Hi all
So I have had my bike in with Motrac Race Engineering this last week and have had a custom map done, the difference is noticeable from idle all the way through to the top end, power delivery is smooth all the way and my rough idle has been cured, she was far to lean at idle which has been sorted and the results are 108hp with my standard set up other than twin Beowulf end cans, which is not too bad
My question is, my fast idle is not currently working despite everything being in spec, will this be due to the rise in ambient temperature at the moment? It was 18 degrees here at 9am this morning and the bike lives in a garage which again is pretty warm at the moment
I don't want to start tinkering again if this is normal so any views would be appreciated
Thanks
Pete.
I wouldn't worry about it too much just yet if the bike starts good.
At the moment my fast idle is barely a fast idle and then it only lasts around 10 seconds max from cold..
I am assuming its due to the warmer weather now..
S.
Quote from: Speedy1959 on Sunday, 11 June 2023, 02:38 AMAt the moment my fast idle is barely a fast idle and then it only lasts around 10 seconds max from cold..
I am assuming its due to the warmer weather now..
S.
Yep, that's what is does on the upsidedown part of the world too, now it's a bit cooler it runs for about 15 sec before it's back to 1100. I wouldn't worry about it Pete, the bike has been tuned & sorted, so leave it be would be my recommendation.
They could have adjusted the start up fueling so there's no need to have the fast idle come in?
Thanks for the replies much appreciated
I'm sure that it will work once the temperatures get back to normal, if there is a normal any longer! It's just one of those that I would like to know if it is working or not, there must be a way of fooling the ECU to test it, but will think about that again
The fueling has definitely been adjusted at idle, looking at the map file adjustments it seems the bike was quite lean low down but quite rich at higher revs, starts first push of the button and runs at approx 1000 rpm then takes approx 30/60 seconds for the revs to get up between 1100 & 1200 rpm
Thanks again
Pete
Will, works for 30 secs at my current around 12 temps, Summer never does. All good Mate.
Quote from: grog on Sunday, 11 June 2023, 06:38 PMWill, works for 30 secs at my current around 12 temps, Summer never does. All good Mate.
Thanks Grog, that's pretty reassuring all should be good :onya:
all bikes are set up as lean as possible from the factory so they need choke (fast idle) richer mixture to start, but yours as had the mixture richened up so won't need it like a standard 1400.
From memory of reading the workshop manual the fast idle is a two stage process. 30 secs of increased revs and two mins slightly increased. There's a couple of trigger points based on temp which I can't recall.
Mine does much the same as yours, which is good as I've had to setup the fast idle stuff recently after having the TBs totally in bits.
Quote from: KiwiCol on Sunday, 11 June 2023, 06:24 AMQuote from: Speedy1959 on Sunday, 11 June 2023, 02:38 AMAt the moment my fast idle is barely a fast idle and then it only lasts around 10 seconds max from cold..
I am assuming its due to the warmer weather now..
S.
Yep, that's what is does on the upsidedown part of the world too, now it's a bit cooler it runs for about 15 sec before it's back to 1100. I wouldn't worry about it Pete, the bike has been tuned & sorted, so leave it be would be my recommendation.
They could have adjusted the start up fueling so there's no need to have the fast idle come in?
@KiwiCol you are spot on there. I had the PC disconnected yesterday while I was tinkering & started the bike, the cold start kicked in straight away, reconnected the PC and tried again much later in the evening and no cold start
I have now made a copy of the custom map and reduced the fuel changes at 500 to 1500rpm only at throttle position zero and this evening the cold start kicked in with the custom map, I only changed the fuel to the standard zero setting at these increments
This got me thinking, if I was to change the same settings to minus numbers at throttle position zero from 500 to 1500 rpm would this fool the cold start into kicking in when the bike was warm? I was originally under the impression that the cold start only worked inline with the ambient temperature, but not so sure now?
Pete
Cold start is mostly based on the oil temp rather than ambient temp.
Quote from: Hooli on Tuesday, 18 July 2023, 07:30 AMCold start is mostly based on the oil temp rather than ambient temp.
