and Multi Port Fuel Injection to a New Level.
to Tuning, Part 2
This paper is an introduction to the basics of EFI tuning. It
covers what changes to make and why. Although similar to the ODB1 GM systems there are some
The EBL Flash
system allows the user to easily make changes to the tune and try them
out. Please see the first part of the Introduction to Tuning to
become familiar with the use of a calibration editor and the use of the
EBL Flash What's Up Display (WUD).
For stock engines and drive train there are 30-some
calibrations provided with the EBL Flash. One of these will be a good
starting point for your vehicle. Most likely no other changes will be
required. Just flash it in and proceed with some VE Learns.
the other hand, if the injectors are larger, the fuel pressure has been
increased, heads or cam changed, then some of the calibration
parameters will require changing prior to starting the engine. In this
case select a base calibration that is close to the engine and
transmission and modify it. You can also copy and paste from other provided calibrations to create a new starting calibration.
Then once an engine has been modified with better heads, cam, and
exhaust, additional tuning will be required.
that if at all possible start your tuning with a stock engine. Then
move on to making changes to the engine. This will allow you to gain
experience in tuning before it becomes an absolute necessity.Which then
makes it easier to deal with tuning a modified engine.
To start out look through the EBL_F_BINs.txt file (on the CD which should be copied to your PC/laptop).
This lists the current calibrations for the EBL Flash. Select one that
closely matches your engine and transmission combination. Read the BIN
into your calibration editor and immediately save it with a different
filename. This will be your starter BIN (also known as a 'calibration').
that the EBL_Calibration.html file lists the tuning parameters. It is
helpful to refer to it while reading through this introduction. This
entries in the calibration document, the calibration editor, and this
paper will match. In this paper the entry names will be double quoted.
there are additional notes on setting up for VE Learns in the
What'sUp.html document. Please refer to those prior to setting up
a VE Learn. It isn't difficult, it is just that certain items
need to be under control for a good learn to take place.
The first thing to check is the "Number Cylinders(6=192 8=0)"
parameter. It must be correct for the spark timing to be correct. This
is a set-it and forget-it parameter unless the engine is swapped for
one with a different number of cylinders.
check/set the "SA - Initial SA" value. This value must match the actual
distributor base timing. The ECM needs to know the base distributor
timing so that it can properly program the distributor for the
commanded timing value. So if the distributor base is at 0* BTDC, set
this value to 0*. If the distributor base is at 4* or 6*, then set this
parameter to match at 4* or 6*.
A typical base timing setting is between 0* and 10* BTDC.
Note: the base distributor timing is set with a timing light on
a warm engine with the EST/BYPASS connector open.
base timing is used during cranking. It may be
to suit the engine. If the engine windmills on cold cranking then a
higher base & matching initial setting can be used. If the engine hard
cranks hot, then a lower base & matching initial setting can be used.
Typically, an engine with more cam overlap requires a greater base
& initial timing setting for a good start up.
Injector Flow Rate and
This will need to be changed for any change in engine displacement,
change in fuel pressure, or a change in injector flow rate.
The EBL P4 and EBL SFI-6 use separate engine displacement and injector flow constants:
- INJ - Injector Flow Rate**
- INJ - Displacement of 1 Cylinder**
EBL uses a value called the Base Pulse Constant (BPC) to define the
injector flow rate and engine displacement. It is the two of them
rolled together into a single value. There are two tables that need to
be filled in with the BPC value(s):
calculate the BPC value(s) there is the EBL_Utility Windows program.
Earlier releases of the EBL were supplied with spread sheets for the
- "BPC - BPC vs VAC"
- "BST - BPC vs Boost"
the EBL_Utility or spread sheet fill in the values for engine displacement, number of
cylinders, fuel pressure and so on. The BPC tables values are shown on
The BPC values, which are shown in red, can then be copy & pasted directly
into the calibration editor.
