07 Busa With Rough Idle And Hanging Revs

[David Offor]

I didn't know about your gear position issue or had forgotten.
There is a gear position sensor, with all my problems, I tried changing mine but it made no difference for me, I guess this could be linked to your problems but I just don't know enough about it, hopefully someone else can chime in.
Eliminate your pump and injectors first and then maybe start a new thread, with the updates, it will make identifying the fault easier, I'm now on my 6th thread .

 

[Shaun Ketterman]

I didn't know about your gear position issue or had forgotten.
There is a gear position sensor, with all my problems, I tried changing mine but it made no difference for me, I guess this could be linked to your problems but I just don't know enough about it, hopefully someone else can chime in.
Eliminate your pump and injectors first and then maybe start a new thread, with the updates, it will make identifying the fault easier, I'm now on my 6th thread .

Yeah good call. I'm going to start another thread specifically for that hanging rev issue, see what I can dig up from the knowledge base here.

Also, TPS and all 4 injectors tested good for output voltage, so I can eliminate that at least. Still waiting on this injector kit thing to come in...

 

[David Offor]

I've been told that the injector solenoids can play up, have you performed a leak test on them, just asking because there were tests I'd done in the past, only to find out later that I'd missed a specific test.
I'm still waiting on my replacement set of injectors, hope to post something positive soon.

 

[Shaun Ketterman]

Got all the injectors tested and a new pump and filter assy installed.

I'll start with the bad news...

Neither issue has been resolved. The bike STILL jerks/hesitates badly in the upper RPMs, and the idle is STILL rough. I will say that the idle seems to get worse as the bike warms up. When the engine is relatively cold, the idle is smoother, especially with the gear in actual nuetral. With the bike in gear and the clutch pulled in, the idle is much smoother, so it seems to affect neutral itself more than any gear with the clutch pulled in.

A few photos that I wanted to share:

1. My old pump was absolutely filthy:

The 'shiny' black part is where I ran a wet wipe over to show the difference. When I reassembled everything, I cleaned off all of the electrical connections as best I could. I should have taken an 'after' shot, but it looked exponentially better. I just coulnd't believe how dirty this thing was. I mean, INSIDE the tank shouldn't be this dirty, right? I used a flashlight and shone into the hole where the pump goes, as well as in the hole where the fuel cap goes. Everything I could see appeared to be clean, so this was bizarre.


2. Check out the gas that came out of the old pump and cartridge. It was friggin' BLACK:

I couldn't believe my eyes when I saw this. For those who have done this procedure before, is this normal? I can't imagine it is. Regardless, I got all of the old crap out of there and flooded the cartridge with TB cleaner until everything that poured out was clear. All the gas I pulled out of the tank prior to doing this was crystal clear though, so it must have been something in either the old pump or the cartridge. Also....I didn't take a photo, but the mesh screen filter on the pump assy was pretty clogged too, so that was replaced with a brand new one.


Finally, I was able to pull all the injectors and test them. Each has a good spray pattern, and there was zero signs of leaking or clogging. I ran each one through this motion pro cleaner I bought for 10 seconds or so.


So after a good cleaning of the injectors, new fuel pump and fuel filter, still getting the exact same indications. Rough idle and severe hesitation in the upper RPM range. Oh and the hanging rev issue is still here as well.

The good news? Well the bike feels like a whole different beast. Throttle response is AMAZING. I mean AMAZING. I damn near lost control a handful of times while casually riding around town because the slightest increase in throttle commands big time 'oomph' now, and this is all low RPMs. So that is good news. Also, the power delivery feels MUCH smoother. It was smooth before (compared to the ZX6R I had previously), but now it's even better. So maybe the injectors had some slight clogging, and changing out the fuel mesh filter helped as well.

So now as far as troubleshooting the issues, I mean, at this point it would have to be either a sensor, or something electrical? I'm going to check the TPS again sometime this week to see if the work I did + the valve adjustment threw it off. If it turns out to be good, I may just replace it to see if that helps. Other than that, I mean, could it be the plugs? They are new, and the gap is good. Or maybe the coils?


Shaun

 

[David Offor]

That's great news about the power increase on the bike but shame it hasn't sorted out the other problems. That pump must've been shot, it might explain the black liquid the early tanks used to rust out badly, clogging everything in the fuel system.
One of the guys on here (can't remember his name) mentioned the cam shaft sensor, on top of the cam cover, if faulty, can give a faulty signal to the ECU.

 

[Shaun Ketterman]

...One of the guys on here (can't remember his name) mentioned the cam shaft sensor, on top of the cam cover, if faulty, can give a faulty signal to the ECU.

When a sensor is failing will it throw a code? I just went back into dealer mode to adjust the TPS (it was off again), and the bike isnt throwing a single code.

