Derex'7

iTrader: (16)

Okay I'm seeking some guidance here.

My setup includes the following:

Streetported
KG parts R85 Single turbo setup
RW 90mm TB
GM 3bar Map sensor
HKS ign amp
750/1680
Aeromotive FPR
HFP 255LPH Fuel pump
-6 Lines

My idle is fine and my TB voltage (VTA1 & VTA2) are setup within specified range.

What I can't seem to fix is the severe lean hesitation/bucking I have at low loads. (Moving from a dead stop or decel slow and then trying to accel really fast) I've played with everything and only thing that seems to help out somehwat is when I increase the primary injector lag.

Now I read Argxh thread on the Accel table but still didnt really get a good understanding of what exactly the "V/T" table in Accel vs TPS1 means. I understand the setting part and that is amount of fuel % wise to add.

1.500=105%

I dunno, I just really need some guidance here, hopefully someone has an identical setup who has had success smoothing out there low load bucking.

The lean spikes are driving me mad and make the car, a nuisance to drive

Derex'7

iTrader: (16)

ok I think I may have found the problem, seems I have a ton of play on my throttle adjustment cable

ttmott

iTrader: (1)

Can you check AFR? Sounds more like a lean condition at tip in and/or in the low load areas of the map. Your tip in enrichment may not be the essence of issue if the map in those load areas are lean however.

A loose cable is unlikely but I hope the fix is that easy.

Derex'7

iTrader: (16)

haha yeah that definately was not the fix, yeah its a really bad lean spike my afr pegs out at 19.1 AFR

Derex'7

iTrader: (16)

So I need to datalog initial throttle response from a dead stop and add fuel to those cells I'm spiking in...

cewrx7r1

iTrader: (2)

Do not forget the two accelerataion control tables, and the inj vs tps table.
All three can be used for your problem to add more fuel.

arghx

iTrader: (3)

the tuning group has a writeup on how to set up charts for these logs. Look at "Diagnosing tip-in problems" in the "Logging Scenarios" table in the chart setup walkthrough available in the files section.

"V/T" has to do with the rate of change of TPS voltage. It is how fast the throttle is moving. So if I am 1 volt of TPS and a second later I'm at 2 volts, well my V/T is lower than if I start at 1 volt and get to 4 volts a second later. Unfortunately there is no way to directly log "V/T" in the Datalogit software.

You can try copying my numbers from that thread https://www.rx7club.com/power-fc-forum-47/accel-settings-inj-vs-accel-tps1-eliminate-stumbles-916169/ into your map. It might be a decent starting point.

Derex'7

iTrader: (16)

yeah I lowered the V/T value to .078 and added like .90 but didnt seem to do much of anything. I also increased the Accel inj table as well.

I'm goint to try and lower the bottom value in the "INJ vs TPS" table and increase fuel/ms in the N1-N3 columns in my map.

Do I need to try and further lower the V/T value?

ttmott

iTrader: (1)

The appropriate tactic is to first get the AFR's correct at steady state cruise then attack the throttle enrichment features.

Maybe you are already OK at steady state cruise but it's unclear in the posts.

ttmott

iTrader: (1)

What I have done to understand this is paste the time and voltage relative to other parameters of interest into Excel from the datalogit data file. Through some simple math the accelleration can reveal it's self in deltaV/deltaT in chart format. Consequently, one can see the results of changes to the tip in tables.

Derex'7

iTrader: (16)

Yeah Im okay at cruise with anything under 3k after that she goes hella rich...she idles fine but not nice and smooth can def hear the timing is off...

Could this lean tip in be a timing problem? More or less advance

ttmott

iTrader: (1)

First did you remove the three wires (see Dale's posts) from the ECU connectors?

Sounds to me like the approach on the tune is rather backwards. Do you have the FB controls turned off? They must be off for initial tuning.

Make sure the engine mechanicals are baselined and in calibrated working order (TPS voltage, TB set up correctly, MAP calibrated, sensors working correctly).

Next get through the Idle learn

Then attack the fuel map and get your AFR's correct throughout the map.
Chuck has his tuning notes available in the workgroup and they are essential to do this right. The workgroup also has some Excel tools to support fuel tuning that are invaluable.

Once you have the above in order then attack all of the "trim" features (tip in, cold start, ign timing, boost, etc, etc).

After all that work its time to clean up the idle which is back to the fuel map and it's idle zones.

All the above is an iterative process; make a small change then run the car and log results, make another change then run the car and log results again.

I have found once somewhat of a basis is found gross changes are not appropriate, only small adjustments one at a time are. Also note that a change can and will affect other parameters so logging is the key to understanding.