FIC 750's scaling and latency issues and THE MEGA FIC 750 thread (hopefully)
 

This is bizzare, but these injectors are acting absolutely weird....

Based on some values I found here on evom

I scaled them to 713 and set latencies as follows (al\lupo values):

3.312
2.04
1.296
0.912
0.792
0.6
0.336

STFT and MTFT were -4.9978 and -0.291399999999999 when idling for about 15 mins

Go out and do a cruise log: STFT and MTFT were -4.9978 and -0.8797

I am excited that I have got them down good. Car idles great, no throttle hang etc...but, read on...

So, I come back home and shut car down. A little while later, I start it up, let her warm up and for shizzles and grins, I decided to log again...

STFT and MTFT were -4.9978 and -6.1744 :crap:

What gives? How does it suddenly change? Not sure what could have happened here...

Dumb question - How does one come up with these latency values? Is it just bumping values up and down or is there a formula to calculate it...

Here is the end-all part I was referring to, I am hoping this thread helps to address all FIC 750 scaling and latencies.....If people are so kind enough to post their values, I will keep adding to this thread...

1) roadspike

Scaled to 696

3.312
2.04
1.296
0.912
0.792
0.6
0.336

2) kreonic

scaled to 650

3.312
1.68
1.032
0.84
0.552
0.456
0.36

3) evoredy

scaled to 665

3.312
1.68
1.2
0.792
0.72
0.456
0.36

4) al\lupo

scaled to 696
also, with 713 scaling he got -0.39% (low) and +0.195% (mid).

3.312
2.04
1.296
0.912
0.792
0.6
0.336

5) John Bradley

Scaling 650

3.312
1.68
1.032
0.84
0.552
0.456
0.36

First you need to drive the car for a significant period of time to really dial in the fuel trims.

Second and more importantly what are you using to log trims? I see you quotoing STFT and MTFT. These are erroneous values used in many OBD2 loggers. You need to look at your Low, Mid, and High trims in evoscan or mitsulogger.

Lastly, your trims can and will be constantly changing. This is what their job is, to change so that you keep a stoichiometric AFR. Trims drift when the engine is warming up, coasting down big hills, recovering from a warm start, etc... Just find a happy medium.

I assumed the engine learned the injectors, figired out the trim and then sorta used this value not having to learn all over again...

I am quoting low and mid in Evoscan...I could swear thats what they say next to those values. My high always stays at .1008.

Thanks, I am learning all this stuff, so I appreciate the tips

SFTF is typically means the short term fuel trim. MTFT typically means main fuel trim.

So, to avoid confusion. What are your Low, Mid, and High values from evoscan.

The short fuel trim in evoscan is the *right now* correction. If it says consistently lean or rich the ecu will change the low, mid, or high trim to reflect the discrepancy. Low trim is for low load situations such as idle, mid is typically for slow speed driving, high is usually updated when cruising on the highway.

All trims change with the weather, type of gas, humidity index etc... They will never be perfect. If you are consistently withing + and - 5% you are very good. I usually only make changes when I'm consistently + or - 10% off or more.

Noob question, I have lots. If I adjust the fuel trims will is effect my fuel maps ? High octane / low octane... essentially will I need to retune ?

713

3.624
2.064
1.512
1.176
0.768
0.624
0.504

Thats awesome to know. Thanks for the explaination. From reading, I was led to believe anything below the 5% band range needed correcting...

Today - I scaled injectors at 731 and will get new latency values.

The low was at -6.xx and mid was at -2.xx if I remember right. High never moved so far, stays at .1008 which is basically 0, right?

So, the ms time, in the latency table, is that the delay before injectors fire at the corresponding delay or how long the injectors fire?

Also, how does the voltage work - why do they have diff values for voltages?

Thanks!

The voltage thing is there because the injectors react at different speeds relative to voltage. The higher the voltage the quicker the injector reacts, and the lower the voltage, the slower the injector opening time. SO, this table helps you dial in the injectors at different voltages, where ~14 is driving range, and ~12 leads into idling range. This is why if your Mid is good and your Low is off you change your 12v latency.

And I think that you're correct with the ms time is the lag time when the injector opens.

My LTFT high never moves also. Does anybodys?

If I were you I'd keep your global the same. Latency changes affect the low trim mostly. Global changes the mid and high trims mostly. Since your mid is fine you will be able to adjust the low a good bit while only making a small change to the mid.

I would subtract 0.1ms to all the numbers in your latency curve and after a couple days I think your low, mid, and high will be very close to 0.

John Bradley (Aaron's) new 750 scaling and latency...

Just tried these out and bumped the 14v latency to .696 and here are the results...

LTFT low: 1%
LTFT mid: -4%
STFT: 5%

Okay guys here are my logs from tonight... just got done logging and thought I would post my results so you guys can actually see the results yourself. Low boost is at 16psi and High boost is at 26psi... FYI I didn't even touch the AFR map one single bit! Once again we have to thank John Bradley for updating his FIC 750 scaling... I adjusted a bit and here are the settings I used...

Scaling 650

4.69v- 3.312
7.03v- 1.680
9.38v- 1.032
11.72v- .864
14.06v- .696
16.41v- .552
18.68v- .360

Good lookin out Fast_Freddie.

hows that mase tune... i know he is really really good with hondas but how is he with ecuflash? i think i may be transferring back to Jax in like 9 months and he tunes at stage 6.... pm me his pricing too...

Fast_Freddie pm sent

FYI - these are the most accurate figures to date that I've seen. I've used these on a few cars and all trims have been within -1 to +2 {thumbup}