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Discussion Starter · #1 · (Edited)
So, I got a FI error on my bike - stuck a paperclip in it to get to dealer mode, and found out it was c28. Secondary throttle valve actuator. When I read the error I did some troubleshooting with the actuator, and noticed it isn't moving back like it is supposed to - instead, it just swings to wide open, and in doing so, it turns on the fast idle and it starts idling at 3500 RPM. Normally, the STV has two motions when you turn the bike on - however, mine is only going through one of the two movements.

I have checked voltage, and I have checked the STV position sensor's resistance. I set it to as close to within range of TLRMan's recommended settings as I could. Still, no luck.

So, being the enterprising person that I am, I started fidgeting with the butterflies and the STV actuator "rod" (the rod that goes through the actuator w/ the 10mm nut on the end, and the mechanism for pushing the fast idle cam). I found out if I manually set it to wide open with the bike off, then turn it on, the STV's move twice, like they are supposed to, and the FI code goes away. Movement of the STV position sensor then changes the position of the STV's, too. Seat of my pants testing confirms, that the STV's do work when I do that.

However, it doesn't always kick off the code, and the STVA doesn't always do it's second movement back like it is supposed to when I manually set it to the resting position it's supposed to revert to. A third of the time it sticks in WOT, a third of the time it sticks fully closed and my bike becomes asthmatic, and the other third of the time, it works perfectly.

So, does anyone have any ideas as to what is going on? Does the bike need to read the correct resistance at startup from the STV position sensor to move them closed and open again, and that is why it's giving me issues with it being stuck on fast idle until I manually move the plates? Is my STVA dying?

Does anyone know of a solution to removing the secondary throttle valves, rods, and servo, but keep the fast idle mechanism? This is an '03 SV1000, so I'm game to buy one of the later year bigger throttle bodies and fudge around with it to try out any ideas. Thanks!
 

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Ah.....another STV victim.:) The bike really doesn't need them as they only restrict the airflow sometimes more than others, but if they malfunction it's no good. You want to keep the 'FI' light off for the computer to run in the normal vs limp mode.

Easiest way out for you would likely be a cheap set of TB's off of Ebay. Mine came complete with all sensors and injectors for a stupid $25!! If you can find a similar set...get them and now you can troubleshoot any induction problem. On that one...I'd stick the whole set on and call it good. You can swap the troublesome STV motor too if you'd like to keep the rest of the system you have.
 

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If it were a 650, I'd say you can have mine. :)

I removed the whole STV system and extra metal, then added some electronic foolery to keep the ECM happy. Thank you Zoran and TWFracing! To order one for the 650, email Zoran at [email protected] or read more about them here.

Send a PM to DEcosse. He is now making them for the 1000.



EDIT: Here's what mine look like now.... :naughty:

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Discussion Starter · #4 ·
If it were a 650, I'd say you can have mine. :)

I removed the whole STV system and extra metal, then added some electronic foolery to keep the ECM happy. Thank you Zoran and TWFracing! To order one for the 650, email Zoran at [email protected] or read more about them here.

Send a PM to DEcosse. He is now making them for the 1000.
I found a schematic for it online and I was thinking about etching and reproducing it; the only thing I'd be concerned about, like I said, is the whole "fast idle" thing Suzuki has going on and how that would interfere with the engine coming up to operating temperature or running in the winter. How's yours do in cold weather? :vroom:?

Also, how do you like the pods? I've been considering it since my tanks raised to (maybe) increase top end, but I know the airboxes are "tuned" to create extra power at certain levels of air intake to straighten out the powerband... I had my snorkel removed for awhile, I just put it back on and it's actually a bit of an improvement I think?

... and why is your battery not under the seat?
 

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I found a schematic for it online and I was thinking about etching and reproducing it; the only thing I'd be concerned about, like I said, is the whole "fast idle" thing Suzuki has going on and how that would interfere with the engine coming up to operating temperature or running in the winter. How's yours do in cold weather? :vroom:?

Also, how do you like the pods? I've been considering it since my tanks raised to (maybe) increase top end, but I know the airboxes are "tuned" to create extra power at certain levels of air intake to straighten out the powerband... I had my snorkel removed for awhile, I just put it back on and it's actually a bit of an improvement I think?

... and why is your battery not under the seat?