I have a DVA adapter on the way. This allows me to test "peak voltage" which is a test that multiple sensors require. I can also test the coils this way. The cam position sensor is one such item that requires the adapter.

 

[David Offor]

Think I might get one of those.
If it's totally failed, it should throw up a code but failing, might not.
We are both playing the elimination game, I'm afraid but progress is being made.

Have you tried a different gear position switch?
Have you ruled out the clutch switch?
Have you eliminated the side stand switch? ( I hear these can cause odd problems).
Have you made sure that you don't have a tre fitted?

Look forward to seeing your 'peak voltage' findings.

 

[Shaun Ketterman]

Think I might get one of those.
If it's totally failed, it should throw up a code but failing, might not.
We are both playing the elimination game, I'm afraid but progress is being made.

Have you tried a different gear position switch?
Have you ruled out the clutch switch?
Have you eliminated the side stand switch? ( I hear these can cause odd problems).
Have you made sure that you don't have a tre fitted?

Look forward to seeing your 'peak voltage' findings.

Thanks David, that is what I was thinking. So a sensor could be going out, and causing havoc, but it won't actually throw a code until the ECM stops receiving a signal from it. Well, I've been riding around in dealer mode since yesterday morning, and even when I experience the misfire there is no code. From what I can tell, the coils don't even have a code that applies to them, so even if one is shot, I wouldn't know it.

As for all the switches you've mentioned, the short answer is no to each one.

I received the peak voltage adapter today, so as soon as I get some free time this week I'll get all the items tested that require this adapter.

A bit of an update regarding the misfire:

1. I can 'walk' 1st gear (that is, very slow acceleration)all the way up to 9 grand without any misfire (tried it once though). The instant I give it any decent amount of throttle, though, it misfires.
2. 2nd gear will misfire even with low throttle, and it used to be only around 8000RPM and above. Then it started doing it at 6000RPM, and today it did it a 4000RPM. So 2nd gear is really starting to suck.
3. I can give 3rd gear WOT all the way up to 10,000RPM with zero misfire. I only did it once (to avoid police), and will try a few more times to be certain, but so far, it appears to affect only 1st and 2nd gear.

I'm really hoping it's one of these sensors, because I'm *really* not interested in putting money into internal engine repair >:-(. I already did the compression test (albeit with a faulty gauge) but all 4 cylinders were pretty much identical, so I'm not too worried that is the cause.

 

[David Offor]

When I was getting misfires on my bike, I was getting C24, C25, C26 codes, in dealer mode.
Yours and mine point to coils or possible failing/faulty sensor but I'm changing injectors because of my failed fuel pump and ? Over their serviceability.
Hope you find a bad (cheap) sensor.

 

[Shaun Ketterman]

When I was getting misfires on my bike, I was getting C24, C25, C26 codes, in dealer mode.
Yours and mine point to coils or possible failing/faulty sensor but I'm changing injectors because of my failed fuel pump and ? Over their serviceability.
Hope you find a bad (cheap) sensor.

I've got some more sensor numbers. Take a close look at the tip over sensor, as this one may be bad, but I need someone with the knowledge to confirm:

1. Injectors
a. Resistance - 13.5/13.2/13.4/13.4 (these are all good)
b. Voltage - 12.0/12.0/11.9/11.9 (these are all good)
c. Additionally, the test I did with the motion pro showed good spray and no leaks on all injectors

2. VCSV
a. Resistance -38ohms (good)

3. TPS
a. Resistance: 1.17k closed / 3.9k open (these are both low)
b. Input voltage: 5.1V/5.0V (both tests good)
c. Output Voltage: 1.1V-4.3V (both are good)
d. Additionally, all tests showed smooth increase in numbers when opening the throttle, and smooth decrease in numbers when closing the throttle. Resistance is the only measurement that is off.

4. IAP
a. input voltage: 5.07V (good)

5. Camshaft Position Sensor
a. Resistance: 1.1k (good)
b. Peak Voltage: 1.3V (good)

6. Crankshaft Position Sensor
a. Resistance: 297ohms (good)
b. Peak Voltage: 3.6V (good)

7. Tip Over Sensor
a. Resistance: 62kOhms (good)
b. Voltage: 2.5V
c. Voltage is funky. It should be 2.5V when upright, and 0V when tipped over. Mine stays at 2.5V no matter what I do. Is this bad?

The only thing left to test is the coils, and I need a brand new friggin' spark plug to do the peak voltage tests on them, which, of course, I don't have right now.