@Hooli thanks, Ah right I see, do you know how and where the oil temp is measured & I'm guessing that the ECU must be preventing the cold start from functioning with the richer mixture in the custom map then?
I'm still trying all sorts to find the cause of the bad running issue I have, even after getting the custom map done I still have a bit of a running issue. I can replicate it now and it always happens at 60mph in 5th & 6th gear at a tad under 3000rpm - crack the throttle wide open and the bike stutters for a few seconds then pulls like hell again, not a nice feeling mid bend or when going for an overtake! I have pulled most of my hair out trying to cure this, almost at the point now where I am about to give up and get rid, last week I had decided enough was enough but had another think and have decided to give it one last push to try and fix before selling :frustrated:
The oil temp sensor is behind the barrels, just by that Y shaped oil pipe. It's got black and black/white wires from memory. The wiring goes up the side of the airbox to a plug next to the frame tube.
Mine failed without causing a code, but it was giving a resistance about 10x higher than it should so my bike was mega rich. There's values in the workshop manual to test against.
I assume you've tried unplugging the clutch switch when the bike is running? I've seen the springs in the fail so the bike stays on the starting map. When that happened to me mine would cough before it went if given a handful.
Reckon Hooli might have a good idea, clutch switch.Easy to check, sit with bike in 1st gear, as you slightly pull in or let clutch lever out slowly, you can hear/tell different mode kick in, at least can on mine.
Quote from: Hooli on Tuesday, 18 July 2023, 06:02 PMThe oil temp sensor is behind the barrels, just by that Y shaped oil pipe. It's got black and black/white wires from memory. The wiring goes up the side of the airbox to a plug next to the frame tube.
Mine failed without causing a code, but it was giving a resistance about 10x higher than it should so my bike was mega rich. There's values in the workshop manual to test against.
I assume you've tried unplugging the clutch switch when the bike is running? I've seen the springs in the fail so the bike stays on the starting map. When that happened to me mine would cough before it went if given a handful.
@Hooli thanks again for the information, I fitted a new clutch switch last year - supposedly a genuine Suzuki item. I did have a look at it a bit closer this evening and one of the wires going into the spade connector didn't look the best so chopped them both off and fitted new terminals, just to tick that box
One thing I have noticed, with the ignition on but the bike not running if I pull the clutch lever in, then let it out there is a small sound from the pump in the tank as if its getting a signal, I presume that this is the way it should be :confused1:
I will try and get the oil temp switch out tomorrow & test to see what readings I get, possibly easier said than done, looking at its position it may me fiddly with my shovel sized hands :undecided:
Quote from: grog on Tuesday, 18 July 2023, 06:22 PMReckon Hooli might have a good idea, clutch switch.Easy to check, sit with bike in 1st gear, as you slightly pull in or let clutch lever out slowly, you can hear/tell different mode kick in, at least can on mine.
Thanks @grog i'm presuming that you mean with the bike running from cold?
No need to remove it, just measure the resistance at the connector up by the airbox.
I'm pretty sure there's a measurement for 20c in the workshop manual so that's close to know if it's giving a reasonable figure.
Quote from: Hooli on Wednesday, 19 July 2023, 06:52 AMNo need to remove it, just measure the resistance at the connector up by the airbox.
I'm pretty sure there's a measurement for 20c in the workshop manual so that's close to know if it's giving a reasonable figure.
Have just been reading the manual, there are a set of resistance readings from 20c up to 110c so will do as you suggest and take it from there, The thing is peeing me right off at the moment, worse of all I can ride around the problem by dropping a gear or two on hard acceleration but I see that as avoiding the issue and will always have it in my head that its not quite right :thumbs_down:
Thanks again for your input, much appreciated
Will, warmed up, just play with clutch lever, i can tell mine changes tune.
and mine.
When you're sitting at the lights waiting, (or in your driveway) with the clutch in (engine running of course) just let the clutch out a wee bit at a time, no revs, & you'll hear and see the revs increase as it changes maps, ready to ride off. Been ages since I even took notice of it, but reckon it's probably only 200 - 300rpm increase, but it's noticeable.
My Black & my Blue both do it, so it's not colour dependant. :stir: :whistling:
Pull the plug off clutch switch and have a ride, difference is amazing on mine. I once did as experiment.
