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Somebody correct me if I'm wrong, but isn't it true that the bike would not require as much fuel at wot in first gear as in sixth gear?
 

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Somebody correct me if I'm wrong, but isn't it true that the bike would not require as much fuel at wot in first gear as in sixth gear?
Fuel flow is a function of power being made so the gearing is not important. If you are at the same rpm/throttle position the horsepower and fuel flow are about the same. Now using WOT in 1st can difficult not only for control (keeping the wheel down) but also that you'll hit red line very quickly.
 
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I saw John fix a similar problem on the side of the road.
It was a kinked fuel line.
It was actually in the garage. :ROFLMAO:

But very good point. @Txgixxer690 make sure the hose from the fuel pump to the fuel rail is not kinking when you lower the tank. The fitting on the pump can swivel down when the tank is raised but stay stuck there when you lower the tank.
 
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Fuel in 1st and 6th, and the amount of power is the same, but the use of the power is different. Basically, 100lb on a short lever vs a long lever. If you are only generating 80lb of force, you'll notice it on the short lever before you'll notice on the long lever.
 

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Discussion Starter · #27 ·
Alright, well I guess I can rule out the fuel pump...

Bought a $50 Maddox gauge from HF, which may be a hair off on its reading, but it read 45-46 psi the whole time... including while I'm pinning it and its bogging.

I'm relieved and irritated at the same time. After reading posts about the pump not holding up under wot load and a new pump fixing it, I thought that might be my issue. Was dreading that being the case though with the cost of a new pump.

I guess I can pull injectors and either go through them myself or have them professionally done, but I find it hard to believe that my injectors would be clogged since I didn't get anything but clean gas when I back flushed the fuel filter... :unsure:

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Discussion Starter · #29 ·
It was actually in the garage. :ROFLMAO:

But very good point. @Txgixxer690 make sure the hose from the fuel pump to the fuel rail is not kinking when you lower the tank. The fitting on the pump can swivel down when the tank is raised but stay stuck there when you lower the tank.
Fuel line doesn't appear to be kinking.. it rotates a little as I lower the tank and doesn't seem to be bending any more than the way its molded..
 

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Is that the stock exhaust? Are we sure the SET isn't partially closed? Have you pulled the spark plugs?
 

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Is that the stock exhaust? Are we sure the SET isn't partially closed? Have you pulled the spark plugs?
He said earlier he checked the SET valve.

What are you thinking about the spark plugs? Just their condition or what what they might show? (sooty, dry, oily, etc)

What do you think about one or more of the secondary injectors being stuck closed? Do you think that might produce similar symptoms?

Can the secondary throttle plates cause symptoms like this? I just don't know.
 

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@Txgixxer690 when the bike "bogs" does it still run pretty smoothly or do you hear/feel any uneveness in the engine firing?
 

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Discussion Starter · #33 ·
Is that the stock exhaust? Are we sure the SET isn't partially closed? Have you pulled the spark plugs?
It is stock and cables have been removed so valve is constantly open I believe. Haven't pulled spark plugs since I replaced them a few weeks ago, shortly after getting the bike.

@Txgixxer690 when the bike "bogs" does it still run pretty smoothly or do you hear/feel any uneveness in the engine firing?
Feels/sounds fine until wot. Spits and sputters when pinned but don't know/think that its misfiring. Could be possible I guess, but I would think I would notice that without going wot..?

When testing it around the house ill just throw it in 2nd and pin it and it stays around 40 mph and whatever rpm (i think around 5-6k). Last night I was on the highway hitting it in higher gear/speed/rpm again. It did not hold speed, not sure about rpm. I've held it pinned for a decent length to see if it would eventually clear up but it doesn't. I'll record it if I can find a way, but I don't have a gopro or anything right now.
 

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I'd put an eye on the SET and just be 100% certain.

Can you repeat the behavior in neutral? If so, if you go 50-70% throttle can you get it to the redline without issue? If so, I'd unplug the TPS and put a meter on it and make sure it's reading linear and not going back down near the top end. (FYI, I've seen the secondary TPS on the older bikes which is identical to the primary on your bike exhibit this behavior.)
Also, are we certain the secondary injectors are doing their thing?
 

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Discussion Starter · #35 ·
I'd put an eye on the SET and just be 100% certain.

Can you repeat the behavior in neutral? If so, if you go 50-70% throttle can you get it to the redline without issue? If so, I'd unplug the TPS and put a meter on it and make sure it's reading linear and not going back down near the top end. (FYI, I've seen the secondary TPS on the older bikes which is identical to the primary on your bike exhibit this behavior.)
Also, are we certain the secondary injectors are doing their thing?
I will look at the SET valve again today. It does not have any problem in neutral. Under load at wot is the only time it happens. When riding I can get to redline and speed in all gears as long as I don't roll on the throttle all the way. If I do roll on it too much and it bogs I just let off a hair and it accelerates fine, just not quite as quick as it could if it didn't bog at wot.. :rolleyes:

I put a new TPS sensor in it around the time that I did the plugs, just to see if it would fix the problem. I am going to throw it in dealer mode again today and check and see where the dash is, and if it fell back down to _C00... but adjusting it back to the correct -C00 position didn't fix my issue last time and I'm not expecting it to. I just want to make sure it's in the right position. I can look into putting a meter on it to see what I find, but I'm not sure exactly how to run that test. Does the service manual explain it?

I am not certain on the injectors. Thats the last part of the fuel delivery system that needs to be checked I guess.
 

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Discussion Starter · #36 ·
Alright, I have the bike here at work with me so I went out on my break. SET valve is always open. I realized that my phones camera is not blocked by the phone mount, so I adjusted the mount so my phone could show the tach and took a short video, link below.

