Mates, need advice of those who know.
I have a problem with fast idle, when engine is cold:
When I start my bike, it starts with higher revs, but instead on 30 sec at 20C°, revs are higher only for 3secs, and then drop to normal, which on a cold engine are less then 1000rmp. At this moment, I manually add revs (by idle revs knob) to ~1200 and as far engine gets hotter and hotter (during riding), revs are going up and up. Up to 1500. At some moment, on a traffic light, I have to lower idle to 1100-1200.
How I understand this situation: there is a problem in my fast idle system.
Do not remember exactly when it happened (long time ago, I just was lazy to deal with it), but probably after I was synchronization throttle valves.
Yesterday I check TP and STP sensors settings (according to service manual 4-35 and 4-43). Voltage on open-close positions of both sensors, was quite perfect. Also STV actuator seems to work, because STV was moving during self test, after ignition was switched on...
Tomorrow, I want perform a FAST IDLE INSPECTION (service manual 4-65)... Does anyone have done this, or have similar experience and can give me some advice what to be prepare with? :confused1:
Any information is apraitited.
The timing of your post is perfect for me. My problem is similar to yours. When starting the idle drops to just below 1000 rpm and slowly (after a minute or a little more) rises to 1100. Ambient temperatures are above 20 degree celsius. Here comes a possible clou. By accident I hit the kill switch just after starting (less than 1000 rpm). When I restarted, the fast idle behaved perfect. RPM goes to 1400 plus and after 30 seconds down to 1100. Since then I have repeated this several times. Always behaves perfect after hitting the kill switch and restarting again.
My TP, STP, and STVA are also working/set up near to perfect. Tomorrow I will do an electronic reset (as I described here in another post). If that doesn't help, I'll inspect the ECU (ECM) contacts. Would be great if someone here has any ideas, experiences, and hopefully a solution (before the cold season kicks in at last)
Would be cool if you try the kill switch thing too. Please report.
I'm skeptical, but I will try kill switch tomorrow. Will let you know.
What is "electronic reset" in case of 14? :confused1:
skeptical is always good!
I'll tell you about about the reset tomorrow (today). Need to get to bed urgently :)
I have my version of the same issue. After cold start she runs 2-3 seconds slowly and stops, and after second start she runs nice 1500 rpm. This is not happening in every start and always under + 8 degrees celsius. Like the "cold idle system does not have enough time to activate". if you give her a little bit throttle during that 2-3 seconds slow run, she keeps on running 1500 rpm.
I have the same issue, when ambient temps are under 20C it will stall. I always let it run for 2 minutes after staring before riding, so it doesn't cause me any problems.
<thinking>
I had this years ago & fixed it without changing any parts, trying to remember how.
Quote from: northern on Friday, 21 July 2017, 05:38 AM
I'm skeptical, but I will try kill switch tomorrow. Will let you know.
What is "electronic reset" in case of 14? :confused1:
The electronic reset did not solve the problem, but here is how you do it anyways:
disconnect the ground cable from the battery
turn on the ignition (don't start engine) so the capacitors in the system discharge fully, ECU's temporary memory (where it stores adjustments) gets cleared as well. Leave it like that for 5 minutes.
turn ignition off
reconnect ground cable of the battery
turn ignition on
fully open and fully close the throttle, repeat
without touching the throttle, start the engine and let it idle a couple minutes
take a ride
So, seems I solve this issue, but I'm not happy, cause I have new issue... :frustrated:
According to service manual, while ignition is on:
"...Open the secondary throttle valve fully by turning its link with the finger. With the secondary throttle valve held at this position, easure the output voltage of TP sensor...
... TP sensor output voltage: 1.195 V..."
I use pins, to connect circuit tester to TP and STP sensors wiring, and ajast TP sensor voltage by turining bolt marked with red arrow until TP sensor voltage was 1.195v, while I manually, through the air box, completely open Second throttle valve.
When I put all parts together, and finally manage to start engine, fast idle was much more like it should be.
But, I discover new issue, which kill my day - battery is not charging, and I can't start bike by itself :thumbs_down:. But this is other topic...
Interestingly on a Gen-1 Hayabusa, a similar size / age / injected / Suzuki, the fast idle is mounted on the bars and looks like an Old Skool choke lever. The little lever controls the revs on a cold motor, looks (and feels a little) just like a choke on some of my past bikes but its just a crude and effective way to raise the revs. A thing of the past now I guess.
