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Poor idle on 885i Girly

Started by the slow heart, February 12, 2024, 05:50:52 AM

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the slow heart

Hi guys,

my ponie kept idling evenly about 900 rpm even on cold starts. But resently problem evolved and requires bit of throttle to keep it idle when cold. Did the tuneECU and all tests went ok, no errors, sensors ok. My suspect are the IACV lines. Shall I replace them with gasoline resistant rubber hoses, or the high temperature silicone ones would be ok?

It should be mainly air I suppose, but some gasoline fumes also.


I've replaced the ones on my Daytona with silicone vacuum hose. I've had a quick look back to see what internal diameter it was & how much I ordered. It was 7mm ID and 2m length (bought extra as I was going to replace the vac lines on the Tiger too), so I suspect 1m would be enough. The important thing is to make sure you have enough so none of the hose is bent too much when you fit it.

To be honest, either rubber fuel hose or silicone hose would do as long as it doesn't collapse under a mild vacuum.
No matter how smart you are you can never convince someone stupid that they are stupid.

the slow heart

being not sure how much vacuum varies at the manifold, you might be right that soft silicone could shrink.

Will try to fit the thick braided gasoline resistant rubber ones. Anyway, not much space to bend them easily.

the slow heart

Changed the IACV lines and bike is idling really well at around 1200 rpm cold. Reading other topics here I see my idle fuel trim (co) and iacv are a bit different. First one 19.5, second 175. Air temp sensor is another suspect for showing higher numbers than real and have to test it to see are the above settings masking another problem.

My bike is without lambda sensor, is it ok to add one, or is it more complicated than just providing the seat for it on the pipe?


From memory, my 955i idles around 1200rpm, so I think you've probably done what it needed. Don't know about the Lambda sensor though, my knowledge of electrickery is not great (see Daysie's diary). I know some owners remove the lambda sensor & fit a sensor bypass (think my bike came with one in a box but I never fitted it). Earlier bikes never had one so I'm unsure what the benefit would be of fitting one restrospectively, not even sure if the wiring to the loom is there.

As for the IACV & fuel idle trim, these are calculated by the ECU., as I'm sure you know  & it collects data from all sorts of other sensors, including air barometric pressure & air and coolant temperature, so it's difficult to know whether the readings you're getting are good or not. I've had a look through the Triumph Service manual & it doesn't give any figures, only the range, i.e. for the IACV it's 0 - 180, where 180 is fully open, so I agree the IACV reading does eeem a little high. If you have TuneECU, I think you can adjust them. From memory around 35-40 isd about right although mine is around 60.

Out of curiosity, do you know what map you're running?

No matter how smart you are you can never convince someone stupid that they are stupid.

the slow heart

Thanks, Lee, my bike is year 2000, and lambda socket is pending open in the loom just under tha battery left side.

I saw the option to adjust them in TuneECU, but still collect information. My current understanding for the idle trim fuel (co) setting is that it is a manually preset value for use by ECU, due to the absence of actual reading by lambda sensor i.e. plugged in sensor will provide co value ( correct if probe is working properly ) and the manual figure will be out of use. But I might be wrong. I saw few lambdas in ebay, none in worldoftriumph and think of getting one. If you or other fellow rider here has one not needed, please let me know, I could buy it.

The map on board is the standard 1 of 3 for the model, without catalisator, with standard exhaust. The detail is that when settings in question were preset, bike was not mine, and the map was some obsole one, unrecognisable for the TuneECU app ( hence the reason I swapped it to get app connected to ECU ). Might be the obsolete map once before required higher idle fuel trim and iacv. Anyway, whithout gas analyser/ proper lambda I cannot be sure what is purged off. I am not that skilled to judge the correct settings by feel of the bike performance/ spark plugs condition.

And by the way valves were done just before 5 000 km, all in midrange of specs. Total 85 000 km on the clock. Hot idling is smooth music, thinking throttle bodies sync is not necessary.

the slow heart