Can we discuss MTEISF, MTEFTC, etc?

Covers all sn94/95 mustang v8 ecu's.
DOHCTOR_32V
Posts: 79
Joined: 2021 Apr 24, 12:07
Location: USA
Vehicle Information: 95 Cobra

Can we discuss MTEISF, MTEFTC, etc?

Unread post by DOHCTOR_32V »

Hello. I'd like to gain some understanding of these particular functions, scalars and tables. Would anyone one mind a discussion concerning the relationships of MTEFTC, FN312S, FN313, FN1322AL, FN1323A, FN1322DL, FN1323D and MTEISF, FN1321?

I understand what MTEISF and MTEFTC are multipliers of.

In layman's terms, how are the functions and tables used for throttle response and performance gains?

Thanks!
wwhite
Posts: 313
Joined: 2021 Feb 16, 15:53
Location: Victoria, BC, Canada
Vehicle Information: 1994 Flarside, XLT, 351w E4OD
SD48b, Quarter Horse, Burn2

Re: Can we discuss MTEISF, MTEFTC, etc?

Unread post by wwhite »

I don't think there is such a thing as 'layman' terms with regards to Ford strategies.

Anyways, here is a snippet from the CDAN2 document:
8.13 FEATURE: TRANSIENT FUEL - V1.1_FTRAN_TRANSIENT_FUEL (CDAM0)

8.13.1 BACKGROUND TRANSIENT FUEL LOGIC (CDAM0)

OVERVIEW

Background:

A liquid fuel film resides on the walls of the intake manifold. The film
mass varies primarily with manifold absolute pressure and manifold wall
temperature. During steady state conditions, the film mass is constant. The
rates of condensation and evaporation on the manifold walls are equal.
During transients, the film mass changes creating air/fuel ratio errors.

. During accelerations, the film mass increases. Fuel will condense faster
on the manifold walls until equilibrium is reached. In an uncompensated
system at stoichiometry, fuel is diverted from the cylinders, resulting
in a momentary lean condition.

. During decelerations, the film mass decreases. Fuel will evaporate
faster from the manifold walls until equilibrium is reached. In an
uncompensated system at stoichiometry, fuel is added to the cylinders,
resulting in a momentary rich condition.

The problem is magnified in closed loop fuel systems because the fuel control
will incorrectly chase the transient air/fuel excursions.

Intent:

The Transient Fuel Compensation Strategy (TFC) augments the closed/open loop
fuel control to keep cylinder events at the desired air/fuel ratio during all
engine transients. The goals are:

. To eliminate lean air/fuel excursions during accelerations.

. To eliminate rich air/fuel excursions during decelerations.
DOHCTOR_32V
Posts: 79
Joined: 2021 Apr 24, 12:07
Location: USA
Vehicle Information: 95 Cobra

Re: Can we discuss MTEISF, MTEFTC, etc?

Unread post by DOHCTOR_32V »

I have read the CBAZA documentation, but it's not very detailed. I realize that my education is not the purpose of the document.

I found some internet gold to share on this subject. It was posted by Decipha and Mitchb. I hope others get a better understanding through this info.

If anyone can add to this, that would be great!


From Mitchb

"OK, we'll start with anticipation logic. You either have this 'on' or 'off'. This logic attempts to determine what the cylinder filling will be during the next two intake events. I turn this off. In some cases, this acts like a filter and delays fueling under some transient conditions. This should be enabled in most stock calibrations. If you turn this off, you will have to radically change several other transient calibrations to make this work. The revisions will end up being to decrease the amount of transient fueling you put into the motor. This is the single largest factor that will affect transient fueling, so start with this on or off. The calibration parameter for this is U32 ARCHSW - Switch to enable use of anticipated cylinder air charge, 1 -> use anticipated value,

The next largest factor is FN1321 - equilibrium intake surface fuel table. Plot this table in excel so you can have a curve to reference. This is a plot of load (MAP) vs ECT. Plot this for one ECT like 180 degrees. The curve represents the amount of fuel you are adding to the normal closed loop fueling to compensate for the fuel that ends up condensing (or evaporating) on the port walls during a load transition. Don't be afraid to make large changes here as you sometimes need to clearly see the trends when you change this curve.

