Fast Idle in ambient temps

[imweirdimnotsocial21]

Hi everyone!

New owner here (bought my K2 a week ago), read through a few or most of the "fast idle" posts, and I am still unsure if I have an issue with my STP servo mechanism or not!

So, let me list you what I have done already:

1. Disconnected TPS --> Adjusted it all within spec by measuring the resistance of the TPS connector to the loom sitting at 1,107kΩ fully closed and ~4.3kΩ when fully opened. Haven't measured the resistances in the big gray plug connecting most of the loom to the ECU, as it was quite difficult to unplug it, it wouldn't budge so I didn't push it too much.
2. Disconnected STP Servo --> Measured the resistance there, according to Haynes manual it should be between 4.5Ω to 7.5Ω; mine was sitting at 5.5Ω.
3. Disconnected STP --> Adjusted it all within spec by measuring the resistance of the STP connector to the loom sitting at 0.8kΩ fully closed (If I pushed REALLY HARD with my finger, it might drop too 0.75kΩ) to 3.5kΩ when fully open (if I pushed really hard, it would also measure higher).

Connected everything back together after cleaning it with contact cleaner and nothing... No fast idle.

Bike is slightly "lumping" at 1k RPM, not running like a clock, but runs alright. I will have to balance the TPs as well, but that is a different job. Sometimes, at night especially, I can hear small misfires from the LHS exhaust, so something is happening on TB n2 between cylinders 3/4.

Key measurements: today it was warm in Warsaw, Poland, maybe 15c ambient. So the oil shouldn't have been colder than that...

Why the heck isn't the fast idle working as it should?!?!?!? The bike is a queen now, New Oils, New Air Filters, New Iridium Spark Plugs, New Oil Filters, break pads, etc etc...
When I was buying the bike from the owner, 1 week ago, in its shitty condition, with shitty spark plugs, cylinder 3/4 being visibly darker than 1/2, during the first start up, it did have fast idle, and the weather wasn't colder or significantly colder.

Could it be me fucking it up by disconnecting the battery and the clocks all together (the select button was fucked, I had to rip them apart to fix it), and connecting all the charger mumbo jumbo on it for voltmeter readings ?!?!?!?

Please help me with this, as I would love to understand what could be the issue and how to fix it!

I appreciate all your prompt replies and wisdom sharing!!!!!

Thanks!

[KiwiCol]

I know there is a correct order in which to balance the TB's & set the TPS.

You need to balance the TB's first, then set the TPS, they both have to be correct to get a smooth running motor.  Once you've got these done, then you can adjust the idle to 1100rpm (some folk like 1200rpm). Start the bike & get it up to temp first then adjust idle via the black knurled knob located under the throttle bodies on the left-hand side of the bike.

The fast idle will only come on if the bike is cold, 15 degrees should be cold enough to activate it, but probably only for 20 seconds or so.

[KiwiCol]

Your plugs 3/4 being darker could be caused by the TB's being out of adjustment (over fueling)    Get them set first & see how she goes from there. The fast idle may just come back into operation on it's own after a few starts / runs.

[Eric GSX1400K3]

What KC said, balance the TBs first. From my recent investigations, TPS closed and STPS fully open are the key readings, if they're in spec you've got a good chance.

A way to check if the STVA ("fast idle") is working is to remove the air filter, and while looking into the airbox, switch on the ignition (don't start the engine) and watch the secondary throttle butterflies move through their range of motion. Its a quick flick up and back, but this confirms the STVA motor is working.  The rest is then up to the TPS and STPS sensors. 

These can also be bad, they get corrosion on the internal tracks and cause spurious voltages which mucks up the fuelling.

New one sensors from webike Japan are the cheapest, about 160AUD each, still better than over 300aud from auzuki direct.

Re spark plugs, iridium plugs are overkill, std proper NGK's do just fine.  Make sure you use a good quality synthetic oil, but thats a whole other can of worms....

[imweirdimnotsocial21]

Thanks everyone!

Ok then, time to rinse and repeat hehe.

I am unsure about how the bike was ridden or maintained by the previous dude, but heck, she's getting love from me now.

I'll balance the TBs as you guys said and then will repeat the process.

Will keep ya posted!

[grog]

Mate, at 15c don't reckon my fast idle stays on 15 seconds.Never a problem riding hot or cold. Get your idle up a touch, 1100-1200, that sure does give a different feel & sound resting. Set it all up, then don't mess with it, just ride. Not broken, don't fix it. Iridium plugs, work same as standard, I use iridium NGK, just what I like🤷🏼 Fit genuine or K&N air filter, better flow than aftermarket.Enjoy 👍😀BTW dealer mode check for tps is good, there to use as so easy.

[Hooli]

Make sure you use a good quality synthetic oil, but thats a whole other can of worms....

Oh massive can of worms as the only 14s I've ever heard of with leaking valve stem seals ran fully synth, never heard of a bike on semi synth suffering that.

[imweirdimnotsocial21]

Make sure you use a good quality synthetic oil, but thats a whole other can of worms....

Oh massive can of worms as the only bikes I've ever heard of with leaking valve stem seals ran fully synth, never heard of a bike on semi synth suffering that.

I am running Castrol Power1 Racing 4T 15W-50. Was running the same on the bandit, no issues. Helps keep the oil viscous enough when in traffic and oil reaching +100 delicious degrees temps.

But yeah, oil is a can of worms. I remember somewhere I read an epic comment "if you're ever lost in the woods starting shouting about the right oil in your car, and you'll summon all the gear heads to your rescue".

Hahaha lol

[grog]

Mate, Bandit pretty much same as 14 for oil, adjustments etc. Suzuki very good that way, even SV,Busa, Boulevard very easy to adapt to👍

[Will14]

Also worth checking that the clutch switch is working correctly, it has been known for them to be bridged out or fail, which really cocks up the fueling & prevents the cold start from functioning. My experience the aftermarket switches are cheap & do the job but the difference I found when fitting a genuine clutch switch was night & day in a positive way

[imweirdimnotsocial21]

Also worth checking that the clutch switch is working correctly, it has been known for them to be bridged out or fail, which really cocks up the fueling & prevents the cold start from functioning. My experience the aftermarket switches are cheap & do the job but the difference I found when fitting a genuine clutch switch was night & day in a positive way

Hey Will!

By clutch switch do you refer to the button that gives signal to the ecu when it is pulled in?
If that would be faulty, wouldn't starting be an issue?