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Discussion Starter #1
Hopefully I can find someone that knows better than me on this one... I have an 09 Dl1000 with 20k miles which runs and drives great. It does occasionally have what feels like a miss or stumble at full throttle from 8k - 9k RPM. It’s difficult to describe other than it doesn’t pull smoothly when this phenomenon occurs, maybe 5-6 very brief surges while accelerating which I can only guess are misfires on one cylinder. It normally pulls fine and has plenty of power and pulls strong through the entire rpm range, although I don’t run it to the redline that often. I have no FI light or codes in dealer mode.
So far I have:
Replaced the TPS and adjusted to spec per the FSM.
Replaced the throttle bodies and injectors
Synchronized the throttle bodies
Synchronized the secondaries
Tested all sensors and verified in spec per service manual
Cleaned all grounds in ignition circuits.
New NGK iridium plugs
External fuel filter mod
Fuel pressure test and flow check within spec
Replaced ECU
Added ATRE
Added power commander 5 and remapped

I haven’t been able to pull the stator cover cap to check valve clearances because the cap is stuck and rounded the hex, so that’s ordered and on the way. Otherwise it’s a solid bike and never misses a beat under 8k. My OCD perfectionist side needs to figure this out though.
Thanks in advance for any help or insights. ?
 

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Two thoughts came to my mind, fuel quality and injector issues. I'm guessing you've replaced the fuel with fresh. There have been reports of injector issues on older stroms. Maybe look into cleaning / replacing them.

Two additional thoughts, GW talked about weird things happening with a poor ground, so clean and treat the engine ground and battery terminals. The other thing is to check the wire harness bundle connectors for any corrosion.

Sent from my SM-G930V using Tapatalk
 

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Discussion Starter #3
Definitely a thought I had. Replaced the injectors. No difference.
Fuel never sits in the tank more than a few days. It’s my daily driver.
 

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Possibly a faulty coil. When coils fail they are often fine at low rpm's but fault at higher revs.
You have certainly already worked on all the most common culprits. Are you confident that the two rubber boots connecting throttle bodies to airbox are securely fitted?
 

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Discussion Starter #5
100% certain the throttle bodies are secure to the boots and airbox. I’ve made a good effort to make sure everything is properly adjusted and sync’d and usually verify TB sync any time I have the airbox off for any reason. This one is definitely throwing me off.
One more symptom I’ve thought of is that it doesn’t do it on short rides <25 miles. It doesn’t seem temperature specific but more sensitive to the duration of the ride. I chased a buddy on a KTM for 125 miles, my Vee didn’t act up any until about 80 miles into it or so. Again no FI light, no codes. Just an annoying miss on what should be a bulletproof bike.

Thank you for your help... I’ll look and see if I can’t find a different set of coils to try. I did check and the resistance through primary and secondary are equal and within spec on both coils, both boots seated tight and properly on the plugs...
 

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Well that should eliminate faulty coils as it would most likely occur all the time.
Can I now suggest a blocked fuel tank vent? Check it by putting your spare key in the tank cap and unseal the cap when the missing occurs.
 

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Discussion Starter #7
I went ahead and ordered a newer set of coils just to rule that out for sure. The tank vent being clogged, that’s a brilliant suggestion I haven’t tried. I’m excited to check it out in the morning. Thank you! I’ll let you know what I find...
 

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Sure you aren't bouncing off the rev limiter somewhat, I mean that's high RPM's for this engine.....this isn't a racing bike? :) The big Katoom and the Ducati Multistrada are still building serious HP and speed at those RPM's, but this isn't a 150HP plus engine designed for performance.
 

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Discussion Starter #9 (Edited)
I’ve certainly hit the rev limiter, and as I said before it isn’t a common thing to go out and run it as hard as it’ll go.... that being said, the redline is 9500 and it normally runs smooth as silk if I try to take it there. Definitely aa very different feel. The misfire in question is much less pronounced than the rev limiter and doesn’t cease the acceleration, it’s just noticeable and annoying.
I agree there are plenty of faster bikes, but I have no problem taking the Vee to its limit. Suzuki engineers went to college a lot longer than I did.... they decided the redline on this bike.
Don’t forget where this power plant came from... this is an evolved TL1000 engine after all, even if it is turned down to reasonable.
 

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Discussion Starter #10
Well that should eliminate faulty coils as it would most likely occur all the time.
Can I now suggest a blocked fuel tank vent? Check it by putting your spare key in the tank cap and unseal the cap when the missing occurs.
I was so ready for that to be the answer, but the venting system in the cap is remarkably clean and free of obstructions....
Going to clean it up and put it back on... still a mystery. Waiting on those new coils...
268327
 

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Discussion Starter #11
Well that should eliminate faulty coils as it would most likely occur all the time.
Can I now suggest a blocked fuel tank vent? Check it by putting your spare key in the tank cap and unseal the cap when the missing occurs.
 

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Discussion Starter #12
Well that should eliminate faulty coils as it would most likely occur all the time.
Can I now suggest a blocked fuel tank vent? Check it by putting your spare key in the tank cap and unseal the cap when the missing occurs.
Just in case I went ahead and cleaned up every vent passage with the next size drill bit. A ride later to test for improvement...
268331
 

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I once had a bike that was a problem at high RPM's but it was constant not like yours.

It was only a single cylinder and one day totally frustrated I banged the spark plug on the engine case and closed the gap a little.

I could not tell you just how much because I never measured it but all my problems disappeared instantly.

Do you have a volt meter fitted and are you getting a good constant 14+ volts when the problem shows up ???
 

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Discussion Starter #14
I once had a bike that was a problem at high RPM's but it was constant not like yours.

It was only a single cylinder and one day totally frustrated I banged the spark plug on the engine case and closed the gap a little.