Today I can confirm, what "fast idle" is OK now. After the start, it was ~1700rpm for half a minute, and then start slowly drop revs until normal.
So if you have issues with your's bike fast idle:
- Check and ajust TP sensor voltage open and close
- Check and ajust STP sensor voltage open and close
- Check and ajust TP sensor voltage, while Secondary Throttle valve is fully opened. It should be 1.195V (mine was ~1.12V). If it's not OK, calibrate it using adjusting bolt (my previous post)
Done.
Hope it will help someone in future :hat:
Nice one, took me months to solve mine when it did it. I think I solved by just adjusting both TPS, so the same thing as you really.
I'm also having a fast idle problem . As in it doesn't work at all . Starting from cold can take a few attempts .
I'm not sure exactly how the fast idle works and if in fact it's totally electrical or there is some sort of mechanical part as well . However I've got the tank off at the moment to synch the throttle bodies and found this (see pic). This is in the centre of the injectors and is not controlled by anything . It moves around by touch and the little wheel is not in any sort of track . The L shaped bracket does look a little bent . Any clue please ?
Go to the downloads and get the Manuel and read through before you do work on the bike your not sure about as a first thing.
All info you need on this in section 4-62 onwards of the Manuel.
For balancing the throttle bodies I think 1 (2 or 3)is set(like with carbs)
The outside pair's are adjusted from above but to sync the 2 halves the adjuster is underneath a bit if a pain to get to but that's where they are located.
You should probably check the tos and stps and throttle cable adjustnent before syncing the throttle bodies as all this should help your cold starting .
The warming up higher revs is controlled by the ecu but the things listed above affect the readings used by the ecu.
Hope that helps
:cheers:
Thank You Seth.
I'lll have a read of the ifo in the downloads before i start attacking things with a screwdriver... The bike has been subject to a previous enthusiastic amateur mechanic who's fiddled with pretty much everything.
I had the bike on the dyno at John Warringtons and he confirmed that at idle the lh two throttle bodies were 'doing nothin'.
I've got some vac gauges and although i've used them several times on carbs this will be the first time on injection. I guess the principle is almost the same tho.
Indeed it the same if you can do carbs you'll be fine.
Sounds like the throttle bodies have been over adjusted(and are set to high) so bringing them all down should bring the fast idle adjust back into use.
Take your time and you'll be ok
Good luck buddy :cheers:
#1 in the attached pic is for syncing 1/2 with 3/4.
#2 is for fast idle. Don't touch this until after you have done everything else (see above posts of Seth and Northern). I would start with cleaning all the connectors first with contact cleaner. EDIT: just read the last posts. Synching might be all you need to do.
Here you can see what makes the "little wheel" move: https://www.youtube.com/watch?v=AhMkXCFyv6I&feature=youtu.be
Great info
@Andre This should be made a sticky or something(
@gsxbarmy @VladTepes ) as its so very useful to know where the adjusters are(I've never adjusted mine so wasn't totally sure).
We'll found buddy hope this helps
@Simonic :cheers:
Many Thanks to you both Seth and Andre.
The video was especially interesting.
The little wheel is in fact in line with the operating cam so this would suggest the the trottle bodies are indeed over adjusted on the offside bank.
I'll report back when i've had done the synchro.
Thank You again gentlemen
BTW, my fast idle problem was solved after I re-re-cleaned connectors. First cleans were done with WD40, last one with contact cleaner :stir:
Quote from: seth on Saturday, 18 May 2019, 10:46 PM
Great info @Andre
This should be made a sticky or something( @gsxbarmy @VladTepes ) as its so very useful to know where the adjusters are(I've never adjusted mine so wasn't totally sure).
We'll found buddy hope this helps @Simonic
:cheers:
@seth - this thread has been a sticky for a long time already.....no need to re-sticky it :onya:
@VladTepes
@gsxbarmy Sorry i ment just the picture of the adjusters I know this is a sticky thread.
It will save time when folk come asking for this very thing .
Thanks for the reply buddy .
:onya:
@seth I put in a couple pics in Fuelling / Re: Synchronize your Throttle Valves. I think they belong there.
http://gsx1400owners.org/forum/index.php?topic=262.msg55089#msg55089 (http://gsx1400owners.org/forum/index.php?topic=262.msg55089#msg55089)
Cheers buddy between what
@gsxbarmy had already done and your added pictures there is everything in one place .