I just did this mod and there haven't been any cold days. I did start it up when it was about 55° the other morning and it did fine. Keeping it in N seems to give it a bit faster idle. It never did it before, (so I know it's not clutch/drag related) but maybe it's something built into the new electronics. Even after warmed up, there's a noticeable bump in RPMs in N. My tach isn't working, but I'd say it increases about 150ish

Pods are OK. Not sure they are the optimal design for performance or filtration, but they're cheap and small. The breather lines from the crankcase need to dump into them to burn up the fumes, or the bike gets really dirty and the stink is unbearable at a light. mine have 90° elbows into the rubber boots. Seems to work pretty well.

Battery is up front because I re-wired the whole bike. I now have trunk space under both seats. Wow, I guess there are still people who haven't seen the 14 cans under the seat pictures. :icon_biggrin:

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Discussion Starter · #6 · (Edited)
Fixed it. I figured if I set the fully closed plates at the exact resistance recommended, then they would open at the right time and it would reduce lag when trying to set the STV's after the error - in doing so, though, the wide open reading was not spot on. I thought this would be okay, given my reading other people's experiences.

Turns out, not really the case... One thing I quickly discovered is putting the potentiometer at the right reading for wide open leaves the fully closed off by a bit, opening a little late I would think? Regardless, having the right setting at wide open seems to make it do the second motion and not have the STA error. I'm thinking it checks the position of wide open and if its not within a certain range (with the closed set properly it was just under 4,000, iirc) it triggers it? Does anyone know what exactly it's doing with the two motions it goes through?

Does anyone know what is inside the secondary throttle valve sensor, creating the resistance based on the amount turned?
 

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The butterfly dance when ignition on is probably to determine the range of motion based on the expected values for min and max resistance at the extremes. It's possible that your sensor is worn out or damage (scored potentiometer) and doesn't consistently indicate the expect values. I would measure the resitance through the whole range and see if there is any jump in value.

About the 2 motion dance vs 1. One simple explanation is that if the first dance fails, it won't perform the second dance. Another is that the linkage is poorly adjusted and restricting the actuator motion. I would try to remove the linkage temporary and see if the start dance returns to normal.
 

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Discussion Starter · #8 ·
So, it is just a arm moving across a resistive strip inside it? If it is, im assuming physical modification to bring the values closer wouldnt be hard...

Thats kind of what I expected it would be doing - it doesnt check fully closed impedance in its two motions, only wide open. Im assuming this is to check compliance, as you suggested? Although Im not sure why it wouldnt check closed, maybe because of assumed cohesion between the two values... Or because the low end doesnt matter as much as the STV eventually becoming fully open during throttle movement, since chances are impedance will eventually meet and pass the .58?
 

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The 'STV Dance' changes with engine temperature. When fully cold, the STV's will go to open which is what activates the Fast Idle. If it's not cold enough...it won't go that far open, but it's been quite a while since I've had working STV's so my memory on them isn't perfect.

Setting the STV sensor works better if you get as close to the desired values on both open and closed as you can rather than hitting one exactly which leaves the other way off. The ECU wants to see the STV motor move and it watches the current draw to make sure the motor is turning, then it watches the sensor limits to make sure they're within specs.

I was never able to get exactly what the manual called for on the sensor, so shot for the middle and they always worked fine. If I pushed the adjustment too far either way...it would get 'FI' lights sometimes...so maybe that's all that is going on with the OP.
 

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The 'STV Dance' changes with engine temperature. When fully cold, the STV's will go to open which is what activates the Fast Idle. If it's not cold enough...it won't go that far open, but it's been quite a while since I've had working STV's so my memory on them isn't perfect.

Setting the STV sensor works better if you get as close to the desired values on both open and closed as you can rather than hitting one exactly which leaves the other way off. The ECU wants to see the STV motor move and it watches the current draw to make sure the motor is turning, then it watches the sensor limits to make sure they're within specs.