I could not tell you just how much because I never measured it but all my problems disappeared instantly.

Do you have a volt meter fitted and are you getting a good constant 14+ volts when the problem shows up ???
So I’ve been thinking along the same lines. I cleaned all the grounds around the coils and verified proper resistance through the primary and secondary. It seems like a weak spark. I replaced the plugs with NGK iridium and verified proper gap before installing them. I have a relatively new MOSFET rectifier that puts a beautiful 14.3v out all the time consistently. I do have a voltmeter installed so I can always see if there’s a problem there.
It’s incredibly difficult to diagnose being as inconsistent as it is. New coils will be here this weekend, just in case something in the boot or wire is bad.

Thanks for your help!
 

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When I have a misfire to find I start to play with things that are free, my first point of call is always the air filter...
I remove it and ride the bike looking for any changes in behaviour, this helps fee up the air, I then stuff rags into the airbox to restrict the amount of air.
This is unlikely to solve your problems but it can help send you down the right path, if it is a fuel issue you normally see a change but if it is electrical there is seldom a change.
I know you tested your fuel pump but I suspect it could be the problem and you could ask if any member here is willing to change fuel tanks with you for a bit while your testing, again it is free.
You have tested your sensors and they are within spec, have you searched part numbers to ensure there have been no upgrades to these parts ? again free.

I purchased a car off it's original owner and it had a miss just above idle, being a manual it was a pain, I spent 12 months checking and testing and could never nail down the problem, I decided I would start changing sensors one at a time, I walked into my local dealer with a yellow sensor and said I want one of these please, when he looked it up & that part had been superseded, it was now blue to indicate the difference, that new part & a few $ solved all my problems, years later I was in a auto electricians shop and he had the exact same car in there with the hood open, I spied it had the yellow sensor in place so I started a conversation, it turned out it was his personal car and his solution to the miss was to constantly clean his injectors, I suggested he get a blue sensor, he rang me a few days later and asked if I would like a job, the blue sensor also fixed his miss.

Check for soft vacuum hoses, a mate asked me to look at his car, it worked great on the flat and small hills but would not climb bigger hills though it would go up them in reverse, the car had a manual fuel pump and enough restriction in the fuel filter that the rubber fuel line would collapse starving the motor of fuel, but at lower RPM's on smaller hills and going in reverse the car ran fine.

Again free but time consuming I would then go old-school, a compression and leak down test to ensure there is no mechanical reasons and fit a pair of vacuum gauges, leave them mounted for a few weeks and keep a close eye on them looking for differences when the bike is fine and when it is not.

It is obvious you know what you are doing but sometimes a fresh outlook or going back over & retesting gives the answer, I would check that fuel pump again
 

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Discussion Starter #16
I certainly appreciate your fresh perspective! I know there is no substitute for experience and the best place to find people with that is forums such as this.

I’ll take a look at the fuel pump again and double check the sensors while I have the tank off to replace the coils.
Replacing sensors one by one is the other direction I’m going in my head. They all affect the fuel mapping, especially the CKP, IAP, and TP sensors (per the service manual). I replaced the TP recently so it’s new and runs noticeably better. Even the misfire seems less pronounced, l thought I had solved it for a while but it’s still there now and then.
Thank you for your thoughts! I’ll double check part numbers son sensors and recheck the fuel pump next.
 

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I will attempt to explain why I'm leaning towards the fuel pump.

If the pump is in great working condition there is always enough fuel pressure & volume to keep the bike happy at any throttle opening and any RPM.

When the pump is giving problems it will start struggling to supply pressure or volume at higher throttle openings and higher RPM's like your bike.

The thing is when the pump is struggling if you close the throttle just a little or for a split second or two it can allow the pump just enough time to recover pressure or volume.

That is why the problem can be random, with most other things the problem is there or it is not.

Now I am on the other side of the world, I have never ridden the bike and there are a thousand things it could be but if someone was kind enough to swap tanks with you my theory could be tested quick & easy.

I once had trouble with a KDX200 that had no spark, I found the same bike for sale locally and offered the seller a carton of beer if he would allow me to try my ECU in his & his in mine, for a few dollars I had the answer I needed and made a new friend too.
 

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Discussion Starter #18
I will attempt to explain why I'm leaning towards the fuel pump.

If the pump is in great working condition there is always enough fuel pressure & volume to keep the bike happy at any throttle opening and any RPM.

When the pump is giving problems it will start struggling to supply pressure or volume at higher throttle openings and higher RPM's like your bike.

The thing is when the pump is struggling if you close the throttle just a little or for a split second or two it can allow the pump just enough time to recover pressure or volume.

That is why the problem can be random, with most other things the problem is there or it is not.

Now I am on the other side of the world, I have never ridden the bike and there are a thousand things it could be but if someone was kind enough to swap tanks with you my theory could be tested quick & easy.

I once had trouble with a KDX200 that had no spark, I found the same bike for sale locally and offered the seller a carton of beer if he would allow me to try my ECU in his & his in mine, for a few dollars I had the answer I needed and made a new friend too.
I have another pump on the shelf, I’ll swap it out and see while I have the tank off. I originally thought the fuel pump as a culprit, but that’s the time the TPS went out... When I had the new pump in, the pressure regulator popped off inside the tank. I put the original pump back in as the TPS got replaced, and pressure tested the original pump to about 46 psi, the strong side of within spec. It’s free to swap the pump out again, so I’ll give it a try. ?
 

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Discussion Starter #20
For a tip on securing the pressure regulator from popping off, External Fuel Filter modification.
For sure! I’ve done the external fuel filter mod and secured the regulator with a few zip ties this time. Works like a dream.
Thank you!
I’ve scoured the entire forum and tried just about everything anything has done to their Vee. They’re all great improvements.
 
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