Richer Idle?
Richer Idle? Quick description of the car is LS 347 H/C/I on a SD tune. Car has been running great for years until now. The car will start and idle fine but the problem is when it goes into closed loop the idle richens up??(13.8-14.2) Also it stalls everytime I try to put it in gear(4L60E) and when trying to restart the car it needs help. Never had the stalling problem untill the richer idle. I dont have any codes and no tuning software to do any data logging. Im thinking O2 sensors but really dont wanna spend the money on them if its not the problem. Any more info needed just ask. Thanks!
Checked the MAP, checked line going to brake booster, and checked bolts to intake for tightness, all seem good. Im really thinking about going ahead and getting the tuning software. What would I look for if the 02 are going out?
Get the fuel trims from the o2 sensors. You don't even need a full tuning software, unless you plan on tuning the car yourself. All you really need is some sort of obd2 scanner, like a dashhawk or if you have a smartphone they have some apps to scan the engine through a bluetooth obd2 connector.
This sounds like mistrimming, cold weather is worse on
O2 sensor performance especially if there's headers.
You might want to force open loop idle ("PE trick") if
your O2s don't last.
O2 sensor performance especially if there's headers.
You might want to force open loop idle ("PE trick") if
your O2s don't last.
Well theres no telling how old these current o2s are. They have been in the car for a couple years and they came with the harness I bought off a wrecked car that had been sitting for awhile!
Now that I think of it, I started having this problem once the weather started to get colder here in Georgia and yes Im running long tubes.
Now that I think of it, I started having this problem once the weather started to get colder here in Georgia and yes Im running long tubes.
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Joined: Apr 2011
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Quick description of the car is LS 347 H/C/I on a SD tune. Car has been running great for years until now. The car will start and idle fine but the problem is when it goes into closed loop the idle richens up??(13.8-14.2) Also it stalls everytime I try to put it in gear(4L60E) and when trying to restart the car it needs help. Never had the stalling problem untill the richer idle. I dont have any codes and no tuning software to do any data logging. Im thinking O2 sensors but really dont wanna spend the money on them if its not the problem. Any more info needed just ask. Thanks!
I can tell you that's how the car is tuned from the factory. There isn't anything wrong with the process of steps you described.
Open Loop EQ Ratio: Your vehicle runs rich (Stock '98 LS1 range of 8.75-14.62 AFR) depending on the engine temp. to get the car warmed up.
Then when the car reaches a predefined temp. (Stock '98 LS1 range of 93-141*) for closed loop operation to begin.
Closed Loop: At this point the 02's take over and they make subtle adjustments which are called STFT (Short Term Fuel Trims) which are temporary adjustments which then update to what are called LTFT (Long Term Fuel Trims) which are then saved in your computer for the next start up. The entire time the STFT updating to the LTFT are the car learning how much fuel adjustment (addition or subraction) from the existing tune to hit the target stoich value provided in your tune as a final closed loop operation target (Stock '98 LS1 is 14.68'ish AFR).
What you described COULD be an issue as I have no way to tell what you tune is setup for. But based on what you have described the vehicle is doing what it is supposed to do. Even on a modified tune.
I would personally assume your tuner needs to visit Hp Tuner Forum and search "Idle Tuning Walk Thru" using Hp Tuners to get your IN GEAR (reverse) issue fixed.
Okay, I was able to get a hold of a Diablo Sport Predator and do some ghetto data logging. I dont have any graphs to post, just numbers to go off of.
I wasnt able to read the fuel trims and o2s at the same time so this may help or not. The STFT from bank 1 and 2 seemed to almost follow each other and values were as high as -25.0 to as low as -1.0, they never went positive and constantly changing from high to low. Went to -35.0 once! The LTFT Im assuming are disabled because the always read 0.
Now the front o2 sensors(no rear o2s) also seemed to some what follow each other and ranged from 820-35(mV) constantly going up and down in value and went to 0 a couple of times. This was all taken at idle with a ECT between 180-190.
I wasnt able to read the fuel trims and o2s at the same time so this may help or not. The STFT from bank 1 and 2 seemed to almost follow each other and values were as high as -25.0 to as low as -1.0, they never went positive and constantly changing from high to low. Went to -35.0 once! The LTFT Im assuming are disabled because the always read 0.
Now the front o2 sensors(no rear o2s) also seemed to some what follow each other and ranged from 820-35(mV) constantly going up and down in value and went to 0 a couple of times. This was all taken at idle with a ECT between 180-190.
Just a quick update. The car decided to run fine today without any changes. Still occasionally dipped in idle when putting in gear but no stalling. Soon I hope to have HPTuners and Ill be back for help trying to cure the going into gear problem and the open loop idle("PE trick") that jimmyblue mentioned. Thanks for all the help and responses fellas!
