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Discussion Starter #1
Hi - New to MV's and hoping someone can shed some light on this:

I have a 2009 989R on which I've just installed new MVA Corse headers (without cat of course) and matching race ECU. Supplier said to ditch the lambda sensor, even though there is a hole for it in the midpipe. Bike runs great, nice improvement over stock, except at iddle, where it seems to 'cycle', that is iddle cycles between say 1000-1200 rpm. After putting on the pipes/ecu, I took it into the local Duc dealer (no MVA dealer around) to reset the TPS and he said this is normal without lamda sensor.

Questions:

1. Is this supposed to happen with this config?
2. Any advantage to reconnecting lambda sensor?
3. Is new ECU setting just going to disregard lambda anyway?

Cheers
Cas
 

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1. As a general rule, no. There can be some surging due to the fueling being rich until the engine is up to temperature though.
2. No.
3. Yes.

I suggest you call OzRacing in Carina and get him to do a throttle body balance and TPS reset. If necessary make sure the fuel and plugs are fresh.
 

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Discussion Starter #3
Thanks Revhead. TPS reset and balancing was done. Fuel fresh and plugs changed recently. Runs fine above iddle.

Surging is a better term than cycling... Engine iddle surges in rythm up from 1000 to 1200 rpm, then back down, etc... when started but continues doing it when even when engine is nice and warm/hot.

I can live with it I guess but wondering if others have this issue and whether there is a fix.
 

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I am sure your ecu is the 5sm ,did they use vdsts software to adjust the tps and also to adjust your fuel trim.

I live in cashmere and have the software

cheers eddy
 

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Your Duc dealer didn't do you any favors, even though his intentions might have been good. They might not really know how to dial your bike in properly based on his comment about the lambda . As stated before, your idle might surge for a minute or two when the engine is stone cold. But when your warmed up enough, the idle should be stable. I have the same set up as you do. My idle started to surge a week after my exhaust got installed. I took it to my MV dealer, and he straightened it right out.
 

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Your idle speed is too low. Plain and simple.
Have idle speed corrected (part of throttle synch using air bleed screws) and confirm TPS setting....kit ECM allows idle CO % trim.....that needs to be reset as well.

Bottom line thoughs your hunting/surging idle speed when warm is because the idle speed is too low and cam timing overlap is causing reversion in the intake tract.

Kind of sounds like a big bore "lumpy camshaft" hot rod V8 doesn't it?
 

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Discussion Starter #9
Cheers guys, will order a fiat/obd2 and connect it to MDST and see what the setup is. Duc tech probably does not know what he's talking about.

ECU is indeed a 5SM. Home is Brisbane (Enoggera) but I'm currently un New Caledonia for a 2-year job and bought the 989R to have a bit of fun.
 

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Discussion Starter #10
Update and need for more advice please:

Bike has now been to 2 more shops, unfortunately not MVA specialists: TPS reset, trim and synched. Bike still surges at iddle but I can live with that. The problem is now that the engine cuts off on decel. Off the gas, clutch pulled in, revs drop and engine cuts off. Does this on and off (pardon the pun) with more or less regularity.

Thoughts?
 

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Did anyone replace the chain tensioner on your bike ,if you drop one tooth it will hunt at idle ,does not matter what you try and do ,you will never stop it hunting ,again i have no idea what has been done to your bike .if you have no luck Pm me and come over one day ,i have all the gear to try and help you,i live at cashmere. cheers eddy.if you want my software or anything else.I can adjust the Co and fuel trim at idle ,

cheer eddy
0428 756 275
 

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He shouldn't need a new tensioner as it is a later model...

If the idle is not at 1200~1400 it is too low. This will cause surge and hunt at idle and stalling on decel.
Get them to raise you idle speed to 1300 when warm.
 

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There is a CO adjustment setting that adjusts the fuel trim. Should be set around 0. My 990r did the same thing as yours. To correct it the dealer leaned out the trim with this adjsutment to -15, bike idles perfect now. It changes the injector pulse I believe.
 

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The Co i have found varies from bike to bike ,my fuel trim is at + 15 ,There all different.and different bikes.glad this works well for you.
 

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He shouldn't need a new tensioner as it is a later model...

If the idle is not at 1200~1400 it is too low. This will cause surge and hunt at idle and stalling on decel.
Get them to raise you idle speed to 1300 when warm.
Definitely will cause that problem so get the idle higher
 
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