Tech Tip: Fast idle cure

[AndyB]

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...

[Eric GSX1400K3]

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.

[Hooli]

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.

[Hooli]

I almost forgot, reset the position for the TPS and SPS too.

[grog]

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.

[Hooli]

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.

[Eric GSX1400K3]

Cheers for that, will clean terminals, check tps and stp settings and  rebalance tb's.