Note: it may be required to change the AE MAP & TPS PW tables. See the Acceleration Enrichment section for more information.
main and extended SA tables may or may not need to be changed. The main
influence on SA is the head material and the chamber design (shape
& size). Other considerations are the vehicle weight, chamber
temperature (air intake and manifold also affect this), induction
design, fuel octane, compression ratio, and gearing.
If the heads on the engine match the base calibration you started with,
then for now leave the SA tables alone.
if as an example you installed Vortec heads on your L05
Pick an L05 calibration that matches your vehicle along with the
transmission type. Then in your calibration editor copy over the main
& extended SA tables from the EBL_F_1000.bin calibration. The _1000.bin calibration has Vortec SA tables:
If running a non-swirl port iron head then the base LG4 calibration SA
tables should be used ('416 heads, EBL_F_TB.bin).
- "SA - Main Table"
- "SA - Extended table"
are also a couple of calibrations for aluminum headed engines. Although
both are for the Corvette '113 heads, one is for a TBI single plane
manifold and the other is for the TPI system..
Volumetric Efficiency (VE):
the engine is basically stock, or at the most a mild cam it is best to
leave these alone. The VE Learning of the WUD will take care of the VE
If you are setting up a fire breathing dragon of
an engine then these tables should be adjusted. In general a lower VE
at lower RPM ranges and higher VE in the upper RPM range. At the same
time experience in tuning these types of engines is required. You may
need to rough in the lower VE areas several times as you work on
getting the engine to run. Then move on to doing VE Learns.
Engine RPM Limiting:
are two functions provided in the EBL to limit the engine RPM. One
reduces the SA to cause a loss of power. The other turns off the
injectors (fuel cut) to shut off the engine.
purpose of the spark reduction feature is to keep the driver
over-revving the engine. It causes a loss of power that the driver can
and alerts them to the fact that they need to up shift. It should be
set slightly above the desired shift RPM.
purpose of the fuel cut RPM limiter is to protect the engine if there
is a sudden loss of traction or drive line breakage. So it should be
set high enough that it is not hit even with spirited driving.
about the high RPM fuel cut limiter: if using any type of auxiliary
fuel unit set these to a high value (10,000 RPM). This includes an alky
set up, aux injectors, and so on. The reason is that cutting the main
injectors off while still supplying fuel by another means
will lean out the engine, not shut it off. This in turn can cause
melted parts, which is bad.
limiter RPM values have separate entries in the calibration editor
dependent upon the engine cylinder count. There are also valet mode
parameters, so be sure to set the right ones.
- "OVSPD - RPM fuel Cutoff (8cyl)"
- "OVSPD - RPM fuel Resume (8cyl)"
- "OVSPD - RPM SA Reduction (8cyl)"
- "OVSPD - SA Reduction"
Vehicle MPH Limiting:
as the RPM limiter there is vehicle speed limiting. It too uses a SA
reduction and a fuel cut. They are set to 170/168 MPH in the supplied
calibrations. So if going for a land speed record set them to 255 MPH
to disable the MPH limiters.
- "OVSPD - MPH fuel Cutoff"
- "OVSPD - MPH fuel Resume"
- "OVSPD - MPH SA Reduction"
the engine is cammed then the idle speeds most likely need to be
increased. There are two tables for this: one for in park/neutral (auto
only) and another for in drive (stick & auto).
easiest method of increasing the idle speed is to highlight all entries
and add an offset. Use the same offset for each table. This retains the
higher idle speeds for a cold engine along with the higher idle speed
when in prk/neut.
- "IAC - Idle Speed: Drive"
- "IAC - Idle Speed: Park/Neut"
INJ - MPG Injector Flow Constant:
WUD uses this value for the trip display calculations. Set it close to
the required value. Then as the tune comes together do some actual
testing and make minor corrections. Even if this isn't done, it may
still be used as a relative value to gauge tuning for increased fuel
AirFlow - Displacement
Last but not least, the "AirFlow - Displacement Scalar" value. Note that this value is not critical.