 

[David Offor]

I called a Suzuki dealer today and spoke to a seasoned mechanic and he told me that a faulty ckps can cause lots of running problems and that the tests in the book, won't nesassaraly find it faulty.
I fitted the replacement, good set of injectors today, with no difference, to my running, boggy to 3000rpm, then missfires over 9000rpm on 1, 2, and 3 cylinders.
It's great that you are eliminating sensors but make sure that the tests are infallible.
As for the tip over sensor, I don't know but I read on a thread here somewhere, that a resistor can be put in the line and junk the tip over switch, without the resistor the bike won't run.

 

[Shaun Ketterman]

I called a Suzuki dealer today and spoke to a seasoned mechanic and he told me that a faulty ckps can cause lots of running problems and that the tests in the book, won't nesassaraly find it faulty.
I fitted the replacement, good set of injectors today, with no difference, to my running, boggy to 3000rpm, then missfires over 9000rpm on 1, 2, and 3 cylinders.
It's great that you are eliminating sensors but make sure that the tests are infallible.
As for the tip over sensor, I don't know but I read on a thread here somewhere, that a resistor can be put in the line and junk the tip over switch, without the resistor the bike won't run.

How are you determining that it's 1, 2, and 3 cylinders? Are you getting codes?

What the dude told you about the sensors is what I was fearing, but had pretty much already accepted. I am 99.9% I have a faulty sensor, and the tests aren't really showing it. My TPS is funky in the resistance and continuity categories, and my tip over sensor is ALWAYS at 2.5V. Those are the only two that show any signs of failure, the rest are all on the money. Ugh.

Would it be safe to assume (terrible word, I know) that if it IS a faulty sensor, that it would likely be something in the charging/starting system? I.E, camshaft position, crankshaft position, ECM, coils, plugs?

I ordered some new plugs. Going to use one of them to do the coil peak voltage test, and then fit the new one's in the bike. Maybe I gapped them wrong, or dropped one, etc. They are a cheap option to try (even though they are only a few weeks old).

I guess what I can do is just start replacing sensors one by one. For now, I can live with the idle doing what it's doing, but the misfire, or whatever it is, is getting really annoying, especially in 2nd gear.

 

[sixpack577]

How are you determining that it's 1, 2, and 3 cylinders? Are you getting codes?

What the dude told you about the sensors is what I was fearing, but had pretty much already accepted. I am 99.9% I have a faulty sensor, and the tests aren't really showing it. My TPS is funky in the resistance and continuity categories, and my tip over sensor is ALWAYS at 2.5V. Those are the only two that show any signs of failure, the rest are all on the money. Ugh.

Would it be safe to assume (terrible word, I know) that if it IS a faulty sensor, that it would likely be something in the charging/starting system? I.E, camshaft position, crankshaft position, ECM, coils, plugs?

I ordered some new plugs. Going to use one of them to do the coil peak voltage test, and then fit the new one's in the bike. Maybe I gapped them wrong, or dropped one, etc. They are a cheap option to try (even though they are only a few weeks old).

I guess what I can do is just start replacing sensors one by one. For now, I can live with the idle doing what it's doing, but the misfire, or whatever it is, is getting really annoying, especially in 2nd gear.

I know you have alot of different things going on; but when you say "especially 2nd gear", are you sure that it's a misfire there? Not the notorious gen1's 2nd gear failure?
It slips and can feel like an electrical or fuel related problem.
Which of course doesnt explain the idle and rev issues.

 

[Shaun Ketterman]

I know you have alot of different things going on; but when you say "especially 2nd gear", are you sure that it's a misfire there? Not the notorious gen1's 2nd gear failure?
It slips and can feel like an electrical or fuel related problem.
Which of course doesnt explain the idle and rev issues.

Hey six. I'm aware of what you are referring to, but I wouldn't know how to actually diagnose that. I'm using the term 'misfire' because that's what it feels like. The bike just loses power for a fraction of a second, then returns, full force, instantly. I initially thought the clutch was slipping, but when it happens, the RPM's don't surge at all. Of course, the time it takes for the power to cut off and return is a fraction of a second, so it's really hard to say.

With clean injectors, a new pump and filter, I'm confident I've ruled out fuel. Electrical is a lot harder to figure out though. You near San Diego? Come take it for a spin!

 

[Shaun Ketterman]

Just found this thread:

https://www.hayabusa.org/forum/threads/2006-hayabusa-clutch-slip-in-the-powerband.156734/

If you read the OP, and then the 10th post in that thread (also from the OP), they describe my problem perfectly. The only thing mine does different is the 'misfire' occurs at various RPMs. It started at JUST 8 grand, but now happens as low as 4 grand (in 2nd gear). The OP stated that he could clutch-up into a wheelie (I do not have the skills for this), suggesting the clutch was good.