Top job :onya:
Reporting back....
I've managed to synch the throttle bodies ok.
The rhs was doing al the work and in addition to that the difference between 1+2 was huge. it really looks like someone had just been trying to make some adjustments without knowing what they were doing.
The bike is running much better now.
The fast idle still is not working but i can get the bike started ok.
This is a job foar another day.
I'd like to thank all you guys who have offered advice. Much appreciated :cheers: :cheers:
Quote from: Simonic on Sunday, 02 June 2019, 08:17 PM
Reporting back....
I've managed to synch the throttle bodies ok.
The rhs was doing al the work and in addition to that the difference between 1+2 was huge. it really looks like someone had just been trying to make some adjustments without knowing what they were doing.
The bike is running much better now.
The fast idle still is not working but i can get the bike started ok.
This is a job foar another day.
I'd like to thank all you guys who have offered advice. Much appreciated :cheers: :cheers:
I know this is an old thread, but did you get the fast idle sorted out? I have a mate that has the same problem, TPS and STPS are just about spot on, but when measuring the voltage as mentioned in another post, adjusting the fast idle screw makes no change to the voltage, the resistance of STVS is correct as are all other sensors...bit of a strange one, bike runs and pulls really well apart from this.
Quote from: T250 on Monday, 25 May 2020, 06:30 PM
Quote from: Simonic on Sunday, 02 June 2019, 08:17 PM
Reporting back....
I've managed to synch the throttle bodies ok.
The rhs was doing al the work and in addition to that the difference between 1+2 was huge. it really looks like someone had just been trying to make some adjustments without knowing what they were doing.
The bike is running much better now.
The fast idle still is not working but i can get the bike started ok.
This is a job foar another day.
I'd like to thank all you guys who have offered advice. Much appreciated :cheers: :cheers:
I know this is an old thread, but did you get the fast idle sorted out? I have a mate that has the same problem, TPS and STPS are just about spot on, but when measuring the voltage as mentioned in another post, adjusting the fast idle screw makes no change to the voltage, the resistance of STVS is correct as are all other sensors...bit of a strange one, bike runs and pulls really well apart from this.
Might be worth checking if the cam wheel is actualy on the cam... found mine was not seated on the fast idle cam.
You can have all the correct measurements on all sensors but if there is nothing to engage the high idle to... well... you feel kinda stupid when you remove your old throttle bodies to replace them with a new bank :doh:
Might be worth checking if the cam wheel is actualy on the cam... found mine was not seated on the fast idle cam.
You can have all the correct measurements on all sensors but if there is nothing to engage the high idle to... well... you feel kinda stupid when you remove your old throttle bodies to replace them with a new bank :doh:
Checked the roller was seated all okay, just starting to wonder if the throttle adjustment is way off and contributing to this problem. Going to get the bike over to my place and have a check through, at least I'll be able to compare it to mine ;)
Hi guys. I have a very stupid question. Where is the secondary throttle valve and how can open or close it by a finger?
Download the manual from here, it's all explained there. You can actuate by hand from the linkages under the throttle bodies. The primary you reach from inside the airbox
I did everything as expected. I adjusted the STP resistance - 0.8Kohm on fully closed secondary throttle.
On a warm engine with agusted rpm to ~1100, I adjust the resistance of the TP to 1.1Kohm.
Then I tried to set up the fast idle but max voltage that I get is 1.15V with fully open secondary throttle valve. What I do wrong?
having looked at the excellent instructions on voltage and the screw I have tried a few times to get this sorted now. On the second attempt, I wound the adjustment screw out so much that it came loose! this has led me to the following conclusion... (wish I has taken pictures) between the adjustment screw and 'metal plates' of the throttle bodies there is a small spring. It seems the issue is that the small spring over time looses its 'spring rate' and therefore, even if you allow the metal plates to separate by adjusting the screw, the spring no longer lifts the throttle plate with the force it requires. Its going to be quite fiddly to get it in place. However I will see what I can find although it may now be later in the year as I want to get out riding will the weather is starting to improve.
Looking at the suzuki parts it seems to be item 15 on this microfiche. which is called a Torsion Spring
I had a problem with the springs doing the same job on each TB being too weak once, but only because I'd lost them & replaced them with the wrong ones that were too weak.
