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Heat related.idle weirdness

Posted: Tue Jul 16, 2019 8:38 pm
by KitchenSync
In neutral, after the 30 min ride home and stuck in city traffic the idle gradually edges up to 3,000 as things get warmer and warmer. If I press the gear change down enough for the neutral light to out, the idling drops to it's normal 1,250ish, but eventually after lots of sitting in traffic and the fans coming on, even that normal idle starts to rise to 2,000+.

This couple of snapshots from TuneECU show with and without the neutral light out. Clearly the idle.control valve and fuelling are being triggered by 'something' to react.

When cold everything behaves normally, although I can still trigger a drop in idle speed by putting the bike in gear or half-pressing the gear lever so the light goes out.

Is very very consistent in its behaviour and I'm baffled - it makes slow traffic a nightmare.

The only thing I can see is the ambient air temperature is off the charts so I'll try pulling the wires off to see if it stabilises.

Any other ideas?

Posted: Sat Jul 20, 2019 7:48 pm
by D-Rider
Sorry - although I've had my Futura for a couple of years now, I haven't really got round to fiddling with it yet so I'm not much help.

Posted: Mon Jul 22, 2019 1:04 pm
by KitchenSync
It's a "feature" I've seen written about elsewhere, but the other way round - neutral light dropping revs. Could there be a bug in the software? I guess the only way out is to have it mapped at a cost no less than half the value of the bike.

I've not pulled the air temp thermistor yet - figured if I can take a resistance reading at normal temperature and just jab a resistor of similar value the ECU won't awaken from it's slumber and go all "eh... what... there's something wrong...". Although a quick search will doubtless find it only costs £2.21 when fitted to a Citroen but £835.31 when supplied in an Aprilia bag.

Posted: Mon Jul 22, 2019 1:56 pm
by KitchenSync
Found a long thread on Futura wiring problems that could be the root of many quirks... ... ratic-Idle

And in conclusion....

Posted: Tue Jan 07, 2020 11:25 am
by KitchenSync
I just renewed my TPS following several weeks of escalating jerkiness. Error log showed the TPS was at fault and sure enough, when warmed up nicely and idling at 3k in neutral TuneECU was showing a throttle that was 4% open, the 0%, then 4%, then 0% - hence riding like the engine was being turned on and off as I bumbled about. So I renewed it with an £8.99 Citroen Berlingo part. The rotating part of the TPS is sprung closed, and with the new one plugged in it was reporting the throttle as 12% open. "Odd I thought:... fitted it anyway, cleared the error logs, ran a TPS reset and it zeroed.

Bike started fine, no more variation in readings so I zipped it up and went for a ride. Ye gods what a difference. It feels like its got 20% more power (57k on the clocks), the exhaust no longer reeks of over-rich unburnt fumes, and get this.... the whole rising idle when the neutral light is lit has disappeared. Rock solid and pulling like a train. Best £8.99 I've ever spent - fixed several years worth of annoying oddities plus the recent faltering.

Waiting for the next thing... I think it's the disintegrating front S22 - pretty sure they're not supposed to do that.

Re: Heat related.idle weirdness

Posted: Tue Jan 07, 2020 5:20 pm
by mangocrazy
Well done you for your persistence in tracking down the culprit...! Does the Fut have a different ECU and management system to the Falco and Mille? (I seem to remember that being the case). The fact that you can use TuneECU on the Fut would seem to indicate so.

Re: Heat related.idle weirdness

Posted: Tue Jan 07, 2020 6:26 pm
by fatboy
Well done, once again you fought on when some would have given up!
TuneEcu is a bit good innit !