Some of the suggestions from others were:

- Clutch slip (my RPMS do not surge when it happens)
- Popping out of gear / false neutral (when the 'misfire' occurs, I immediately regain full power, there is never a sense of being in neutral)
- Clogged fuel filter (mine is brand new, as is the pump. Injectors are clean as well)
- TIP sensor - This one is a possibility. In another post, I tested my TIP sensor. It should read 2.5V when upright, and 0V when tilted. My sensor reads 2.5V all the time. I can tilt it, hell, I can turn it upside down, still 2.5V. I can hear whatever is inside the box rattling around when I tip it over.

Also, the OP eventually narrows it down to 2nd gear (post 13). Mine definitely does it in 1st gear as well, but I can accelerate SLOWLY in 1st, all the way to the red line, and it shows zero signs of the issue. It's only when I give it decent throttle in 1st gear that I get symptoms.

Also, I responded to that thread...the last post was 2011 so that is probably a no-no, but I'd really like to learn what the fix was, if the OP figured it out.

 

[David Offor]

How are you determining that it's 1, 2, and 3 cylinders? Are you getting codes?

What the dude told you about the sensors is what I was fearing, but had pretty much already accepted. I am 99.9% I have a faulty sensor, and the tests aren't really showing it. My TPS is funky in the resistance and continuity categories, and my tip over sensor is ALWAYS at 2.5V. Those are the only two that show any signs of failure, the rest are all on the money. Ugh.

Would it be safe to assume (terrible word, I know) that if it IS a faulty sensor, that it would likely be something in the charging/starting system? I.E, camshaft position, crankshaft position, ECM, coils, plugs?

I ordered some new plugs. Going to use one of them to do the coil peak voltage test, and then fit the new one's in the bike. Maybe I gapped them wrong, or dropped one, etc. They are a cheap option to try (even though they are only a few weeks old).

I guess what I can do is just start replacing sensors one by one. For now, I can live with the idle doing what it's doing, but the misfire, or whatever it is, is getting really annoying, especially in 2nd gear.

I leave a split pin in the diagnosis plug and ride it hard, until the misfires appear, then the dash records and displays the codes but if you turn off the ignition, you loose the codes.
I've been told that the camshaft sensor, is only used during startup but I don't know if a faulty one could cause your problems.
Your tip over sensor readings are interesting but again, I don't know enough about it or what impact it can have, I thought the bike would either run or not run, if it was faulty?
I hope to get my new stator ckps combo tomorrow or Thursday and will post results as soon as I know if there are any improvements/changes.

 

[Shaun Ketterman]

The shop I took it to test rode it, dude came back and was 200% certain it was the transmission. They said likely a bent shift fork, and it's slipping out of gear.

Good news is, my transmission is still under warranty for another 2 weeks. Took the bike to the dealer and told them the symptoms and what the other shop told me, and man, they *really* didnt want to agree with me.

Long story short, Im taking it back there after work tomorrow. They are going to swap some parts from a parts bike (ECM) and test ride it. Eventually, when nothing they do works, Im going to tell them to open the tranny.

We'll see how it goes...

 

[sixpack577]

Hey six. I'm aware of what you are referring to, but I wouldn't know how to actually diagnose that. I'm using the term 'misfire' because that's what it feels like. The bike just loses power for a fraction of a second, then returns, full force, instantly. I initially thought the clutch was slipping, but when it happens, the RPM's don't surge at all. Of course, the time it takes for the power to cut off and return is a fraction of a second, so it's really hard to say.

With clean injectors, a new pump and filter, I'm confident I've ruled out fuel. Electrical is a lot harder to figure out though. You near San Diego? Come take it for a spin!

I'de love to take a look at it, and my uncle lives in Escondido.
But I'm a few miles away...on the other coast, in Virginia.
Sorry man, but it sounds like progress.
Hopefully it is the transmission, and it's a warranty repair. That way that problem, or potenti problem is gone for good.
But, even if it is jumping out of gear, I don't understand the hanging revs and high idle.
Regardless, if it's under warranty, I'de leave it there until it's right.

 

[David Offor]

The shop I took it to test rode it, dude came back and was 200% certain it was the transmission. They said likely a bent shift fork, and it's slipping out of gear.

Good news is, my transmission is still under warranty for another 2 weeks. Took the bike to the dealer and told them the symptoms and what the other shop told me, and man, they *really* didnt want to agree with me.

Long story short, Im taking it back there after work tomorrow. They are going to swap some parts from a parts bike (ECM) and test ride it. Eventually, when nothing they do works, Im going to tell them to open the tranny.

We'll see how it goes...

Sounds really interesting, did the guy who rode the bike, offer any explanation or how your bike could have a bent shifting fork or how it could affect the bikes running so much?

 

[sixpack577]

I'm thinking 2nd gear is bad.
I doubt the shift fork(s)are damaged.
If they were, there should be noticeable shifting problems.