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[FreshDA9]

have noticed when tuning some vehicles when i de-cell from a pull or coming to a stop light the car will shut off. is there any tips or tricks to help with this from happening.

attached is a photo below 30kpa in which i assume we should add more fuel to correct this? should we also add more timing in these areas? (this is just a starter map loaded)












And to make up for the Faildata screen shot!

[Minor Threat]

What are your idle AFRS/timing like?

Is your IACV functioning? What's the duty cycle set at? If you have a working IACV try bumping up the duty cycle, I've found this helps. Not sure if it's because the default setting puts the IACV at too "low" of a position to catch the RPMs when they're falling rapidly, but it's cured the problem a lot of the time for me.

I would also double check your base timing/cam timing, if it's way too low that will cause it to not to catch itself as well. You can also try bumping up the timing in the cells below the idle rpm by a few degrees.

[FreshDA9]

Idle AFR's i tend to run 14.3-15 depending on injector. Timing in the cells between 16-20. Base timing is always done to 16 degrees.

I have been getting a lot without IACV's lately. The last car had an IACV and i did up the duty cycle and still wouldn't catch. I started playing with timing and fuel in the De-Cell areas and it would catch but wanted to see what people are doing for these issues. I don't see any harm in what im doing but it doesn't hurt to ask. I remember someone saying the first thing they did was add 20% to the de-cell area when they started a tune. 

[PhilStubbs]

I get popping on shifts when adding to much fuel in that area. Usually an iacv bump will fix it when I have that problem. Might need to bump the idle bleed screw if the car doesn't have an iacv. I make people live with a higher idle when they are too lazy to fix/plumb one in.

[DSharp]

Think of the red line as a plot of your engine rpm vs map with the throttle closed, obviously not accurately drawn.  Notice the shape.  Low rpm = less vacuum and eventually  0 rpm = 1 atm.   You might want to adjust parts of the map often overlooked. 

[FreshDA9]

Yea i adjust those areas mainly for cranking. never really thought of it being an issue with de-cell since i never see my cursor head that way while logging?

[DSharp]

When you say decel are you in gear? 

Idle recovery might touch cells you don't expect, especially if it doesn't recover and shuts off.

[PhilStubbs]

That area has nothing to do with cranking. Plus there are crank settings along with post crank.

Decel in gear will get vac levels you will never see otherwise for sure

[FreshDA9]

When you say decel are you in gear? 

Idle recovery might touch cells you don't expect, especially if it doesn't recover and shuts off.

No when im done with the pull on the dyno you have to put it in neutral. then it drops off and shuts off like you say.

PhilStubbs- I have made changes in that part of the table with success (did this trying to diagnose a starting problem once), I have also used the post crank table under the fuel parameters.  But like i said im not having issues starting a car.

[PhilStubbs]

Even in neutral from such a high rpm, I'd guess you would see more than 20inhg. I didn't realize the issue was dyno pulls.

[92CXyD]

Inj. offset vs. voltage?

What is the Alt voltage look like at low revs? 

[DSharp]

can you post data log and calibration?

[Joseph Davis]

For not-Hondata the TB needs to be open enough to idle 100-150 below lowest target with the IACV unplugged.

For Hondata, the IACV control has been rewritten, and you slide the slider bar and it works.  Except for the cars where it doesn't work, and the idle is just wonky.  Go Hondata!

[PhilStubbs]

Neptune is the only software that has had a working slider for idle for me everytime. Hondata and Crome both have their times where the idle duty cycle does nothing at all. I have always wondered what causes that.