Fuel lean out at high rpm
Fuel lean out at high rpm
Hello,
I have some problems with keeping the afr good over 7-8k rpm up to 9k.
Injector duty cycle are way too high
Trying to add fuel but it is even worse,maybe blocking the injectors full open.
B16,CSS block,57mm BW sxe257,Gsc t1 cams/valvetrain,ngk 8
522hp 511nm @ 31 psi on vp c16
The fuel setup is walbro 255 on stock wiring,stock lines,stock fuel filter,stock rail,stock fpr.
I have some problems with keeping the afr good over 7-8k rpm up to 9k.
Injector duty cycle are way too high
Trying to add fuel but it is even worse,maybe blocking the injectors full open.
B16,CSS block,57mm BW sxe257,Gsc t1 cams/valvetrain,ngk 8
522hp 511nm @ 31 psi on vp c16
The fuel setup is walbro 255 on stock wiring,stock lines,stock fuel filter,stock rail,stock fpr.
- Attachments
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- gsc15.s3d
- (231.82 KiB) Downloaded 109 times
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- gsc16.s3d
- (115.45 KiB) Downloaded 114 times
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- CioliGSCfinal522.skl
- (54.74 KiB) Downloaded 114 times
Re: Fuel lean out at high rpm
What injectors are you using?
Re: Fuel lean out at high rpm
Grams 1000cc , sorry i forgot.
I will use a relay and 14v for the pump,this should help i guess and a good fuel pressure regulator with boost reference.
Anything else i should need ?
I will use a relay and 14v for the pump,this should help i guess and a good fuel pressure regulator with boost reference.
Anything else i should need ?
Re: Fuel lean out at high rpm
Is this a return fuel system?
Re: Fuel lean out at high rpm
Sure.stock return style.
Re: Fuel lean out at high rpm
You have a pretty high voltage offset for your wideband (> 1V) - have you confirmed the wideband readings with another wideband, like the one on a dyno? I would recommend you try correcting the wiring issue and get a lower voltage offset. You should also consider moving your wideband to D10 to get the full 0-5V signal.
You have a fuel compensation set up to add a lot of fuel (>10%) at high engine load / open loop based on ECT. My setup is different than yours, but I checked my calibration and I am not adding nearly as much fuel in this compensation as you are.
How confident are you that your dead times are correct?
You have a fuel compensation set up to add a lot of fuel (>10%) at high engine load / open loop based on ECT. My setup is different than yours, but I checked my calibration and I am not adding nearly as much fuel in this compensation as you are.
How confident are you that your dead times are correct?
Re: Fuel lean out at high rpm
I know the voltage setup is not ok but i have installed it the way it should be,ground on the termostat housing,tried battery negative but its the same result.
D14 would not see the full voltage range like d10,but this would not be an issue.
Tried 2 different AEM wideband and it is the same voltage difference.I adjusted the voltage to read like the AEM gauge would and this is how i use it,at least until i solve this thing...
The fuel compensation should be at 0 at hot engine and tune the table.I can do that but i dont think it would make a difference.
Dead times should be correct,they are from Grams website at base fuel pressure.
D14 would not see the full voltage range like d10,but this would not be an issue.
Tried 2 different AEM wideband and it is the same voltage difference.I adjusted the voltage to read like the AEM gauge would and this is how i use it,at least until i solve this thing...
The fuel compensation should be at 0 at hot engine and tune the table.I can do that but i dont think it would make a difference.
Dead times should be correct,they are from Grams website at base fuel pressure.
Re: Fuel lean out at high rpm
Looks to me like your out of fuel. Need all the parts that are still stock. Make a pull and have someone watch the fuel pressure. I guarantee it starts falling off. Seen it many times.
Re: Fuel lean out at high rpm
I've seen many times people use the wrong washer under the fuel banjo fitting which causes this exact behavior.
Hondata
Re: Fuel lean out at high rpm
I have the other fuel rail type,with simple 17mm nut,not the spider washer and 22mm nut.
Meanwhile i have upgraded the fuel rail (FIC) and an6 from the outlet of the fuel filter to rail.
Aeromotive fpr should arrive on Tuesday.I will raise the base fuel pressure,modify the injector dead times and try to go to the dyno at the end of the week.
Meanwhile i have upgraded the fuel rail (FIC) and an6 from the outlet of the fuel filter to rail.
Aeromotive fpr should arrive on Tuesday.I will raise the base fuel pressure,modify the injector dead times and try to go to the dyno at the end of the week.
Re: Fuel lean out at high rpm
Hi,
Went back to dyno few days ealier and made 561hp/535nm at 32psi on Q16 this time.
The fuel problem has been resolved,inj duty cycle is lower now,about 90-100 percent after 8k rpm.It needs a little bit more pressure on the regulator just to stay at max 90percent with injectors but i will fine tune this on the drag strip.
I will upload the datalog from the 32 psi run.
My rpm curve is still not very linear,it is kind of spiky.Is this normal for rpm graph ??? I see that there are the same spikes between rpm and inj duty cycle.Dyno graph looks perfect,no spikes.
Went back to dyno few days ealier and made 561hp/535nm at 32psi on Q16 this time.
The fuel problem has been resolved,inj duty cycle is lower now,about 90-100 percent after 8k rpm.It needs a little bit more pressure on the regulator just to stay at max 90percent with injectors but i will fine tune this on the drag strip.
I will upload the datalog from the 32 psi run.
My rpm curve is still not very linear,it is kind of spiky.Is this normal for rpm graph ??? I see that there are the same spikes between rpm and inj duty cycle.Dyno graph looks perfect,no spikes.
- Attachments
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- datalog4.s3d
- (53.88 KiB) Downloaded 106 times
Re: Fuel lean out at high rpm
RPM should be smooth, this does not look normal.
Re: Fuel lean out at high rpm
What is the specific part number of the spark plugs you are using? Make sure they are a resistor type plug.
Re: Fuel lean out at high rpm
BKR8EIX-11 and BKR9EIX-11
Same results with both.
Same results with both.