Fast idle in warmer temps

[imweirdimnotsocial21]

Thanks mate.

What was the reason you adjusted yours? I read in the forum that adjust the screw causes more problems than brings solutions.

[imweirdimnotsocial21]

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!

[Hooli]

Thanks 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.

[imweirdimnotsocial21]

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.

[Hooli]

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.

[imweirdimnotsocial21]

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

[Hooli]

Good luck with it.

[Hooli]

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.



Hopefully it's easier to visualise what happens now.

[imweirdimnotsocial21]

You're a champ mate! Thanks for sharing!!!!!

[Will14]

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 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

[imweirdimnotsocial21]

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 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.

[Eric GSX1400K3]

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.

[imweirdimnotsocial21]

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.

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.

[Will14]

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.

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

[imweirdimnotsocial21]

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.

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