GSX1400 Owners .org

Technically Speaking => Fuelling => Topic started by: AndyB on Thursday, 25 February 2021, 05:54 AM

Title: Fast idle cure
Post by: AndyB on Thursday, 25 February 2021, 05:54 AM
Another school day ,
My fast idle has only ever worked twice.that was after I disconnect the clutch switch & cleaned the contacts. Then went back to not working.
So I knew it wasnt TP censor etc.
Long story short...disconnected the earth today to set the time clock , I always ,as a matter of course wire brush the terminals and what ever is connected to it .
Turned it on ..clock is set to 1 oclock..... cool
Fired her up and boosh......fast idle is working......not only that its showing a 0.2v increase on tick over
Maybe worth a shot if anyone else's fast idle is acting the goat...
Title: Re: Fast idle cure
Post by: Eric GSX1400K3 on Thursday, 25 February 2021, 09:59 AM
Thanks Andy B, might give that a go. Went for a ride last weekend, let the bike  "warm up" before  i set off, (it was 34deg c ambient), fast idle started at 2000, then dropped off to 1500 quite quickly  before settling at 1100rpm normal idle.  Rode away and 5 min later had the flashing F1 light, code C28 that indicates STP fault. Cycle ignition, code cleared and did not return for the rest of the ride.

Im suspecting either  a faulty stp sensor, or a failing secondary actuator, but will check terminals and connections anyway.
Title: Re: Fast idle cure
Post by: Hooli on Thursday, 25 February 2021, 02:38 PM
C28 can be caused by the throttles out of balance too, the ECU detects the error by comparing the TPS to the SPS so a big imbalance across the TBs can trigger it.
Title: Re: Fast idle cure
Post by: Hooli on Thursday, 25 February 2021, 04:35 PM
I almost forgot, reset the position for the TPS and SPS too.
Title: Re: Fast idle cure
Post by: grog on Thursday, 25 February 2021, 05:58 PM
Andy, just wrote similar recently. Mine wasnt as smooth as normal. Did the old negative wire remove, connected to positive. Drains everything. Running perfectly afterwards. Not supposed to work on our basic ECU but seems to help, did on yours and mine.
Title: Re: Fast idle cure
Post by: Hooli on Thursday, 25 February 2021, 07:31 PM
Our bikes work on voltage sensing for the sensors so a dodgy earth could reduce the voltage across the systems to give them incorrect readings, which might be cured by removing it & replacing it as that's likely to clean the contact area a bit.
Title: Re: Fast idle cure
Post by: Eric GSX1400K3 on Thursday, 25 February 2021, 08:29 PM
Cheers for that, will clean terminals, check tps and stp settings and  rebalance tb's.
Title: Re: Fast idle cure
Post by: The Stumeister on Sunday, 16 July 2023, 08:36 PM
quote author=grog link=msg=80653 date=1614239912]
Andy, just wrote similar recently. Mine wasnt as smooth as normal. Did the old negative wire remove, connected to positive. Drains everything. Running perfectly afterwards. Not supposed to work on our basic ECU but seems to help, did on yours and mine.
[/quote]
Sorry but i don't quite get what you did...Did you disconnect the earth cable from the battery and connect it to the positive terminal on the battery and leave it for 5 mins or so..? I'm trying to try as many options of the fast idle fix as i can.....cheers
Title: Re: Fast idle cure
Post by: Eric GSX1400K3 on Sunday, 16 July 2023, 10:52 PM
I think what Mr.Grog means is a hard reset.  Disconnect both leads from the battery and then join both leads together temporarily without the battery.  If leads are too short, remove the battery.  Joining them together is supposed to discharge any capacitors in the system and resets any learned values in modern ecus.  The ones on our bikes aren't modern, but a hard reset does appear to help.  Remember, the battery is not included in this when you join positive and negative terminals.  Don't connect the negative lead to the positive battery terminal and vice versa, you will fry the ecu amd all other electrical parts on the bike then...
Title: Re: Fast idle cure
Post by: The Stumeister on Monday, 17 July 2023, 12:30 AM
Ah ok,so disconnect both the positive and negative leads and connect the 2 together but NOT on the battery which is left well alone.....Then leave it for 5 or 10 mins then connect as usual? Do i leave ignition off or on? Thanks.
Title: Re: Fast idle cure
Post by: seth on Monday, 17 July 2023, 02:03 AM
Quote from: The Stumeister on Monday, 17 July  2023, 12:30 AMAh ok,so disconnect both the positive and negative leads and connect the 2 together but NOT on the battery which is left well alone.....Then leave it for 5 or 10 mins then connect as usual? Do i leave ignition off or on? Thanks.

On or the circuit your trying to drain wont be complete
Think of wiring as plumbing it needs a complete circuit to work
Title: Re: Fast idle cure
Post by: grog on Monday, 17 July 2023, 10:00 AM
Negative lead off can be connected to positive still connected to battery, no probs.
Title: Re: Fast idle cure
Post by: The Stumeister on Saturday, 29 July 2023, 09:43 PM
My fast idle still isn't kicking in like it used to before but today i fired up the bike,started 1st push of the button and sat there approx 12-1300 rpm then dropped to 1100 or so and i just let it idle for a minute while i put my helmet on then rode away on it without any issues........just wondering,if my oil temp sensor was faulty would the bike still start 1st time or run very rough..?
Title: Re: Fast idle cure
Post by: KiwiCol on Sunday, 30 July 2023, 04:17 AM
Quote from: The Stumeister on Saturday, 29 July  2023, 09:43 PMMy fast idle still isn't kicking in like it used to before but today i fired up the bike,started 1st push of the button and sat there approx 12-1300 rpm then dropped to 1100 or so and i just let it idle for a minute while i put my helmet on then rode away on it without any issues........just wondering,if my oil temp sensor was faulty would the bike still start 1st time or run very rough..?


I'd wait till you get back to the cold weather, then assess if it's working or not.  When the ambient temp is 'pleasant' obviously the engine & oil are warmer than when it's at 3 degrees ambient.  In warmer weather it does not need as much warm up time as it's warmer to begin with.
Title: Re: Fast idle cure
Post by: Speedy1959 on Monday, 31 July 2023, 03:50 PM
Quote from: The Stumeister on Saturday, 29 July  2023, 09:43 PMMy fast idle still isn't kicking in like it used to before but today i fired up the bike,started 1st push of the button and sat there approx 12-1300 rpm then dropped to 1100 or so and i just let it idle for a minute while i put my helmet on then rode away on it without any issues........just wondering,if my oil temp sensor was faulty would the bike still start 1st time or run very rough..?
Mine does the same but it is a "Balmy" 17 - 19C here at the mo

S.
Title: Re: Fast idle cure
Post by: grog on Monday, 31 July 2023, 04:58 PM
Exactly correct, warmer weather hardly any fast idle. Speedy,its 5pm here Winters arvo. 22 degrees,it is a bit of a one off.Usually less than that.
Title: Re: Fast idle cure
Post by: The Stumeister on Thursday, 03 August 2023, 03:30 AM
I live in Scotland so we rarely get much of a summer and warmer temperatures...just slightly less colder rain. Would it be an issue for me just to turn the tickover up when starting it and just turn it down again when the engine is warm..?
Title: Re: Fast idle cure
Post by: Hooli on Thursday, 03 August 2023, 05:29 PM
Not an issue at all, but sounds like a faff every time.
I'd just start it & ride off, within a few hundred yards it'll be warm enough to idle ok.
Title: Re: Fast idle cure
Post by: grog on Thursday, 03 August 2023, 05:35 PM
Exact as Hooli said.