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ECMlink Throttle tip in lean from idle

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Jacob_Barnes520GST

5+ Year Contributor
100
8
Feb 21, 2018
Tucson, Arizona
I'm having a hard time with throttle tip in. Whenever I step on the gas pedal from a 0% throttle position, I lean out badly for a second then it returns to normal AFR. I adjusted the BaseTipInTPSAdj in direct access and didn't help anything. I'm stumped if anyone can help I'd appreciate it. I will attach a log below.
 

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  • log.2020.07.22-01.elg
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Your log "looks" a little rich. Your computer is pulling 12-16% fuel from the mix according to your Combined FT at idle. Maybe the "bog" you have is from being too rich. If you have the courage (you can always change this back), change your global to -50, save to ECU, and see if your CFT gets closer to zero. You may think it is to lean when you touch the gas but "maybe" its just too rich. Just a comment/suggestion.
 
There is also one other thing, try reducing your deadtime (leave global alone) and watch your Combined FT. I would start lowering it (deadtime) and see if the CFT gets closer to zero. It will adjust your STFT at the same time.
 
Admittedly, I did not look at your log, but “tip in” is a term that’s thrown around all too frequently. 9/10 tunes hesitate, stutter, bog, spike, etc. from the fuel and airflow being scaled out of proportion, not from a tip in setting. People regularly ask me to look at their tune cause they can’t get the “tip in” to act right. It’s usually the ve table having large jumps between cells or the wrong injector data and having a scenario of, in an exaggerated sense, “ twice the injector size half the VE” cause it yields the afr you want.
 
I generally find that getting airflowperrev and fuel trims in check usually yields the best results. I have had the intention of writing a post explaining the basics of tuning for quite some time. I know there have been hundreds of posts but I firmly believe in understanding why you’re making the changes you make to the tune rather than what changes to make. Until I take the time to sit down and explain it, I recommend finding Kevin jewer’s account on the link forums and reading all of his posts. In the years I’ve been tuning I haven’t found anyone else who is willing to explain things to the extent he does, including the logic behind his methods.
 
I have thought as well about. Sometimes what you think the car wants by looking at the wide band when car is in closed loop will steer you wrong and it may confuse new people.
 
I generally find that getting airflowperrev and fuel trims in check usually yields the best results. I have had the intention of writing a post explaining the basics of tuning for quite some time. I know there have been hundreds of posts but I firmly believe in understanding why you’re making the changes you make to the tune rather than what changes to make. Until I take the time to sit down and explain it, I recommend finding Kevin jewer’s account on the link forums and reading all of his posts. In the years I’ve been tuning I haven’t found anyone else who is willing to explain things to the extent he does, including the logic behind his methods.
WELL SAID!!! The only one to explain WHY! A super person to follow and read his post's, they are really invaluable.
 
Heys guys, I'm really liking this thread as I am having the exact same issue. I feel things are dialled in but then I have tip in, or free rev bog that i suspect is a rich bog. Jacob, are you speed density or MAF?

I guess I have never reviewed someone else's log, can I add in their map and wideband as they are light gray when I view his log.
 
I am running a stock 2g maf, not on speed density. I will post up another log when I'm at work. I know it's a lean stumble-because the wideband will read anywhere from 16.8-22.0 when I press on the gas initially. Once it starts to move it corrects back to ~14.7.
 
A stumble on tip-in does sound like there might be an issue in the tune, but the lean reading I would argue is always going to happen to some degree. I'm certain there are ways to minimize tip-in lean and tip-out rich, but I feel like it should be stated that it can't be entirely eliminated when using a cable driven throttle body. When you go from closed to open, you have atmospheric pressure rushing into a vacuum (The velocity of air at atmospheric pressure rushing into a vacuum can reach nearly supersonic speeds depending on the volume of vacuum being displaced) which will drastically increase the volume of oxygen entering the combustion chamber. I don't think our ECUs run fast enough to react to any sensors and adjust before air and fuel have entered the combustion chamber.

Engineering Explained posted a video where he talks about rev hang, but in the video he explains the problems with mechanical throttle bodies regarding tip-in lean and tip-out rich, also how they have a non-linear torque vs throttle position. Pretty interesting in my opinion.
 
Saw the sliders myself but since they started at 2k, I didn't mention them. Good eye tho Tony!!!
 
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