I mention it here as later once tuning has been started the tuner finds
it and gets worried about it. So set it now and forget about it. Also
note that it tops out at about 487 CI. As mentioned, it is not
critical. So if running a 502CI engine, just set it for 487 and forget
If your tune if nearly complete and you find the airflow scalar way
off, just leave it.
Now That We
Have a Starter Calibration:
Working With the New
Now it is time to flash in the calibration and start the
engine. Be sure to save the BIN (ALT-F, S) prior to flashing it.
a data log in the WUD, then start the engine. You may need to use some
pedal to get it started or to keep it running. It all depends upon how
close the tune is. If it running OK then let it warm up and go into
closed loop. Can now observe the BLM value to see how far off the
At this point you need to decide whether to go
with the VE tables as is and let the VE Learning take care of
them. Or make some adjustments to the VE tables and flash in the
updated calibration. Same if the engine doesn't want to run. If it is
chugging and blowing black smoke, then it is too rich. If it surges in
RPM then dies, it is too lean.
Increasing the VE table
values will make the engine richer, and vice-versa a lower VE value
will lean the engine. If you are not sure of what area of the VE table
to change look at the log file in the WUD Analysis display.
Note: at this point
shut off the engine, wait 10 seconds, then restart it. This does an IAC
reset and sync's it with the ECM.
to make further tweaks to the VE table (Low Speed) until the engine
runs OK. You should be able to get it to idle and rev (go easy here,
keep the RPM reasonable) without issues. Can use the VE Learn feature
of the WUD during this time.
At this point there is something that needs to be mentioned. This is the mechanical set up of the engine.
Fuel pressure, fuel delivery, valve adjustment, distributor base
setting. These and other odds and ends will affect the tuning
process. The first sign that there is fuel delivery issues is that the
tune goes in circles. Other issues that crop up is excessive knocking,
no power, can't set the fuel pressure low enough. Wrong spark plugs,
incorrect firing order (wires on the wrong plugs), distributor
moving (hold down bolt not tight enough).
mention this is to keep in mind that the tune is only as good as the
mechanical set up of the engine. If the tune doesn't keep moving in a
forward direction, if the power seems low, ifyou feel as though you are
going in circles, then it can pay off to check other items.
first drive should be done in a low to no traffic area. A long driveway
is good. Otherwise go out at a time when the traffic is light. Take it
easy, make sure to start a VE Learn and to data log, then drive around
for about 10 minutes (with the engine warmed up).
upon how close the tune is the engine may or may not have run OK. There
is a good possibility that it stuttered, sputtered, surged, or chugged
at times. This is why the initial drives should be done in light to no
Take a look at the WUD VE Learn display
(corrections screen). Big corrections? Stop the VE Learn and flash in
the new calibration. Then set up another VE Learn, data log, and take
the vehicle for another drive.
Drive for another 10
minutes, stop and check the VE Learn corrections display. Same as
before, stop the VE Learn and flash in the new calibration. Each time
you do this the engine will be running better.
continue to do VE Learns go to a higher engine RPM. To do this hold the
gear longer before up shifting. Try to get as much coverage over the
load and RPM range as possible. You can also increase the length of
time driving before stopping the VE Learn and flashing in the new
Tips for good VE
- Hold the gas pedal steady, a learn can only take place in
steady state conditions
- Can use an up hill to hold an RPM with a higher load (MAP
- Get as much coverage as possible over varying roads
- Don't use the same route for each VE Learn
- NB based VE Learns will not learn at WOT (PE mode)
- WB based VE Learns can learn at WOT
the VE tables take shape the low RPM and low MAP area may need to be
manually changed. What can happen is that this area ends up higher in
value then the surrounding area. This is due to a VE Learn not able to
take place there. In this case just flatten out the lower RPM/MAP
triangle of the low speed VE table.