So tonight's adventures, tested the resistance of the oil temp sensor, 63K Ohms with the engine cold, ran the bike for 10 mins and measured the resistance again and it was 17K Ohms so that seems to be OK
While I had the LHS panel off I cleaned the contacts on the remainder of the plugs that side, I then removed the headlight as there was a bit of a vibration rattle from something in there, found nothing obvious but while I was in there opened each plug and gave a decent dose of contact cleaner, all but one plug were like new, a minor bit of corrosion on the one but not enough to create any issues
Started the bike and no change to the running (as expected really) other than after idling for a minute or so she cut out and stopped altogether, no FI light showing and restarted straight away, maybe me being over liberal with the contact cleaner is what I have put that one down to
So that's me running out of things to check and change, maybe take the injectors out tomorrow and get them tested/cleaned but did that a couple of years ago so not holding up too much hope with that
I also seem to have adopted a horrible metalic rattle at 2000rpm now, just to add more fuel to the fire! Sounds like top RHS of the engine but hard to pin point it, could be clutch area. Tried adjusting the idle to 2K revs so I could do some listening and finding but it stops after a few seconds so have to keep throttle on and off which I'm sure was pissing the neighbors off as much as me!
I think the time is fast approaching to throw her in against something else, this really annoys me as I love the bike & I seem to have grown a conscience and wouldn't want someone else to buy the bike and adopt the problems
Pete...
Well I have removed the injectors and had them tested, cleaned and retested all OK, refitted them this afternoon and no change to the poor running
I have bought a set of used throttle bodies off ebay & was going to start removing the original ones this afternoon to fit them, but had a bit of a brainwave to compare the new set with the original set, low and behold the fast idle or cold start screw on the original set had been fully wound in, so although very crude I know but I counted the number of threads exposed on the new set and replicated this with the original set, started the bike & the cold start kicked in straight away, the revs then settled after 15/20 seconds and the bike appears to be idling much smoother than it ever has in my 5 years of owning the bike, will take it for a run tomorrow evening to see if this has cured the hesitation (had had a few beers by this time)
I may be on the correct path now at long last, although I am a bit skeptical as I tested the voltage for the cold start a couple of weeks ago and it was bang on, although turning the adjustment screw a full rotation in both directions had no effect which was a bit strange
Here's hoping the fault is fixed, at the turn of a screw in the end! :doh:
Will, what happened to your metallic rattle noise?
Good job, so you've now got a set of throttle bodies for sale. :whistling:
Quote from: grog on Monday, 07 August 2023, 07:37 AMWill, what happened to your metallic rattle noise?
Still there at around 2000rpm and seems to disappear when the engine is warm, so thinking possibly valve clearances need checking again although they were OK when I checked last year or even cam chain rattle but not slack enough for the adjuster to move up a notch?
I started the bike from cold when I got home from work this evening, the cold start kicked in but the revs went up to 2500 rpm when first started then dropped to approx 1700 rpm, so wound the fast idle screw in half a turn & will see what happens tomorrow evening when starting from cold
I am just glad that this seems to be having some affect as nothing else that I have tried has made any difference, to the point where I think she will be staying now so has been cleaned and polished and brought back to her shiny best! :grin:
Pete
Quote from: Mick_J on Monday, 07 August 2023, 08:06 PMGood job, so you've now got a set of throttle bodies for sale. :whistling:
Not just yet Mick but possibly in a while to try and recoup some of the money I have paid out trying to get her sorted!
Pete
Quote from: Will14 on Tuesday, 08 August 2023, 05:23 AMor even cam chain rattle but not slack enough for the adjuster to move up a notch?
Adjuster contains a spring which may have lost its springiness over the years.
