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yeah mine go directly from tb to iacv. check your idle trim and your iacv adjust in tune ecu as well made a huge difference on mine last night
 

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thanks guys - all sorted

Thanks guys all sorted - i orig replaced the iacv hoses with silicon hoses - they were collapsing and causing all the grief. Luckily i kept the corrugated iacv hoses - bit of bodging and heat shrink and all sorted - running super smooth again !
cheers
Dell
 

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so what does the adjustment in TuneECU for the idle adjust actually do? I tried setting it from -15 to 15, it was a touch low idle at -15, and a touch high at 15, but its not happy very much anywhere. also, how does this combine with the idle fuel trim to change idle speed?
 

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link to info from

so what does the adjustment in TuneECU for the idle adjust actually do? I tried setting it from -15 to 15, it was a touch low idle at -15, and a touch high at 15, but its not happy very much anywhere. also, how does this combine with the idle fuel trim to change idle speed?
Hi dicho
I had a great discussion with d'eccosse and tom (tuneecu) on the settings here http://www.triumphrat.net/ecm-and-fi-tuning-help-tips-and-tricks/197948-1999-mc2000-sprint-st-tuneecu-trim.html#post2139829
All the info you need is posted there mate, but for speed it sounds like the -15 to 15 you are setting is in the test tab for adjust iacv ? if so all you are doing is adjusting the position of the stepper motor. The stepper motor allows air to flow into the throttle bodies at idle, so when on a run the setting you are talking to will not affect anything, only at idle. The idle fuel trim CO is a made up value (not a real percentile) as it happens mine was pretty close to the real CO emissions. If i was you i wouldn't mess if you don't have access to a gas analyser esp if the bike is running fine.
**Note the bike has to be at operating temp before the settings will take. If you have a newer sprint 2000 on(non mc2000 ecu) with a closed looped system, then messing around with the idle fuel trim won't help, the ecu will just re adjust your settings. (Easy way to tell is if it the exhaust has a lambda sensor its the newer closed loop).
Hope i haven't muddied the waters here.......
almost all uneven idle in these models usually comes down to one of these five things
start at the top and work down
1) air leak on iacv hoses, easy test is to take them off and do the old finger over the end blow test lol any leaks = bad idle
2) faulty/dirty stepper, i carefully carb cleaned mine then re greased with lithium grease - worked wonders
3) bad fuel/ filter /pump
4) unbalanced throttle bodies, surprisingly easy to do with a couple of vaccum gauges and patience.
5) valve clearances
 

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Hi dicho
I had a great discussion with d'eccosse and tom (tuneecu) on the settings here http://www.triumphrat.net/ecm-and-fi-tuning-help-tips-and-tricks/197948-1999-mc2000-sprint-st-tuneecu-trim.html#post2139829
All the info you need is posted there mate, but for speed it sounds like the -15 to 15 you are setting is in the test tab for adjust iacv ? if so all you are doing is adjusting the position of the stepper motor. The stepper motor allows air to flow into the throttle bodies at idle, so when on a run the setting you are talking to will not affect anything, only at idle. The idle fuel trim CO is a made up value (not a real percentile) as it happens mine was pretty close to the real CO emissions. If i was you i wouldn't mess if you don't have access to a gas analyser esp if the bike is running fine.
**Note the bike has to be at operating temp before the settings will take. If you have a newer sprint 2000 on(non mc2000 ecu) with a closed looped system, then messing around with the idle fuel trim won't help, the ecu will just re adjust your settings. (Easy way to tell is if it the exhaust has a lambda sensor its the newer closed loop).
Hope i haven't muddied the waters here.......
its a 2000 sprint st, but no closed loop system, a 49 state bike, not california or europe emissions.
the problem is, that its NOT running well.
 

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help

almost all uneven idle in these models usually comes down to one of these five things
start at the top and work down
1) air leak on iacv hoses, easy test is to take them off and do the old finger over the end blow test lol any leaks = bad idle
2) faulty/dirty stepper, i carefully carb cleaned mine then re greased with lithium grease - worked wonders
3) bad fuel/ filter /pump
4) unbalanced throttle bodies, surprisingly easy to do with a couple of vaccum gauges and patience.
5) valve clearances

If your checking the hoses, be as well to clean the stepper and balance the throttle bodies whilst there, considering the time involved removing tank and assemblies.
best of luck
 

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2) faulty/dirty stepper, i carefully carb cleaned mine then re greased with lithium grease - worked wonders
Can someone explain what's getting greased? Is it just the o-ring? Is there a moving part in the stepper that's good to grease?
 
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There's just an O-ring on the piston but I seem to recall taking it apart did not go well for me.
It's been so long but some disaster transpired so I bought a replacement and put a little white lithium grease on the bore.
Someone chimed in and said bad move but no problems since.
 

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Hmm, is there a spring in there that makes assembly difficult?
 

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Thanks for chiming in Steve and DEcosse.

I got that notion from this thread.

6. Remove and save the o-ring on the stepper motor. Inspect the stepper motor plunger for carbon and/or oil buildup and dirt. You can use carb-choke cleaner to clean things off, or put some brake cleaner on a lint-free rag. Blow off the plunger well with air, making sure it's dry. Blow out the electrical connector. If excessive oil was on the plunger or case, you'll want to remove the vacuum lines from the throttle bodies and blow them out with carb-choke cleaner and air.

I've never dug into the ISCV (IACV - why did they change the name?) before and I haven't a pic to show me what the innards look like, so I'm poking in the dark.


Symptoms: Idle is at about 900 rpm - quite anemic, so I find myself 'nursing' the throttle to ensure it doesn't stall, which it does occasionally.

I've tried some easy-to-do possible fixes: cleaning the injectors with Techron and replacing the cracked ISCV hoses. The latter had me thinking that I solved the problem as the engine idles at 1200rpm for a minute or two, but then returns to the low idle.

So I was thinking the next step would be to check out the ISVC stepper since I've read that that solved the problem for some, and do a TBS while I'm at it - made a nice DIY manometer yesterday.

I'm happy to hear suggestions. :ear
 
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