Like the title states. I have a good idle in park or neutral. when I go into any gear. Reverse, drive, 1, 2, 3. The idle goes down to around 500 and is extremly rough, not uncommon for it to stall. i can play with it and finally bring the idle back up. I know there are still problems with the tune. what i dont understand is why its doing this. i've searched and searched and cannot solve my problem. any help is appreciated. The mods are mostly unknown. supposedly a stall and few other transmission upgrades. not sure if that matters. motor has a cam and head work ect. i know iac's are not where they should be. i have played with them all over the place with no help.
I attached several logs trying to capture this problem. afr never changes. however watching the wideband it will go lean after a while of experiencing this problem. once it goes lean i can swap it back into neutral or park and itll rev up to around 2k rpms. It'll finally settle back down after several seconds. also attached the current tune.
Your VE table is definitely going to cause problems. Please post a copy of the Stock GM file for your motor and list
your mods and I will see if I can help you out.
James, im mot thinking its the ve table. I have made adjustments that dont change the idle at all. Its like im missing something else. My afr are spot on until I swap into gear then my idle drops way down and struggles to recover. I can post a stock file and whille shortly
Also noticed this morning the idle drops when I push in the breaks sometimes. I know there are no vaccum leaks. I can unhook the break booster and plug the line to the intake and the idle still drops and gets rough. Maybe like a tcc switch or something? Need opinions.
I have heard of TCC switch on Dodge trucks that will do that if the transmission is not completely full of fluid to the full mark or slightly above.
In that case, if we put the truck in neutral before coming to a stop, the motor would not die because the TCC would not try to lock up. After
we filled the transmission slightly over the full mark it solved the problem.
I just think your VEs look so bad that you could be operating in a different part of the curve in gear than out of gear due to increased MAP
in gear could have a VE value to high, too rich. I configure a histogram filter that requires wheel acceleration/decal to be <10 counts and
throttle position TPS to be >0.4%. This way, like you said, there are no readings when coasting, and there are no readings when you
are accelerating or decelerating, since 10 counts either accel or decel is pretty much same as steady state.
I would also throw out any cells without at least 10 hits and any cells that have correction factor over 10%, or at least correct them by only
5% since outlier indicate erroneous readings. Steady state readings are of course more difficult to achieve under 1600 RPM anyway because
the signal is based on a less dense exhaust gas that is more prone to error.
Last edited by JamesLinder; 08-29-2014 at 01:37 PM.
I see what you're saying. I have adjusted my ve tables countless times to try to cure the problem though. I adjust in the upper range of my ve tables. You can see where ive richened it up considerably. Since I see it on the wideband eventually go lean aftet several seconds of this problem occuring. My ve tables are not too bad and it stays right around where I want it. Ill try leaning out that part of my ve's. Maybe I will see a change.
is this when you are just starting up the motor. if that is the case your your "cat lightoff startup spark correction" table
may be the culprit. Multiply the "multiplier" for that table by 0.5 so it will halve the values when starting up. I also
find that if you have removed the EGR then you should zero out the "EGR Spark Advancement Spark Correction" table.
I did zero the egr table. this motor has no emissions on it. it doesn't only do it on startup. it does it anytime I reach 0 mph in drive or reverse with the brakes pushed in.
I would say its a combination of your MAF and VE tables being out of calibration so that you are either
way lean or way rich at idle. Tell me about how you installed the wide band; where is it located
and have you turned off open loop and fuel trims for tuning purposes?
If the car is not stock then the MAF calibration will need to be increased between 7% and 12% across the board depending
on how much you opened up the inlet air intake system. If the car has a cam then the VE's for 400 through 1200 RPM should
be decreased about 15% to 20% at all MAP values. These are just to get you in the ball park, and you will have to log
lambda error at open loop without fuel trims to calibrate your MAF and VE's. It is not possible to guess your way to a
good tune. The WB oxygen sensor must be installed in one of the bungs in your exhaust where your secondary OEM
sensors were before. You have to disable MAF to tune VEs, and disable VE's to tune your MAF. You must ignore readings
when accelerating and decelerating and when throttle is closed so that you are not getting non-steady-state data readings.
If the car is not stock then the MAF calibration will need to be increased between 7% and 12% across the board depending
on much you opened up the inlet air intake system. If the car has a cam then the VE's for 400 through 1200 RPM should
be decreased about 15% to 20% at all MAP values. These are just to get you in the ball park, and you will have to log
lambda error at open loop without fuel trims to calibrate your MAF and VE's. It is not possible to guess your way to a
good tune. The WB oxygen sensor must be installed in one of the bungs in your exhaust where your secondary OEM
sensors were before. You have to disable MAF to tune VEs, and disable VE's to tune your MAF. You must ignore readings
when accelerating and decelerating and when throttle is closed so that you are not getting non-steady-state data readings.
ok, I have worked on the tune more. It still does the idle problem. the afr bounces from 14.0 to 14.4 and timing ranges from -4 to +4 while it does this. idle while coasting stays 22 degrees and holds perfect idle until the vss reaches 0. then the timing goes crazy and so does the idle. still cant figure it out. help!
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