Quote from: Will14 on Monday, 07 August 2023, 06:49 AMWell I have removed the injectors and had them tested, cleaned and retested all OK, refitted them this afternoon and no change to the poor running
I have bought a set of used throttle bodies off ebay & was going to start removing the original ones this afternoon to fit them, but had a bit of a brainwave to compare the new set with the original set, low and behold the fast idle or cold start screw on the original set had been fully wound in, so although very crude I know but I counted the number of threads exposed on the new set and replicated this with the original set, started the bike & the cold start kicked in straight away, the revs then settled after 15/20 seconds and the bike appears to be idling much smoother than it ever has in my 5 years of owning the bike, will take it for a run tomorrow evening to see if this has cured the hesitation (had had a few beers by this time)
I may be on the correct path now at long last, although I am a bit skeptical as I tested the voltage for the cold start a couple of weeks ago and it was bang on, although turning the adjustment screw a full rotation in both directions had no effect which was a bit strange
Here's hoping the fault is fixed, at the turn of a screw in the end! :doh:
Hey Will!
Thanks so much for sharing your learnings on this issue, I am being faced with the same shit tbh... Would you mind sharing which exact screw, if any pictures or something, did you adjust to get the fast idle to kick in?
Much appreciated mate!
With the tank off, look down in the middle of the throttle bodies. It's just behind the STVA, you'll see what it does when you see it.
I think it's no10 here, but it's been a few years since I did mine.
https://www.suzukiparts.co.uk/shop/online-store/suzuki-parts-finder/gsx/gsx1400/k2-k3-k4-k5-k6-k7-2002-2007.htm?vehicle_id=29#!gsx1400throttlebodyk2
Thanks mate.
What was the reason you adjusted yours? I read in the forum that adjust the screw causes more problems than brings solutions.
Ok, just checked on the main fuel injectors output plug (big grey one with multiple pins), where according to YouTube, I've tested the resistance of the TPS there. It was off by 100Ω (what I've previously adjusted already on the main sensor output plug (3 pin).
I've adjusted it to 1130kΩ now.
However, when in full throttle, the resistance wouldn't fo higher than 2.5kΩ in contrast with the TPS output plug which would show 4.5kΩ of sorts.
Please let me know if I fucked things up or not. It's quite late in Poland, so I couldn't start the bike. However, I primed the ignition switch a couple of times and I can confirm that I did hear the servo operating the secondary throttle valves. I don't know if they opened or closed fully, but I could definitely hear the mechanism work.
That's all for now folks, awaiting your precious input!
Quote from: imweirdimnotsocial21 on Monday, 16 March 2026, 06:12 AMThanks mate.
What was the reason you adjusted yours? I read in the forum that adjust the screw causes more problems than brings solutions.
Because I'd stripped the TBs totally apart & took that bit apart to fix a fault & had forget to measure where it was set first. From memory the screw opens a 'V' that sits the backside* of the STVA and the throttle shaft, the whole thing had seized on it's pivot on mine so I took it apart to clean & regrease it. The stickiness was making the fast idle stay on constantly.
*backside as the STVA turns backwards to do the fast idle control
As to the readings you're getting, not many people see anything like the high reading in the manual. As long as the idle setting is about right you're good. The resistance is only a basic setting to get the bike close, what really matters is the return voltage as that's what the ECU uses to calculate the STVA position for the fast idle.
Have you checked the STS too? as the ECU uses both to understand the STVA position as there's no feedback from the STVA directly. Hence when my SPS failed I was getting a C28 STVA fault code, when the real issue was C29 SPS.
Getting that fast idle working again is a pain in the arse as it only occurs for 15-30secs on a cold start, with up to 2mins of less rev increase. Plus it's all controlled by oil temp so you can't fiddle & retest more than once or twice. I lost count of the amount of times I lifted the tank to turn that screw 1/8-1/4 of a turn to get it just right.
Woah mate, that must've been a pain. Thanks again for sharing the details.
I mean, I'd try not to touch the screw for now... Other than that, could you help me understand what STS and STVA and SPS mean? I am only aware of the TPS and the STPS.
I'll try to check voltages next time around I guess. Before doing unplugging everything again, I'll also try to check on the mechanism and the "V" valve you mentioned, and see if it is seized or not.
As I am not keen on taking the TBs out, where should I look for that V? RHS or LHS? From what I remember, I couldn't see clearly of a "V" shaped valve/actuator...
God damnit, this is such a painful work... I am really surprised so many people struggle with this. Ah! To mention, I also put the bike in Dealer mode and checked if post my last TPS adjustment on the 13pin injector output plug, the screen shows that it is right bang on in the middle.
