sled really rich at idle

[BigFish BC]

i have been fighting a rich condition at idle up to about 4500rpm then when boost comes on it cleans out for a bit, unless i hold it to the bar for a bit then it will start to miss a bit again.to me it seams like i have a bad stock injector but looking for ideas,the sled will not idle unless i hold the throttle a bit & sometimes have to bump throttle to get it to start.fuel pressure is perfect at 35lbs.my a/f is at 10.5-11.5 at idle,have tried lowering my co no help,looking for ideas.

 

[Coxy]

Might be worth checking the tps numbers, make sure it is smooth through the range. Try bumping your box threshold up a little to rule out it firing the aux injectors a tad early. The odd day mine needs moved up a little to behave on the trail, vs what it likes in the deep. Just a couple things to look at for fun.

Might be worth checking your exhaust/turbo over as well. If it has to work at all to get air through the turbo it'll go rich, ie not getting full exhaust flow or impeller starting to bind up?

 

[icr]

If there's a ticking noise it's an exhaust leak

 

[gulfi]

how to fix it.

you "only" need to lower the "CO"

you bridge two connectors in the wireharness and change it from the display.
ask a Yamaha dealer if you are unsecure.

 

[BigFish BC]

you "only" need to lower the "CO"

you bridge two connectors in the wireharness and change it from the display.
ask a Yamaha dealer if you are unsecure.

tried that did nothing.

 

[BigFish BC]

If there's a ticking noise it's an exhaust leak

no exaust leak + pressure tested system.

 

[BigFish BC]

Might be worth checking the tps numbers, make sure it is smooth through the range. Try bumping your box threshold up a little to rule out it firing the aux injectors a tad early. The odd day mine needs moved up a little to behave on the trail, vs what it likes in the deep. Just a couple things to look at for fun.

Might be worth checking your exhaust/turbo over as well. If it has to work at all to get air through the turbo it'll go rich, ie not getting full exhaust flow or impeller starting to bind up?

have checked & tried all this.

 

[M5-]

I think my next step would be the injectors, what does the A/F read when it starts to burble? You have a boost it fuel system now right, maybe one of the auxiliary injectors is firing at idle

M5

 

[BigFish BC]

I think my next step would be the injectors, what does the A/F read when it starts to burble?

M5

af is 10.5 -11.5 at idle all the way to 4500rpm then as boost comes on it cleans out

 

[BigFish BC]

if anybody has some good stock injectors they want to get rid of let me know.

 

[NM]

How is your idle air hose getting air?
You could try unplugging the XIC and running it to rule out the extra injectors.

 

[BigFish BC]

How is your idle air hose getting air?
You could try unplugging the XIC and running it to rule out the extra injectors.

you got me on that,witch is my idle air hose.

 

[08nytromtxa]

you got me on that,witch is my idle air hose.

It's the hose coming off the bottom of your throttle bodies. About 1/2" hose. Will either have a small filter on it or just open ended. If you can reach it when sled is idling try plugging it off to see if it makes a difference.


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[BigFish BC]

yah mine has the filter will check it.

 

[BigFish BC]

one other thing i forgot to mention is that if it sit for a long time & i start it it idles fine for 30 sec to a minute at 14.5 a/f then slowly starts creeping up to 10.5 to 11 a/f & dies unless i give it some throttle.it does act like its being choked but of coarse efi dont have a choke.i know the ecm just adds more fuel,guess it could be air intake sensor malfunction,but you would think i would get a code.

 

[BigFish BC]

How is your idle air hose getting air?
You could try unplugging the XIC and running it to rule out the extra injectors.

unpluged box no change,checked the idle air hose filter is fine & so is hose.

the one thing i did find now is if i lower my fuel pressure to 25lbs at idle it comes up to 13.8 & idles perfect,maybe my fuel pressure gauge is done will try it like that for a ride.

 

[08nytromtxa]

unpluged box no change,checked the idle air hose filter is fine & so is hose.



the one thing i did find now is if i lower my fuel pressure to 25lbs at idle it comes up to 13.8 & idles perfect,maybe my fuel pressure gauge is done will try it like that for a ride.

You running a 1:1 malpassi ?


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[BigFish BC]

You running a 1:1 malpassi ?


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cant remember off the top of my head it one neil gave me when i did the original boost it kit.

 

[08nytromtxa]

cant remember off the top of my head it one neil gave me when i did the original boost it kit.

It's probably that one then I assume. Is it plumbed to see vac or boost only?


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[BigFish BC]

It's probably that one then I assume. Is it plumbed to see vac or boost only?


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yup got the little one way valve,to see boost only.

i was talking with dean at alpine looking for stock injectors,he said they have had a bunch of the coolant temp sensors go & it does exactly what mine is doing.so have new one coming & will try it,i guess when they go they default to coldest temp so it will put it in a really rich condition at idle.