I was never able to get exactly what the manual called for on the sensor, so shot for the middle and they always worked fine. If I pushed the adjustment too far either way...it would get 'FI' lights sometimes...so maybe that's all that is going on with the OP.
RecoilRob it hurts my brain trying to follow you guys and learn this stuff. So please bare with me here. But question: my bike was stalling at around half throttle and/or at around 6k-7k rpm
Range. I looked in the gas tank, saw awfully large amounts of rust, assumed problem found. No FI lights or anything showing on the dash. Pulled fuel pump, cleaned the heck out of that. De rusted tank, sealed tank, put fuel pump back in, hooked it all back up and now the bike won’t even start. I spray starter fluid into my air box and she fired right up. So I’m thinking my fuel pump was just already set on failing and I pushed it off the cliff messing with it? But anyway, as I wait for my new fuel pump to get here, I’m combing thru and checking stuff, etc. and I noticed that the top butterfly valve (I think you guys are talking about here), the actuator rod outside the box that has the spring on it, I noticed it just moves very easily, just looking at it wrong and it falls or swings open and doesn’t even snap back without me assisting it closed. Could this be my issue? And my fuel pump is fine? Also noteworthy: I dropped my bike right on that side a month or 3 back… landed right on the handlebar. Broke my mirror off… but throttle works fine. I don’t know. Any advice greatly appreciated. I’m going crazy without my bike! Send help.
 

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That’s a rather old thread to hope for a response from. If you want to test your theory, you can open that top butterfly valve as it tries to start. I’d doubt that’s the case, though. If it fires and tries to run on starter fluid, or gasoline directly poured into the cylinder, it shows a lack of fuel, rather than a lack of air.
 

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Sometimes I get a crank no start condition, and the FI message and red LED is flashing. I cycle the key, and it goes away and the bike starts. Is this my problem?
 

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RecoilRob it hurts my brain trying to follow you guys and learn this stuff. So please bare with me here. But question: my bike was stalling at around half throttle and/or at around 6k-7k rpm
Range. I looked in the gas tank, saw awfully large amounts of rust, assumed problem found. No FI lights or anything showing on the dash. Pulled fuel pump, cleaned the heck out of that. De rusted tank, sealed tank, put fuel pump back in, hooked it all back up and now the bike won’t even start. I spray starter fluid into my air box and she fired right up. So I’m thinking my fuel pump was just already set on failing and I pushed it off the cliff messing with it? But anyway, as I wait for my new fuel pump to get here, I’m combing thru and checking stuff, etc. and I noticed that the top butterfly valve (I think you guys are talking about here), the actuator rod outside the box that has the spring on it, I noticed it just moves very easily, just looking at it wrong and it falls or swings open and doesn’t even snap back without me assisting it closed. Could this be my issue? And my fuel pump is fine? Also noteworthy: I dropped my bike right on that side a month or 3 back… landed right on the handlebar. Broke my mirror off… but throttle works fine. I don’t know. Any advice greatly appreciated. I’m going crazy without my bike! Send help.
The rust in the tank will not only clog the inlet screen on the bottom of the fuel pump....but also the 'High Pressure' filter that's in the main body of the fuel pump module that the pump fits into. That is a tiny little filter and it clogs easily so the best remedy is to bypass it and install an external filter. If you need more motivation...check out the price for the factory filter...about $250 last time I looked!!!

The fuel pump itself rarely fails but can if the filter becomes blocked...so you may as well install the new pump you have coming along with at least flowing the 'High Pressure' filter to make sure it's open. Some people have had success back-washing it carefully and if you're worried about the external filter install...it's worth a try.

The 'top butterfly valve' you mention is the Secondary Throttle Valve and for sure it's not supposed to be swinging free as you describe. Something wrong there as both STV's should be linked together to the motor which then moves them through gearing. You should not be able to move either STV by hand at the valve...only by turning the actuator motor. If your Check engine light isn't on for the STV system...but something is broken in the linkage, I'd just remove the plates and call it a day...it'll run just fine.
 

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Sometimes I get a crank no start condition, and the FI message and red LED is flashing. I cycle the key, and it goes away and the bike starts. Is this my problem?
Not likely. What I'd suggest is to jump the Factory Diagnostic connector and see what code shows up when you get the no start. Don't turn the key off when it happens or the code will be lost...got to check it when the fault is present. Easiest way to do this is to install a switch on the Diagnostic connector so you can easily just flip it to get the code should something happen. Suzuki Dealer Mode Switch FI Error Code Light SFV650 SV650 SV1000 VL800 #K106 H | eBay
 

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Not likely. What I'd suggest is to jump the Factory Diagnostic connector and see what code shows up when you get the no start. Don't turn the key off when it happens or the code will be lost...got to check it when the fault is present. Easiest way to do this is to install a switch on the Diagnostic connector so you can easily just flip it to get the code should something happen. Suzuki Dealer Mode Switch FI Error Code Light SFV650 SV650 SV1000 VL800 #K106 H | eBay
Yeah it usually happens at times when I have to get it started so I can go back home. Thanks for the link, that looks like exactly what I need.
 
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