Working with this table is FN1322AL and FN1322DL - transient fuel accel and decel time constants. This determines the frequency using the foreground and background loops that the above table will be referenced and the transient fuel compensation will be updated. This has a minor affect.

Along with FN1321 and equal in magnitude is FN313 (TA/TD-if you have these two calibrations) - transient fuel RPM multiplier. This is an XY pair of 6 and directly multiplies the results of FN1321.

The next largest factor is manifold volume - F32 air manifold volume - Intake manifold volume for use in manifold filling model, liters. This is units of liters. Making this smaller brings the transient fueling in faster. The secondary affect is the make the amount of fuel added larger with increasing manifold volume, although this is a minor affect.

You may have a manifold volume or filter used during decel - you'll have to look for this.

The next most significant calibrations are FN052M and FN052N MAP at zero aircharge and slope of MAP at zero aircharge. Plot these separately on one sheet using excel. They work together. The two have a large role in determining TFC. They also have a large factor in determining how much you fuel the motor and this is aside from your MAF curve. How far you have this from being correct for your motor will ultimately show up in your long term fuel trims. This will be corrections to errors in fueling.

Some other things to look at are TFC at idle and RPM above idle during dashpot to disable TFC.

It goes without saying that you have to have your injector slopes and MAF curve correct before you start tackling TFC. If you have scaled your displacement, your TFC will not work correctly without much rework. The best way to determine what you need to do in terms of transient fuel compensation is to look at your HEGO tracings - and you need to become proficient at this because your initial interpretation of what's happening is likely to be incorrect. Remember your closed loop fueling will try to correct for any transient fueling errors and you need to realize this when you look at HEGO feedback.

I threw this together fast without going into the methodology of how to actually use feedback data to change TFC, maybe that's for a later discussion. But, the load with failed MAF plays no role in TFC in any strategy before 2002.

Graphing all of the above gives you a clearer picture of what's happening and what you need to change to get a desired result. If you find you've gotten far away from where you need to go, then go back to an earlier calibration set and work from there. You'll find TFC tuning is a challenge and takes time, but you'll like the results once you understand what's going on.

What you must understand is the MAF is used as a feedforward input, the HEGOs as feedback, but the final fueling is determined by what the EEC calculates as a final cylinder aircharge. You'll know you've got a good calibration when your TFC is good and your short and long term trims have few corrections."






From Decipha

"...now to the tuning session

dyn_min_arc is the minimum airmass required to enable dynamic make up fuel, i set this to 0 in all calibrations

TFC_MIN, transient fuel must exceed this threshold to be added to the fuel calculation this scalar is bypassed for decel, i always set this to 0, the other idle transient switches will prevent transient fuel from causing idle surge

decel tip out fuel is multiplied by AIR_DEC_MUL, its a multiplier on manifold volume, typically ends up around 1.10 % or so

MTEFTC is the transient constant multiplier, it multiplies the constant tables the fn1322's

tfc_multa and tfc_multd are direct multiplier on transient fuel

all 3 of the fn313 functions multiply transient fuel, i always set these functions to all 1s

some of those weren't available until 98+, if your def doesn't have these available then don't worry its not a biggie you can still dial in transients pretty good without them

FN052N is the MAP AM slope, increase map slope where engine has became more efficient, however, at peak tq slope will be lowest, remember typically when you increase hp on the big end you loose tq on the bottom end

FN052M is the MAP RPM slope, MAP at max engine efficiency (0 vaccum and 0 boost), used for transient slopes, MAP at peak tq (RPM where engine is most efficient) will be significantly LESS than when the engine is out of its power band, the MAP slope is typically not effected below peak tq on a boosted engine, when boost is added the slope usually increases LINEARLY from just above the peak tq rpm to approx, 1.5x at 5250 rpm

fn1321 is the transient fuel table, its the same transient fuel table henry has been using since the 80s, its even in the gufb strat, increase/decrease the cells for lean/rich spikes on transients using AFR/lambse ratio (just like dialing in the maf) at least thats how i do it and it usually works out about right, if lean/rich spikes occur after the transient then increase/decrease the constant tables (the fn1322's)

