus' other Suzuki, and '04 SV650S, went through that when she insisted upon my installing a Rekluse auto-clutch the same as the one in her preceeding Ninja 650. (A whole other story.)
I expect the CMP sensor by around the end of the week and I will report back. During that time, I will be studying these ignition system nuances and increasing my knowledge of modern computer-controlled motorcycles.
 
#47 · (Edited)
Thanks for putting up with our posts. Though we're diverging somewhat, I hope it's apparent that what's driving it all is your problem. We're focusing on the CKP sensor right now but no one knows for sure.

I see that the CKP sensor was changed for K6 600. But it looks like the previous sensor, just repositioned. They also switched the CMP sensor to a Hall effect type (three wires instead of two is the giveaway). I'm unaware of any issues with it and a search for things like "gsxr camshaft position sensor tsb" didn't find anything. Used CKP sensors are as cheap as $15 on ebay and used CMP sensors for less than $30 but suit yourself.

I've never understood why Suzuki switched from variable reluctance to Hall effect for one sensor and not both. At redline the CKP sensor is putting out somewhere around 5200 pulses/sec vs 110 for the CMP. That may have something to do with it. Alternately, at idle the CKP sensor generates around 600 pulses/sec vs 12.5 for the CMP. The signal produced by a variable reluctance sensor varies with speed so the Hall effect may have an advantage at low speeds.
 
#48 ·
Trying to do things in a semblance of order, maybe I got behind.
So I picked a CM
KP sensor off Ebay, about forty bucks. I'll replace the one sensor first, try it, and then the other, to see if there's a clear indication.
A little more info. I've done my test riding up and down an unoccupied street. I tried simply running it in the garage on the lift. Key indication: if I try to hold say, 8000rpm steadily, it cuts in and out noticeably cleanly. Revs jump a thousand or two as the one pair seems to cut in and out. The cycle is a second or two, not long but not a blink, either.
Interestingly, the headlight seems to flicker very slightly brighter and dimmer in concert. New battery.
 
#50 ·
A little more info. I've done my test riding up and down an unoccupied street. I tried simply running it in the garage on the lift. Key indication: if I try to hold say, 8000rpm steadily, it cuts in and out noticeably cleanly. Revs jump a thousand or two as the one pair seems to cut in and out. The cycle is a second or two, not long but not a blink, either.
Interestingly, the headlight seems to flicker very slightly brighter and dimmer in concert. New battery.
Now that is interesting. If you check the wiring diagram, the ignition switch is pretty much the only component common to the headlight and ECM power. (As long as your battery and other power connections are sound)

I wonder if at a certain vibration frequency the ignition switch contacts start interrupting power to the ECM causing it to glitch?

The check would be to temporarily jump power past the switch and see if the problem resolves.
 
#54 ·
billv, that's getting to be quite a bit of thinking.
Hoping to get the show on the road and actually ride the thing in real life to see what else might be amiss, but I'll see if those items can get a look. I agree it's a thing.
I did sort of give the kill switch a thought after poring over the wiring diagram the other day. I've had Hondas including three Wings, and while they were superbly-made machines they had a weakness in switches: one 18 ate a front brake light switch every few years and a couple others. A kill switch is relatively in the open if the bike was stored outside and does have grounds for being suspected. (Not necessarily a pun.)
 
#55 ·
If there is a connection between your lights changing brightness and the ECM fault it would not be the kill switch, side stand switch or relay. They have no effect on the headlight circuit. This is why I mentioned the ignition switch.
 
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