Vid shows me pinning it in 2nd for about 15 seconds.. timestamps ~ 0:16-0:32. The little acceleration at the end is when I rolled off the throttle and got out of the bog zone.


This evening I'll be checking tps again, then probably pull the plugs and take a look at them, then pull injectors I guess.
 

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Good video and captures just what it is doing.

It sounds and pulls good right up to 6k rpm. At that point it does not sound like one cylinder is a problem but all are not producing more power.

Getting a bit of power back by rolling off the throttle is a pretty classic indicator of a lean mixture issue.

I've always heard that the secondary injectors come into play right around 6k rpm so I wonder if that is the issue?

I've also read, but not checked myself, that you can see the secondary injectors spraying by looking down the throat of the throttle body with the airbox removed.

What do you think @Chuckster? This sounds like a new one to me.
 

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Discussion Starter · #38 ·
Good video and captures just what it is doing.

It sounds and pulls good right up to 6k rpm. At that point it does not sound like one cylinder is a problem but all are not producing more power.

Getting a bit of power back by rolling off the throttle is a pretty classic indicator of a lean mixture issue.

I've always heard that the secondary injectors come into play right around 6k rpm so I wonder if that is the issue?

I've also read, but not checked myself, that you can see the secondary injectors spraying by looking down the throat of the throttle body with the airbox removed.

What do you think @Chuckster? This sounds like a new one to me.
I would say it sounds and pulls good right up to when I fully twist the throttle... not necessarily a specific rpm. In the video, yes... but thats just the typical speed and rpm I am at by the time I have the throttle fully open in 2nd gear.
 

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Discussion Starter · #39 ·
In talking with my dad and discussing the issue, he thinks its an issue with the electronics on the bike even though it hasn't thrown any codes. His reasoning being that it only happens at wot, in all gears, and is not only at a certain rpm. He said something along the lines of "Something is telling the computer to cut fuel or something when at that throttle position."

When I called the dealer the other day and explained the situation and then asked what other possibilities there could be he mentioned the secondary throttle valve servo. He then of course proceeded with saying that is a possibility that comes to mind but id really have to bring it in and sign for an hour of labor to have them diagnose and find out. I'm pretty sure that I mentioned the fact that it hasn't thrown any codes too, so...

What do yall think? Have yall read or heard about the electronic controls of the fuel delivery system being the problem with no codes being thrown?

Everything I seem to find online where the electronics are the issue have had a code thrown..
 

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Which is why I said put a multimeter on the primary TPS and see what it's really doing.... but after seeing the video, I'm leaning away from the TPS being an issue.

Personally, I'd like to see that video again, but get it into 5th or 6th at 3000rpm and hammer it. I want to hear it at WOT and climbing slow through the band to 6000rpm.

This is where speculation can get you on the wrong path, and without knowing with 100% certainty what the software does, speculation is all we have.

To your question, yes. Especially on the k6-k7. The charging system is a weak link on these models and can cause damage to the ECM. However, that usually presents with behavior more erratic that what you have.

15 years I've been on this forum and we've seen a lot of weird shit. Dropping power abruptly right at 6k provides a starting point. If we assume the ECM is undamaged, that leaves us with inputs. I think we can rule out fuel delivery. A fuel problem would taper off in power, even if it did so quickly. This is too sharp for that, and you've done testing. So what does that leave? From experiences here, the one issue that baffles everyone is crank sensor issues. We've seen all kinds of weird behavior and no codes. Those situations end up being drawn out over months until the owner gets so frustrated they throw money at it. The sensor basically picks up a frequency, and if it's gotten slow to respond, that could explain the hard edge. I would expect that kind of issue to also show up in neutral, which you say it doesn't.

Before we go there, my gut is telling me it's something stupid simple. Clutch switch maybe? You can start the bike, so obviously it's able to close, but is it opening? Kickstand up, in neutral, and don't pull the clutch. Does it activate the starter?

Onto the secondary injectors (above, thinking they come on only with the clutch released???). I agree with @rv6john. But again, I don't know what the software is doing. Does it drop pulse from the primaries and used combined spray from primary and secondary, or does it use the secondary injectors as supplemental? I don't know. So, simple test, Unplug one of the secondaries and see if it codes. What troubles me here is that the ECM has multiple grounds. Everything is controlled by the ECM by the ECM providing that component with a ground. So, what if the ECM can see the injectors (no codes), but the ground it's trying to link the injector to is bad? Sadly, that level of wiring detail isn't provided in the service manual.

Honestly, I hate problems like this. Usually, you just have to start a process of elimination. You know any groups of riders where someone has the same bike? If possible, put your ECM into an otherwise known good bike. You'll know if your ECM is good or not.

Lastly, I have another question for you. It sounds like you bought the bike in this condition. You also said the SET was permanently disabled yet had no codes? There's a few methods to do that. Being a used bike, we don't know what kind of fuckery has happened with it, so a full review of the wiring is in order. Pulling a specific pin from the ECM connector was a popular method. Did that perhaps cause another issue? Did the previous owner try to flash it and jack something up? All of these types of issues are on the table.

If this bike were in my garage, I'd want to put your ECM in another bike as step #1. Eliminate it as a problem. Then, #2, out would come the beer, the manual, and the multimeter. I'd test every single wire that had to do with the secondary injectors and all the grounds for the ECM. I'd also inspect the wiring harness for anything non-factory.

I don't have a k6, or I'd say ship me your ECM. Maybe another member would offer that to you if you don't have someone local. I know I would have a problem shipping mine to a stranger, but there's several members here I would trust.
 
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