fn1322al is the time in seconds that acceleration transient fuel remains active, typically you would reduce the cells that cause the hegos to over-enlean on transients due to transient fuel staying in too long, boosted engines typically want approx half the time for transient enrichment to remain active as they do when not in boost thats just what i typically find works out best

fn1322dl is the decel time constant that transient fuel remains active, typically on modified engines the lower loads during decel when at warm engine temp fuel needs to be removed for a longer period of time, 4 seconds isn't too uncommon at least in my experiences

fn1323a is the transient fuel global multiplier for TEISF (transient fuel) during acceleration, typically after 90 seconds most engines will want about half the transient fuel they want with the excess friction from startup, remember for every closed throttle low load decel condition, an accel condition is recognized when load comes back up as the rpm's near idle and the engine restabilizes, this is why it is important to dial in DASHPOT so transients aren't always compensating when they don't need to be

fn1323d is same as above except for decels, (closed throttle and tip out), IMO, this table is practically unneccessary, I always keep each column uniform regardless of time, typically additional friction from startup has very little effect on transient decel fuel requirements in my experiences


i was actually about to write up a transient fuel 101 thread a couple weeks ago but said the hell with it, in any case, im glad mitch agrees and im sure anyone whom spends any time dialing in transient fuel will too that a hego is the best way to dial in transients"
DOHCTOR_32V
Posts: 79
Joined: 2021 Apr 24, 12:07
Location: USA
Vehicle Information: 95 Cobra

Re: Can we discuss MTEISF, MTEFTC, etc?

Unread post by DOHCTOR_32V »

Decipha, why do you and Henry have MTEFTC set at zero on the T4M0 / T4M2 tunes? As you know, J4J1 has it at 1.
dleach1407
Posts: 468
Joined: 2021 Mar 21, 15:17
Location: Colorado Springs, CO
Vehicle Information: 95 Mustang GT, CBAZA Quarterhorse
331, 190 11R heads, Edelbrock Victor 50 manifold, F303, T5, 76mm Turbo, 91 octane, Returnless dual pump 03 cobra tank, Behind bars rails, 80# siemens injectors
wbo2_030MtxL

57 F100, RZASA, 04 Crown Vic ecu and harness, 302, GT40 heads, 4r70w, 80# deka5 shorties, Holley carb style throttle body, Speedmaster high rise intake manifold

Re: Can we discuss MTEISF, MTEFTC, etc?

Unread post by dleach1407 »

DOHCTOR_32V wrote: 2022 May 27, 14:50 Decipha, why do you and Henry have MTEFTC set at zero on the T4M0 / T4M2 tunes? As you know, J4J1 has it at 1.
The stock bin for J4J1 that i have is set to .500 for mteftc and .125 for t4m0. .
DOHCTOR_32V
Posts: 79
Joined: 2021 Apr 24, 12:07
Location: USA
Vehicle Information: 95 Cobra

Re: Can we discuss MTEISF, MTEFTC, etc?

Unread post by DOHCTOR_32V »

Hmmm, I looked at those in BE earlier and it shows a 0 or 1. TP does indeed show it as you said. Thanks
dleach1407
Posts: 468
Joined: 2021 Mar 21, 15:17
Location: Colorado Springs, CO
Vehicle Information: 95 Mustang GT, CBAZA Quarterhorse
331, 190 11R heads, Edelbrock Victor 50 manifold, F303, T5, 76mm Turbo, 91 octane, Returnless dual pump 03 cobra tank, Behind bars rails, 80# siemens injectors
wbo2_030MtxL

57 F100, RZASA, 04 Crown Vic ecu and harness, 302, GT40 heads, 4r70w, 80# deka5 shorties, Holley carb style throttle body, Speedmaster high rise intake manifold

Re: Can we discuss MTEISF, MTEFTC, etc?

Unread post by dleach1407 »

Btw, thanks to everyone postng info about the transient settings. It's helping me try to figure out what do do with my setup.
Post Reply