Tip in Fuel vs Throttle tip in trim - running rich after each shift

[BabyNSX]

I've been searching for a solution to a problem I appear to be having where my engine starts running really rich after it heats up during heavy acceleration and shifting. I believe this issue is due to the fuel enrichment that occurs during rapid changes to throttle (i.e. when you go from zero to 100% throttle between shifts).

I do have a permanent wide band installed and captured some pulls that show this behavior:
https://photos.app.goo.gl/RGTwNKJYfaGyfFAU7

Note that the each shift if followed by a sharp spike in the injector duty cycle/period and a dip in the AF curve. During these dips in the AF the engine is bogging down and not enjoying things at all.

I played around with the tip in settings ALOT and came up with this:
https://photos.app.goo.gl/pjKZCfQYq7Ni7oUF6

which resulted in the pull looking like this:
https://photos.app.goo.gl/T7j4rDtSitHzbLqo7

The dip in the AF readings are gone, but I'm also seeing that the AF readings are dropping by about 0.5:1 in each next gear (i.e. starting of at about 13:1 in first, then 12.5:1 in second, and finally 12:1 in third). I believe there must be a better way to deal with this issue. Any help will be appreciated.

Cheers,
Doug

[BabyNSX]

I've been searching all over the place for a good description of the differences between Tip in Fuel (TPS tab) vs Throttle tip in trim (Fuel Trim tab), but haven't seen anything posted either on this forum or elsewhere that describes these two similar(?) settings very well and how/when you would adjust one vs the other.

I feel that having a better understanding of these two (knowing that there is some magic happening under the hood of the software - that might prevent a complete description of either) would go a long way to helping me know what direction to take my troubleshooting.

I suspect that the actual tuning is not very gear sensitive, and that the reduction if AF in the higher gears is likely some residual effect of my adjusting the Tip in Fuel parameters so far from their original values... but I can't really know this without some better insights into what the software is doing.

Thanks,
Doug

[BabyNSX]

Can I get some feedback on this issue?

I'd really like to understand what the best approach is to resolving this throttle tip in issue that I'm dealing with. Having two seemingly identical options for attacking this problem without knowing some of the trade-offs for either does not give me a great feeling that I am choosing the best of the two options.

Some clarity into the differences these two adjustments actually make under the hood would be very helpful.

Doug

[Spunkster]

Post the calibration as well as a datalog showing the issue.

[BabyNSX]

Please find files attached.

Thanks in advance for your help with this.

Cheers,
Doug

[Spunkster]

The settings in the TPS section are usually left alone as they are based on coolant temps and should only be tuned by an expert if needed under very unusual situations. You can adjust the setting in the Fuel trim section if your injectors have characteristics that are giving too much or not enough fuel on tip in.

[crluver123]

regarding the AFR reading richer and richer with each gear, that could be based on oil temps increasing, or changes in air temp or coolant temp and having the compensations for those not set correctly.
If the air and coolant temp comps are adjusted accurately enough, then it could simply boil down to ignition timing. when timing is retarded from ideal, the wideband will read on the leaner side. More load on the engine usually requires less timing too, due to higher combustion chamber temps. IE 5th gear requires less timing than 2nd gear. I see in your gear compensations, you have 0 change in ignition timing for all gears. Typically 1st 2nd and 3rd stay at zero, but you want to pull some timing in 4th, and even more in 5th. I usually do -0.75 in 4th and -1.25 or -1.5 in 5th. Or you can also try -0.5 in 3rd, -1.00 in 4th, and -1.5 in fifth.
After testing these settings out, you'll also want to get on a dyno and make sure the ignition timing table is tuned properly for your setup.

[BabyNSX]

Thank you both for your feedback on this.

Spunkster, I'll restore the TPS settings back to default and make further measurements while adjusting the Fuel trim tip in % and see where things end up. I will post my findings. I will hopefully get a chance to visit this on the weekend.

Crluver123, Thanks for the suggestions on gear compensation on my ignition timing, I can see the merit to the suggestions. If restoring my TPS settings and reducing fuel tip in trim doesn't resolve my richening up then I'll see if there maybe any other factors that might contribute to this. So far I wasn't able to see anything in the logs that would have resulted in that, but I could have missed something.

Cheers,
Doug

[BabyNSX]

Well...

I think I was able to "fix" the tip in issue by reducing the trim by about 40%, although I probably could have gone a little lighter this. After doing several pulls to confirm that things were behaving nicely, I experienced the same issue that caused me to dive into this problem in the first case. Namely, that when I go through the gears the engine riches up significantly and bogs down.

Once this issue started up again it was rather persistent so I was able to get a clean data log while this was occurring and figured I would share it here to see if someone could pick apart what might be happening.

The two logs attached show what I think is a reasonable pull where the engine keeps itself in a good state during the pulls, while another pull shows the richening up issue. There is no difference between the tune between the two pulls, just about 10mins of driving. I've attached the tune that was used.

History of the issue:

- This issue seems to only appear after the engine has been running for 20+ minutes (i.e. warmed up completely).
- I never seem to experience anything unusual when driving around town.
- The issue seems to only show up after doing a full throttle pull when going up the gears. It seems to only show up after the first shift (i.e. first gear seems fine, and then 2nd goes rich).

- I have changed the FPR recently to try and resolve this issue. The thought was that the FPR was "sticking" and causing a fuel pressure surge in the rail. Clearly the FRP is not the issue. I do not have a cabin mounted fuel pressure gauge, but perhaps that will be necessary to continue investigating this.

- Could there be some issue with the fuel injectors that might be causing this (i.e. could one of them be getting stuck open? and if so, why would the engine continue to run normally when I kill the throttle).

Any help with this would be very appreciated.

Thanks,
Doug