If dealer mode shows the TPS is ok then that's good enough as it's the ECU reporting that from the voltages fed back to it.
Sorry about the abbreviations, I just assume people know them as I've fiddled with these bikes for so long.
TPS - Throttle position sensor, on the LH side of the bike as you know.
SPS - Secondary throttle position sensor, looks the same as the TPS but on the RH side. It's a different colour plug (white?) where it joins the FI loom on the throttle bodies.
STVA - Secondary throttle valve actuator. In the centre of the throttle bodies there's a square body that looks like it's made up of lots of plates from above. This is the motor that controls the secondary throttles & also turns backwards to activate the fast idle. That's the bit you hear move when you turn the key on.
The V-shaped bit isn't easy to see with the TBs fitted to the bike. It pivots off the bracket for the throttle cables with the V facing backwards. One side of the V sits against the cam on the STVA, the other forms the idle stop against the throttle spindles (next to the idle control cable). So when the STVA pushes on it, the idle is increased. The fast idle screw goes between the open ends of the V & moves them less or further apart, hence affects the fast idle speed.
I think I've put pics on here years ago, but it's probably lost in the general threads. If I find the pics tonight I'll post a few here for you as it's a lot easier to see than explain.
That's good enough mate.
Thanks again.
I'll report on all the fast idle posts I'll find in case what I did fixed mine lol
Good luck with it.
I had a look around & found the pic I was thinking of. This is No2 TB looking from the RH side as I'd split them apart. Normally this view is blocked by No3 TB.
Marked at the top is the fast idle screw, you can see the V shaped bit it goes into & the pivot to the right that'd seized on mine. The roller below the screw moves the secondary throttle shaft to open them as needed. The red blob is roughly where the part on the shaft would sit.
The roller to the right marked with another arrow is the fast idle control, as you can see if it moves to the left in the pic it'll rotate the throttle shaft so it moves away from the idle stop at the bottom and increase the engine speed. As I recall this roller is attached to the same plate the screw is in, so enlarging the angle in the V increases the fast idle speed.
14 STVA (800 x 969).jpg
Hopefully it's easier to visualise what happens now.
You're a champ mate! Thanks for sharing!!!!!
Quote from: Hooli on Monday, 16 March 2026, 06:00 AMWith the tank off, look down in the middle of the throttle bodies. It's just behind the STVA, you'll see what it does when you see it.
I think it's no10 here, but it's been a few years since I did mine.
https://www.suzukiparts.co.uk/shop/online-store/suzuki-parts-finder/gsx/gsx1400/k2-k3-k4-k5-k6-k7-2002-2007.htm?vehicle_id=29#!gsx1400throttlebodyk2
Thanks Hooli
@imweirdimnotsocial21 All I would say is before altering the fast idle screw make sure the TPS & STPS are set correct first, there is a guide on the site, 9 times out of 10 this can be the fault and is much easier to set than the fast idle adjustment which in my case and some others I think came down to many nights trial & error getting it set correct, regardless of voltage readings
Quote from: Will14 on Wednesday, 18 March 2026, 07:29 AMQuote from: Hooli on Monday, 16 March 2026, 06:00 AMWith the tank off, look down in the middle of the throttle bodies. It's just behind the STVA, you'll see what it does when you see it.
I think it's no10 here, but it's been a few years since I did mine.
https://www.suzukiparts.co.uk/shop/online-store/suzuki-parts-finder/gsx/gsx1400/k2-k3-k4-k5-k6-k7-2002-2007.htm?vehicle_id=29#!gsx1400throttlebodyk2
Thanks Hooli
@imweirdimnotsocial21 All I would say is before altering the fast idle screw make sure the TPS & STPS are set correct first, there is a guide on the site, 9 times out of 10 this can be the fault and is much easier to set than the fast idle adjustment which in my case and some others I think came down to many nights trial & error getting it set correct, regardless of voltage readings
Awesome mate, my TB adjustment is also overdue, so I'll try to adjust the TBs on the weekend and when I'm done, I'll start adjusting the TPS and STPS sensors while reading their voltage inputs and outputs this time instead of the kΩ resistances.
