Forced open loop fuel tuning

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ajpturbopittsburgh
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Joined: Wed May 26, 2010 10:58 am

Forced open loop fuel tuning

Post by ajpturbopittsburgh »

In my other tuning software for my Ford cars and other software suites it seems the norm for idle and part throttle fuel tuning is to force open loop to get your fuel maps or mass transfer functions dialed in. Then when you are less than 5% from your target you switch back to closed loop. I guess this is done to avoid 02 feedback and compensations and corrections so you don't fight with them and isolate the fuel maps.

I thought I read that it is not recommended by hondata to force open loop at idle. Why is this?

I'm going to be retuning very soon for my new turbo and ID1000 injectors so I'm getting some things in order now.

Thanks!
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Hondata
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Re: Forced open loop fuel tuning

Post by Hondata »

It is up to you how you tune idle. I'd recommend leaving closed loop on for most people so they don't foul the plugs straight away if they are a long way off with fuel.
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ajpturbopittsburgh
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Joined: Wed May 26, 2010 10:58 am

Re: Forced open loop fuel tuning

Post by ajpturbopittsburgh »

Ok sounds good...I thought there was something that when u adjust scalars very far from stock in certain cases the ecu can behave unpredictably.

I see in other software there are adjustments for 02 transport delay for people with long tube headers and downpipes for turbos in which you have altered primary 02 sensor placement. This would be due to time of flight for exhaust travel..this would be to sync 02 readings with fuel tables....

Is this something that we may need?
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Hondata
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Re: Forced open loop fuel tuning

Post by Hondata »

Possibly. Really you're adjusting the PID parameters for the closed loop operation; there is no time specific component to the o2 sensor feedback unless you're reconstructing engine conditions at a certain exhaust lambda time stamp for auto tuning.

The other thing I may do is to add the option to use the target lambda tables as compensation tables. That would retain the fuel table as a pure VE table, without the enrichment under load factor added in. Thus you could change the target lambda table and not need to change the fuel table. I notice that VE tables are trendy now, whereas Honda has used them all along (you just need to divide out by the MAP index to get the VE magnitude).
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