open loop SD running away lean
Thread Starter
Teching In
Joined: Apr 2022
Posts: 29
Likes: 10
open loop SD running away lean hello everyone im having a issue that seems like it happend out of no where i keep going lean on my ve on idle and partial throttle ,i allready swapped to another set of injectors that i had flowed and cleaned ,new plugs new fuel filter ,cleaned tank and all lines ,new tr6 plugs even swapped to another pcm .but issue persist , my ve table is in the 70s in the idle area but still pegging my wideband lean , if i raise the ve it will be in a decent 15.0 afr for only a few min or hours and then bam its lean again! truck was running strong on 8lbs of boost for a solid month and then this happened wich lead me to do all these repairs but i feel im missing something here ,any help is appreciated
p.s its llike the pcm isnt listining to the ve table and is refrencing another table ..
setup is: gen4 5.3, pac1218s,ss2 cam ,7675 on8psi ,80lbrs,4l80, 60 psi base with rising rate hooked up
p.s its llike the pcm isnt listining to the ve table and is refrencing another table ..
setup is: gen4 5.3, pac1218s,ss2 cam ,7675 on8psi ,80lbrs,4l80, 60 psi base with rising rate hooked up
Just looking at that file I don't even know where to start, I have a hard time believing it was fine for month and it started going this stuff out of the blue but maybe it's from weather changes because things are disabled and just plain not correct.
- Complex Model for Cylinder Charge Temperature disabled
- Cylinder Charge Temperature Bias table just flattened to 1.0
- You should not be anywhere near 200 in the VE table at only 8 psi of boost
- Running speed density open loop is a recipe for disaster on a Gen3 PCM
- 80 lb/hr injectors, which ones? Only 80s that I know of are Siemens Dekas which are dirty and inconsistent as hell
- Transient min fuel milligrams table untouched
- Your transient evap and gain fuel tables look really weird to me, don't have your stock file to reference but were those changed for some reason?
- Timing table needs some serious work but that's not causing your weird fueling
- Complex Model for Cylinder Charge Temperature disabled
- Cylinder Charge Temperature Bias table just flattened to 1.0
- You should not be anywhere near 200 in the VE table at only 8 psi of boost
- Running speed density open loop is a recipe for disaster on a Gen3 PCM
- 80 lb/hr injectors, which ones? Only 80s that I know of are Siemens Dekas which are dirty and inconsistent as hell
- Transient min fuel milligrams table untouched
- Your transient evap and gain fuel tables look really weird to me, don't have your stock file to reference but were those changed for some reason?
- Timing table needs some serious work but that's not causing your weird fueling
Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
Finally got around to viewing the tune.
Besides what was pointed out above, I noticed that the VE table in 3D view looks like a pile of rough rocks instead of a very smooth landscape. What that means is that a tiny change in kPa or RPM will result in a big change in fueling (AFR) instead of a tiny change.
The mentioned "Complex Model for Cylinder Charge Temperature disabled" is related to the location of the IAT sensor. If it is located in the intake manifold after the SC and any intercoolers, then it might best be disabled. However, if the IAT is before the SC, then it must be enabled or all fuel tuning will be way off.
As mentioned the Spark table is very unusual and just not right.
Also notice the Throttle Cracker is disabled, which could lead to stalling issues.
Besides what was pointed out above, I noticed that the VE table in 3D view looks like a pile of rough rocks instead of a very smooth landscape. What that means is that a tiny change in kPa or RPM will result in a big change in fueling (AFR) instead of a tiny change.
The mentioned "Complex Model for Cylinder Charge Temperature disabled" is related to the location of the IAT sensor. If it is located in the intake manifold after the SC and any intercoolers, then it might best be disabled. However, if the IAT is before the SC, then it must be enabled or all fuel tuning will be way off.
As mentioned the Spark table is very unusual and just not right.
Also notice the Throttle Cracker is disabled, which could lead to stalling issues.
The mentioned "Complex Model for Cylinder Charge Temperature disabled" is related to the location of the IAT sensor. If it is located in the intake manifold after the SC and any intercoolers, then it might best be disabled. However, if the IAT is before the SC, then it must be enabled or all fuel tuning will be way off.
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Moderator
Joined: Aug 2010
Posts: 7,323
Likes: 529
From: Ann Arbor, MI
It has nothing to do with the IATs location and everything to do with how cylinder charge temperature is modeled, yes I know what the description says in HP Tuners but I don't agree. It was an enhancement introduced in the 01+ operating systems and the engine coolant temperature still has a very real impact regardless of the IAT's location with forced induction. Any time I've disabled it I can watch fueling move around more than leaving it enabled.
Do you have any ideas on what this "model" is actually doing then? And how the IAT and engine temperature affect the fueling? I suspect that on any boosted engine the IAT should be in the intake manifold as this is the actual "charge" temperature.
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Teching In
Joined: Apr 2022
Posts: 29
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thanks for the reply guys wanted to update the thread with the issue , when i swapped to a new pcm the egr airflow tables wherent zeroed out, in hinesight evertime i would power on the wideband the truck would act dramatically diffrent, and yes that map is a mess since i have been for weeks making changes on it and it would keep needing to get adjusted after only a few minutes of use , now that i found that i was able to use my actual map from a month ago and the ve looks sane now ..yes as u can see in that map ,i tried changing everthing until a convo with a buddy gave me the eppiphany
