Kawasaki Z1000 Forum banner
1 - 20 of 53 Posts

·
Registered
Joined
·
46 Posts
Discussion Starter · #1 ·
2003 Z1000
42'000kms
K&N Air filter
Air filter box mod
Danmoto slipons
stock tune/ECU.

Fixed an issue the other week with my fuel breather hoses, and since my bike has never ran better, I've been riding the absolute crap out of it. And so now I have a new issue that has me scratching my head.

After a long ride, I went to gun the throttle and instead of surging forward, the bike just bucked and choked. Long story short, I figured out I could fix the problem for a bit, by flipping the kill switch on/off, while the bike was still coasting.

Once I flip the kill switch off, and the bike is "on" again, it instantly has max power. I might even risk saying, an absurd amount of power. Now that I've been riding this issue for a couple days, I've noticed that the power is gradually fading, until it starts to bog in the high rpms. If I continue to ride, the "usable rpm's" get's smaller and smaller, untill it's choking at 5K instead of 8K. Again, restarting the bike results in instant, full power again. have to restart probably every 20 mins of hard riding.

Thoughts? Is my stator going? Is the fuel pump going? Just seems so weird that restarting, or even just flipping the kill switch restores power instantly.

Any advice would be appreciated!
 

·
Registered
Joined
·
498 Posts
I'd be looking at electrical connections for a start. Take a peek into the handlebar switches,kill switch etc. Also the clutch cutout connector and side stand switch.

It's going to be a process of elimination.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #4 ·
Thanks for the input. Will be looking over stuff today. Plan on removing the stator cover to take a peak, the previous owner thinks that's the issue, but I'm not so quick to spend money these days.

I also noticed that when I pull the clutch in and hold the throttle, I can smell excess fuel, so I'm more leaning towards it being a spark issue and not the fuel pump cutting out. ( 2:03 in the video )

I've read about clutch and stand switches, my symptoms just don't relate. Everything I've read about those going bad is vibration or something at a certain RPM. My bike starts to die specifically when ridden hard, and sometimes takes longer than other times. The problem also continually worsens until "resetting" the bike. If you're light on the throttle you may never heat things up enough to have it choke on you.

I'll see how the stator looks. Would be great if I saw something visual, although I'm not usually that lucky when it comes to electrical issues ha.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #6 ·
I watch the video and the thing that pops into my mind is that the 2ndary throttle valves are not opening up
Interesting. They're electronically controlled? Is there any way that I can check this? If I remove tank/ airbox, can I simply turn the key to "On", twist the throttle and visually see the valves open? (or not open). Though again, only happens when you'er heavy on the throttle for a bit.

Thanks for the reply.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #8 ·
Kill switch looks good. Must have something to do what what exactly the kill switch, does. Something is being reset, so it clearly isn't really heat related, since I can be going balls out, it starts choking, and then instantly is good again after flipping the switch. (for a little bit anyway).
85093
85092
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #10 ·
Thanks man, everything seems good in that regard. Electrical problems suck.

I was riding today and was gunning it, when all of a sudden I lost all power.....or so I thought. I pulled in the clutch and noticed the revs instantly drop to idle and stay there. Once I release the throttle they jumped up and down again, to match the throttle position.

So I'm gonna check my TPS. Maybe it's being intermittently weird. And no, it's not necessarily after it's warmed up I'm finding. TPS is my next check.
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #11 ·
thought this was interesting, page 119 of service manual. I'm not getting any codes, but it seems that if the ECU is detecting a throttle sensor problem, it'll put the engine at closed throttle. If I understand it correctly.
85097
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #12 ·
Haven't gotten any closer to solving the issue. I took apart and cleaned my Gas Cap. Had some slight buildup but no clogging of any kind.

I don't have the Adapter Harness to test the TP Sensors, but when I google fault TPS symptoms, that's not what's happening.

The Kill switch JUST interrupts the ignition system correct? So, if the bike is running and you hit the kill switch, the Fuel Pump is still primed? I'm trying to figure out why flipping the kill switch (turning bike off and on) fixes my surge/misfire/bucking issue.

I was practicing wheelies yesterday and also noticed when I was in second gear and pinning it for a second to test, that the revs wouldnt go above 9K. Came to a stop, clutch in, held throttle to hit limiter, and it wouldnt go past 9K. closed the throttle slightly, and it would hit limiter. Seems like the Throttle is opening past the up and down point and closing again? hoping I can adjust this. May or may not be related to my main issue.

Not at all ruling out Secondary Throttle Body failure, I just don't understand why flipping the kill switch fixes the problem. Havent been able to find any other motorcycle of any kind with this identical problem. Unless no one else tried flipping their kill switch while riding. Maybe I'm just weird and found an unknown temporary fix. Regardless, I don't have money to throw at a dart board so trying to narrow things down.

Probably worth testing the cam sensor and crank sensor. But, I thought those things usually just fail. The Quest continues.
 

·
Registered
Joined
·
471 Posts
so no flashing FI light? maybe a clogged or inadequate pressure on the fuel rail or failing fuel pump? if it was a spark issue, as in bad coil or reg/rec then you'd get backfires from unburned fuel, shuddering and dying without backfire kind of points to lack of fuel?
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #14 ·
so no flashing FI light? maybe a clogged or inadequate pressure on the fuel rail or failing fuel pump? if it was a spark issue, as in bad coil or reg/rec then you'd get backfires from unburned fuel, shuddering and dying without backfire kind of points to lack of fuel?
Good thought. I also wonder, if the pump is nearing the end, that when I fixed the breather hoses on the tank and the pump could actually pull easily, that I quickly burnt it out because I was riding so hard (too much fun tho).

