lean idle with closed loop fuelling

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9c1vs
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Joined: Sun Sep 29, 2013 10:33 pm
cars: 9c1 vs 5spd

Re: lean idle with closed loop fuelling

Post by 9c1vs »

Holden202T wrote:I would think either the idle afr tables has 14.7 values or its not going into idle afr table .....

personally i'd be making sure its not going into closed loop at idle and then using the wideband to dial in the idle fuel, then if you want to use closed loop idle after that you can, but I'm not sure why you'd want to as apposed to using the normal idle afr table ?

also keep in mind closed loop fuelling is different to closed loop idle.
Currently i have it using the main table. I wasn't bothering with the idle fuel table ad it is only a small cam. Having said that trying to get it to idle stable has been difficult. Is the idle table a prefered option? I had the target afr set to 14.7:1 as it seemed to make little difference to 14:1 and the change from 14.7 to 14:1 was causing the idle to become instable and not settle.
9c1vs
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Joined: Sun Sep 29, 2013 10:33 pm
cars: 9c1 vs 5spd

Re: lean idle with closed loop fuelling

Post by 9c1vs »

pman92 wrote:Is the wideband 0-5v offsets set?
Is the wideband measuring the opposite bank or somewhere different to the narrowband?

They sre set and the wideband is in a different location, but the readings were always the same with the other ecu and they match when cruising.
Dylan
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cars: VR Commodore V8

Re: lean idle with closed loop fuelling

Post by Dylan »

Is the NB heated? 2 wire sensors at idle can be unreliable especially with a decent camshaft. Low air flow and cooler gas too.
9c1vs
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Joined: Sun Sep 29, 2013 10:33 pm
cars: 9c1 vs 5spd

Re: lean idle with closed loop fuelling

Post by 9c1vs »

Dylan wrote:Is the NB heated? 2 wire sensors at idle can be unreliable especially with a decent camshaft. Low air flow and cooler gas too.
Its just the stock 2 wire sensor.
Dylan
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cars: VR Commodore V8

Re: lean idle with closed loop fuelling

Post by Dylan »

I'd be inclined to adjust off the wideband. If they match up during driving that's a good sign.
Post up a picture of a spark plug after a warm idle at 15.xxAFR on the wideband.
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Holden202T
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Re: lean idle with closed loop fuelling

Post by Holden202T »

yeah I agree, if the narrow band is not heated I wouldn't trust it at all at idle!
9c1vs
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Joined: Sun Sep 29, 2013 10:33 pm
cars: 9c1 vs 5spd

Re: lean idle with closed loop fuelling

Post by 9c1vs »

Excellent thanks for the help. I'll throw a pic up when i get a chance.
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