If I remember rightly, both sensors get 5v in. I've found it easier to set on Ohms, but mV works as well. TPS should be as close to 1100ohm as possible at 1100rpm and a warm engine, blip the throttle and let it close by itself.
STPs 3500ohm when closed from memory.
Quote from: Eric GSX1400K3 on Wednesday, 18 March 2026, 10:42 PMIf I remember rightly, both sensors get 5v in. I've found it easier to set on Ohms, but mV works as well. TPS should be as close to 1100ohm as possible at 1100rpm and a warm engine, blip the throttle and let it close by itself.
STPs 3500ohm when closed from memory.
Yeap, would you recommend the TPS sensor itself measures to be set at 1100Ω or the injector outpost (13pin I belive) connecting to the ECU, measured at 1100Ω?
I understand I can only check STP at the plug itself, so I'll fix that that way.
Quote from: imweirdimnotsocial21 on Wednesday, 18 March 2026, 11:26 PMQuote from: Eric GSX1400K3 on Wednesday, 18 March 2026, 10:42 PMIf I remember rightly, both sensors get 5v in. I've found it easier to set on Ohms, but mV works as well. TPS should be as close to 1100ohm as possible at 1100rpm and a warm engine, blip the throttle and let it close by itself.
STPs 3500ohm when closed from memory.
Yeap, would you recommend the TPS sensor itself measures to be set at 1100Ω or the injector outpost (13pin I belive) connecting to the ECU, measured at 1100Ω?
I understand I can only check STP at the plug itself, so I'll fix that that way.
I find it easier to measure both sensors at the big grey plug behind the panel on the left hand side, also easy enough to close the secondaries with the linkage under the throttle bodies rather than removing the air filter. I have in the past also compared readings from the big grey plug & at each sensors plugs, both differed by about 50ohms, so I compensate for this when setting to 1150 & 850ohms at the grey plug for me seems to work just fine
Another way of checking the TPS is to put the bike in dealer mode, a small dash comes up on the bottom of the speedo which is showing the TPS setting, if dash is in the centre it is fine, over to the left or right adjusment is required
Quote from: Will14 on Thursday, 19 March 2026, 04:36 AMQuote from: imweirdimnotsocial21 on Wednesday, 18 March 2026, 11:26 PMQuote from: Eric GSX1400K3 on Wednesday, 18 March 2026, 10:42 PMIf I remember rightly, both sensors get 5v in. I've found it easier to set on Ohms, but mV works as well. TPS should be as close to 1100ohm as possible at 1100rpm and a warm engine, blip the throttle and let it close by itself.
STPs 3500ohm when closed from memory.
Gotcha mate!
Thanks for that! :)
On the youtubes, I found how to measure the TPS, which pins to connect etc.
Which ones would be for the STPS? And how do you move the flaps without removing the air filter?!
(I can also indeed put the bike into dealer mode and adjust as such, easier).
Thanks for the continuous support!
Yeap, would you recommend the TPS sensor itself measures to be set at 1100Ω or the injector outpost (13pin I belive) connecting to the ECU, measured at 1100Ω?
I understand I can only check STP at the plug itself, so I'll fix that that way.
I find it easier to measure both sensors at the big grey plug behind the panel on the left hand side, also easy enough to close the secondaries with the linkage under the throttle bodies rather than removing the air filter. I have in the past also compared readings from the big grey plug & at each sensors plugs, both differed by about 50ohms, so I compensate for this when setting to 1150 & 850ohms at the grey plug for me seems to work just fine
Another way of checking the TPS is to put the bike in dealer mode, a small dash comes up on the bottom of the speedo which is showing the TPS setting, if dash is in the centre it is fine, over to the left or right adjusment is required
I've done both, at the big grey plug and at the sensor plug. I prefer the sensor plug, i can get to within 2ohm or so of spec. Biggest difference was new sensors, originals were failing and giving spurious C28 codes and false readings. Gotta make sure throttle cables are correctly adjusted too.
The secondaries can also be actuated from under the throttle bodies as Will14 says, to set and adjust the sensor, but to observe them working, a look inside the airbox is needed