What I have had there is the arm the screw presses against seizes on it's pivot & the return spring it's got can't keep it against the end of the adjustment screw. It's a right faff to strip the TBs down just to pop that off & regrease it, but it fixed the issue for me.
So I did some research on TPSes setting and have some material (and problem) to discuss.
I set TPS for 1.153v closed (it's 1.278 - 4.43Ohm TPS range), right after ignition turns on STVA moves throttle blades so voltage on TPS rises up to 1.203v (for cold start). Fully open secondary throttle gives 1.242v on TPS. I know it's not very correct values (I want my bike to be a bit more throttle responsive), but nevertheless I got fast idle from 2100rpm for 30 seconds.
But after fast idle ends engine idles on 1000rpm and want to die. If I hit the killswitch and then try to start again, there will be struggle for it. Eventually engine starts but on 500rpm or so, then slowly rises to 1100. Same problem persist with hot engine, but not so prominent.
(I tried all of this with right TPS values after wiping ECU memory - same story).
Sooo... what it wants and what I'm doing wrong?
Quote from: BaNZ on Tuesday, 14 October 2025, 08:51 AMBut after fast idle ends engine idles on 1000rpm and want to die
At that point I would increase idle speed to 1100. Let it run for a couple minutes, turn off and let it sit to cool completely and observe on next start.
Another point, I'd go with standard settings as a base.
As Andre says std settings. The lower 1.1V /1100ohm is more important than the top settings. Takes a bit but you can get it bang on or just over, say 1.12 1.14v.
Another issue with the STVA is the little magnet inside can break, causing issues. A good check is to watch the StVA actuate as yoy turn the ignition on, it should cycle through its range of motion. If it doesn't, or is jerky, could be the magnet or the mechanism needs a bit of lubricant.
Use the correct settings, setting it wrong just makes it run worse. You won't get more throttle response that way.
Agree with above, not sure how or why you thought better throttle response? Turn it faster/harder, youll get response :laugh:
I see your point, guys.
As for TPS adjustment, the idea to fool ECU with main throttle blades angle, so it will inject more fuel for same amount of air.
Quote from: BaNZ on Wednesday, 15 October 2025, 02:20 AMAs for TPS adjustment, the idea to fool ECU with main throttle blades angle, so it will inject more fuel for same amount of air.
So it'd just run too rich...
More fuel doesn't equal more power unless it's running too lean & these don't tend to do that.
Can of worms this in my opinion & from my own past experience. Once the fast idle screw has been altered it throws all other settings out, trying to get back to standard took a lot of time consuming trial & error adjusting, checking, running allowing to cool and testing again. Before I altered the fast idle screw I marked its position & counted the number of threads on the screw that were visible from the underside, I could then return to the original starting point, every time I did go back to original I found I was getting different readings which seemed strange
Hm... Okay then.
Well... Could someone explain meaning of this text from manual? (Section 4-65 fast idle adjustment).
Not a clue, I couldn't make sense of that bit either. Hence I did mine by trial & error.
If they had just broke it down a bit more, it would have read better. My take on interpreting this procedure is:
1) Set the TP sensor to the correct voltage, write this down.
2) Once you've set that, open the secondary throttle valve slowly until the STP sensor voltage is reading 3.6v.
3) Hold (somehow?) the secondary throttle valve at that exact position where it reads 3.6v.
4) Whilst the secondary is held in the above position, check the TPS voltage output. You're looking for a variation of 0.035v from step 1. when the STP sensor has a reading of 3.6v.
5) If the TPS is not showing 0.035v difference, adjust it by turning the Fast Idle Screw to get the desired result of 0.035v.
That's how I read it too Col. Issue is 0.035V is so small that just moving the connector slightly would see a change larger than that, and adjusting the TPS by that minuscule amount is yet another challenge. Just by tightening the security torx on the sensor you get 0.1 to 0.2v differences.
It's as Hooli says, hit & miss.
I reckon a magician required to see.03v. BAnz, my advice, set your tps at 1100ohms or close closed, set your idle speed 1100rpm.over time from cold, adjust cold start idle until acceptable to you.She should be ok then just leave it alone, set and forget.If you really want/need quicker reaction off the line, fit atre and R1 Yamaha throttle tube, thatll do it👍