Big overall fuel trim adjustment after changing big cc/min injector

K-Series Programmable ECU installation questions / support issues
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CHB
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Big overall fuel trim adjustment after changing big cc/min injector

Post by CHB » Sat May 05, 2018 7:16 am

Hi Hondata,

I just replaced the some 1000cc/min injectors (Bosch 14mm High Impedence 12ohm). Before I did the change, I warmed up the car and A/F was steady at 14.5AFR at idle.

Changed the injectors, changed the injector size value in kManager to 1000cc, and also changed the injector dead time table accordingly.

The car started straight up with no hesitation, in fact it started better than the stock keihin 270cc injectors, but.... AFR was around 25AFR.

I have to adjust "Overall fuel trim" to +75%, only then the idle AFR will be at 14.5-15.0 AFR.

I'm using Kpro4 in PND on K20A3 DC5, using stock PND Air Fuel Ratio Sensor.

Does this seems correct?

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Re: Big overall fuel trim adjustment after changing big cc/min injector

Post by Hondata » Sat May 05, 2018 2:08 pm

What dead time values did you use? What fuel pressure are you running? I think some of the 1000cc injectors are around 850cc/min unless you are at very high fuel pressure.
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Re: Big overall fuel trim adjustment after changing big cc/min injector

Post by CHB » Mon May 07, 2018 7:42 pm

I have not installed fuel pressure gauge, and still on stock fuel pump.

The injector is Raceworks (Australian brand) which uses Bosch injector core.

Attached is the dead time setup from the manufacturer. I've entered the values on 43.5psi (3bar).
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CHB
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Re: Big overall fuel trim adjustment after changing big cc/min injector

Post by CHB » Mon May 07, 2018 7:56 pm

Just to add on, these injectors have been tested flowing 1000cc @ 43.5psi 3bar.

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Re: Big overall fuel trim adjustment after changing big cc/min injector

Post by Hondata » Tue May 08, 2018 5:48 am

What sort of injector are they? If they are the Bosch EV6 or EV14 then the dead time at 14V is going to be around 1.2ms, not 0.88ms
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Re: Big overall fuel trim adjustment after changing big cc/min injector

Post by CHB » Fri May 11, 2018 8:40 am

They are EV14
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Re: Big overall fuel trim adjustment after changing big cc/min injector

Post by Hondata » Fri May 11, 2018 9:15 am

Dead times are going to be around 1.2ms @ 14V
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Re: Big overall fuel trim adjustment after changing big cc/min injector

Post by CHB » Sun May 13, 2018 9:21 pm

I've used the default ID1000 table and fire it up, works great.. idle dead stable at 13.8-14.0AFR with 0% overall fuel trim.

Thanks Hondata.

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