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Author Topic: How to fix high short term fuel trim under boost.  (Read 986 times)
bombis
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« on: March 21, 2024, 07:55:08 AM »

Bosch 550cc, garrett gt28rs   

Hi. This is my first modded bin.

Adjusted krkte(fuel) up 3% and kfkhfm(maf correction) to 1

Made a logfile, see new post
« Last Edit: March 22, 2024, 12:50:24 PM by bombis » Logged
_nameless
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« Reply #1 on: March 21, 2024, 08:28:27 AM »

EngineSpeed   BoostPressureActual   LambdaControlAvg   AirFuelRatioDesired   AirFuelRatioCurrent   
 3360                           2208.55                 1.02301                 0.825929                  0.983644                                                                  
 3440                           2247.34                 1.12677                   0.829347                   0.897706   

PartNumber  = 4B0906018DC
Bosch 550cc, garret gt28rs   

Hi. This is my first modded bin.
I can see current AFR is highter than requested afr. Do i need to adjust some maps to make them more similar?

Here we go again............. No data logs, and posted in the wrong section. Running that lean you will melt something quick, I wouldn't continue to hammer on it. Now that I got that out of the way...... It could be a million things from poorly calibrated injectors, shitty quality fake china knock off injectors that will lockup with a rising rate fuel system, plugged fuel filter, weak fuel pump would be my starting point. Changing calibrations before vetting hardware is never a good idea. 
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bombis
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« Reply #2 on: March 21, 2024, 09:49:37 AM »



.
« Last Edit: March 21, 2024, 11:20:34 AM by bombis » Logged
bombis
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« Reply #3 on: March 21, 2024, 11:20:10 AM »

Here we go again............. No data logs, and posted in the wrong section. Running that lean you will melt something quick, I wouldn't continue to hammer on it. Now that I got that out of the way...... It could be a million things from poorly calibrated injectors, shitty quality fake china knock off injectors that will lockup with a rising rate fuel system, plugged fuel filter, weak fuel pump would be my starting point. Changing calibrations before vetting hardware is never a good idea. 
Got brand new Bosch 550cc original injectors
Fuel filter 2-3 years old
Walbro gss 341 fuelpump
Original atw fuel pressure regulator
wideband lambda from innovate LC-1. Not sure if its ok to use this one
temporary i vent DV to atm
krkte 0.05153

KFKHFM original;
idle 1.01, hi rpm 1.08
I want to set this map to 1. Thats richer right?
And/Or set krkte highter
« Last Edit: March 22, 2024, 12:46:32 PM by bombis » Logged
bombis
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« Reply #4 on: March 22, 2024, 04:56:01 AM »

short term fuel trim looks ok with low boost
« Last Edit: March 22, 2024, 12:51:42 PM by bombis » Logged
bombis
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« Reply #5 on: March 22, 2024, 11:28:50 AM »

Frm_w short term fuel trim, gets high under boost.
How to adjust?
« Last Edit: March 22, 2024, 12:49:54 PM by bombis » Logged
James1
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« Reply #6 on: March 22, 2024, 01:32:25 PM »

You need to add more fuel in that area - what determines the amount of fuel injected, and what corrects it? These are very basic fundamentals, you must know them before you can start tuning.
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bombis
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« Reply #7 on: March 22, 2024, 02:24:23 PM »

You need to add more fuel in that area - what determines the amount of fuel injected, and what corrects it? These are very basic fundamentals, you must know them before you can start tuning.
KRKTE is very important. This will add fuel everywhere, but i only want it on hi rpm/load
i havent tried KFLF, but I will try tomorrow Smiley
 
« Last Edit: March 22, 2024, 04:01:28 PM by bombis » Logged
prj
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« Reply #8 on: March 22, 2024, 02:30:03 PM »

I only know KFKHFM for adjustments within a range.
Is that ok, or do you have other maps in mind?

KFKHFM adjusts load not fuel.

Start by reading the wiki instead of posting.
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Jozua
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« Reply #9 on: March 23, 2024, 12:00:51 AM »

Also had similar problem arent you burning some oil how oil consumption
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bombis
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« Reply #10 on: March 23, 2024, 08:56:44 AM »

Also had similar problem arent you burning some oil how oil consumption
Haven't noticed any oil consumption
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bombis
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« Reply #11 on: March 23, 2024, 09:00:23 AM »

KFKHFM adjusts load not fuel.

Start by reading the wiki instead of posting.
I adjusted KFLF map up to 1.3x at high load. Runs so much better now Cheesy
« Last Edit: March 23, 2024, 11:52:01 AM by bombis » Logged
ratosluaf
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« Reply #12 on: March 23, 2024, 03:50:23 PM »

you fucked up something really bad if you need to correct your fuel by 130%
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_nameless
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« Reply #13 on: March 23, 2024, 08:50:29 PM »

you fucked up something really bad if you need to correct your fuel by 130%
That would be a 30% change 1= no change, more than 1 is more fuel. 2.3 would be 130%.
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bombis
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« Reply #14 on: March 31, 2024, 02:49:37 AM »

you fucked up something really bad if you need to correct your fuel by 130%
Yeah you're right, it was too much. I¨ve spent the weekend adjusting KFLF. 1.15 or +15% runs very well Cheesy

MAF stops at 222g/s at 4800 rpm
Is it ok to go at higher rpms as long as fuel/knock is ok?

I¨ve ordered bigger MAF housing to get better flow/readings Cheesy
« Last Edit: March 31, 2024, 01:38:12 PM by bombis » Logged
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