As you can see in the video, the bike starts instantly every time. Can anyone give their theory as to what the Kill switch is resetting? because that's the catch here. The engine can be at 100 degrees celcius (212 F) and start to stutter/hesitate, but then I'll switch it off on and instantly 100%, quick throttle response. But then it will start to slowly degrade and get worse.

Maybe the Sub Throttle servo is on it's last legs?I've seen assemblies on eBay for 250$ CAD plus shipping, not the most expensive thing in the world, but again, trying to make as good a guess as I can before spending money.

Appreciate the response!
 

·
Registered
Joined
·
471 Posts
The kill switch is not resetting anything, the EFI computer on these bikes is about as complex as a late 1980's Toyota Corolla. If anything, all the kill switch is doing is killing the engine and possibly allowing proper fuel pressure to build once again when restarted.

The fuel pump has this thing in it called the fuel pressure regulator, looks like the image below. I believe on our bikes it;s built within the pump shroud. It's only job is to prevent the pump from building too much pressure and blowing the hoses. It basically opens after a certain bar of pressure and vents fuel back into the tank. Most people replace this when they replace a fuel pump as this is a wear item that does tend to fail. It could be the the FPR is venting at lower pressures then it should and starving the bike of fuel at higher fuel requirements.

There is also a fuel pressure sensor on the bike. If you build an OBD harness you should be able to read this value via a bluetooth dongle and an android phone and see how fuel pressue is acting when the bike is cutting out.

Don't spend money without doing proper diagnostics. The manual would state what kinda voltage and/or resistance you should be reading off both the throttle and sub throttle, or even datalogging via the aforementioned diagnostics. Definitely diagnose and be sure of the culprit before shooting the parts cannon at the problem...

85117
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #16 ·
The kill switch is not resetting anything, the EFI computer on these bikes is about as complex as a late 1980's Toyota Corolla. If anything, all the kill switch is doing is killing the engine and possibly allowing proper fuel pressure to build once again when restarted.

The fuel pump has this thing in it called the fuel pressure regulator, looks like the image below. I believe on our bikes it;s built within the pump shroud. It's only job is to prevent the pump from building too much pressure and blowing the hoses. It basically opens after a certain bar of pressure and vents fuel back into the tank. Most people replace this when they replace a fuel pump as this is a wear item that does tend to fail. It could be the the FPR is venting at lower pressures then it should and starving the bike of fuel at higher fuel requirements.

There is also a fuel pressure sensor on the bike. If you build an OBD harness you should be able to read this value via a bluetooth dongle and an android phone and see how fuel pressue is acting when the bike is cutting out.

Don't spend money without doing proper diagnostics. The manual would state what kinda voltage and/or resistance you should be reading off both the throttle and sub throttle, or even datalogging via the aforementioned diagnostics. Definitely diagnose and be sure of the culprit before shooting the parts cannon at the problem...

View attachment 85117
Thanks so much, really appreciate the info!

Lol simplicity is good, I like simplicity.

I had cleaned out my gas cap because I had thought ya, maybe flipping the kill switch released the fuel pump for a second, allowing proper vacuum to restore and then slowly builds up again as I keep riding. But, all seems good ventilation wise.

Never heard of building an OBD harness but I'll give it a google, sounds incredibly useful.

I'll take out the meter and do some tests. Need to make or snag an adapter harness to check the TP Sensors, I could only fit 2/3 gator clips into the clip.
 

·
Registered
Joined
·
471 Posts
Thanks so much, really appreciate the info!

Lol simplicity is good, I like simplicity.

I had cleaned out my gas cap because I had thought ya, maybe flipping the kill switch released the fuel pump for a second, allowing proper vacuum to restore and then slowly builds up again as I keep riding. But, all seems good ventilation wise.

Never heard of building an OBD harness but I'll give it a google, sounds incredibly useful.

I'll take out the meter and do some tests. Need to make or snag an adapter harness to check the TP Sensors, I could only fit 2/3 gator clips into the clip.
just back probe the connector using a back probe pin. Look at this thread for the pinout for the diag connector. The Z1000 uses the same 4-pin K-Line connector via KWP2000 protocol as the Ninja400, NOT Can-Bus like the ZX6/10r bikes with the 6-pin connector


85118
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #19 ·
So I went to the junkyard, pulled an OBD2 socket from an 03 Forester, re-arranged the wires the configuration according to the DIY Code Reading Guide, and spliced it in. It was slightly tricky because the Ninja400 wire colours are different, but I luckily was able to figure it out (only 4 wires, too) going by the wires from my gear indicator plug.

Unfortunately, either I need to simply swap the K-Line and L-Line, or, my reader (Innova 3030e) doesn't read KWP-2000, which I'm thinking is the case because I cant find any information saying that it does. So, while it powers on, after blinking "read" for 20 seconds or so, it just says "Error". Will update once I get a new OBD reader. will most likely get a bluetooth one.

As of now, still no answers yet.

85121
 

·
Registered
Joined
·
46 Posts
Discussion Starter · #20 ·
Used a BlueTooth Innova 3211a OBD2 Scanner and it worked great. Unfortunately, no codes. Switched to Scotch double sided tape to attach the socket to the frame. Unfortunately, The seat doesn't close with the OBD2 scanner inside, and I don't feel like cutting the fins off the seat :p But I'm not worried about it, will just make a cap of some kind.
85122
 
1 - 20 of 53 Posts
Top