Can do this by dragging the graph of the VE table or using the fill
feature directly on the table. This is a before look at a VE table with a cam'd engine:
Then after the non-learn area has been flattened:
On the other hand the low RPM and high MAP area is used during cranking. So don't get carried away
and reduce the whole low RPM area.
the engine running better you can start looking into other items. This
includes but not limited to spark knock, idle speed, surging during
decel or idle, torque converter lockup or TH400 kick down,
acceleration enrichment (AE) and WOT power.
Much of the
required tuning will depend upon how the engine runs and the vehicle
drives. Along with how modified the engine is from stock. At this point
if the engine has bolt ons with a moderately increased injector flow
rate it will probably run rather decent.
If the engine is more heavily modified: heads, cam, intake, larger
injectors, then further tuning is likely to be required.
One aspect of the ECM software is known as a delta. You will read/hear
of delta TPS, delta RPM, or delta MAP. These are sometimes abbreviated
with a small 'd' and then the annunciator. Such as dTPS, dRPM, and so
on. So what is a delta value?
It is defined as the change
in value over time. The ECM software runs in time scheduled loops,
it is not free running. So it can keep a value in memory until the loop
runs again and know the time difference between the old value and the
new (current) value. If the old value is 98 and the new value is 110,
then the delta value is 12 (110 - 98). Deltas may be in the positive or
negative direction. Such as an opening throttle vs. a closing throttle
(dTPS). If the loop is run every 100 milli-seconds, then the old value
is a 100 milli-second delayed value. So the delta is over a 100
milli-second time period.
The other method of creating delta
values is by the use of a filter. By using a programmable filter value
(coefficient) the tuner can change how much delta there is. A filter
lags the change in a value based on both time and the value of the
filter. The acceleration enrichment (AE) parameters have a table of
filter values to create a dTPS and a dMAP value. By using a smaller
filter value the delta's are increased. For AE this increases both the
volume of AE fuel and the duration of AE fuel (more on this later).
The maximum spark advance an engine can use is defined by
either the detonation limit or the timing limit of the heads. Defined
by detonation is easy, the engine knocks and can either back off
the timing or run a higher octane fuel. The detonation will stop.
timing limit of heads is a little more difficult to discover. This
can be seen as the engine (many times) won't go into detonation. Keep
throwing more spark timing at it and it will not detonate.
does happen is that the power drops off and the engine gets rough. The
power drop off can be discovered on either a dyno or a track.
The roughness of the engine is something that the tuner needs to pay attention too.
that a rough engine feels fast, but it is slow. A smooth engine is
fast, but it doesn't feel fast. Use the data logs or a track to check
the vehicle rate of acceleration.
other aspects for tuning spark timing that should be considered. Spark
advance is a way of controlling the engine torque. More advance, more
torque. Less advance, less torque. This can be used to advantage.
a stick driven vehicle to much timing in the low RPM range can make the
throttle jumpy. Adjust accordingly for best driveability.
can use more WOT spark timing is the lower gears. As the transmission
is up shifted the air drag from the vehicle speed increases and the
engine acceleration slows. This requires less spark timing. For stick
vehicles the PE spark timing can be set according to which gear is in
There is launch mode (LM) spark advance specifically
for automatic equipped vehicles. Use the additional timing to quickly
bring the engine up against the torque converter. This provides better
performance and lower fuel consumption. This LM advance can also
be used for stick vehicles. It allows for more timing on take off
then would be used once a vehicle is up to speed.
During WOT operation heat is also building in the engine. Again, less
timing is required. Note that the EBL has a PE AFR enrichment over time
to aid in cooling the engine.
A quick mention of two additional spark reduction tables: the TCC locked retard table and the boost spark retard table.
the TCC locks it places an additional load on the engine. By using the
TCC locked retard the main SA table can retain enough SA for decent
performance with an un-locked TCC. Then once the TCC locks the tuner
can reduce the spark timing by the proper amount to reduce detonate or
roughness in the engine. A win-win with this one.
boost retard is used to reduce the spark timing as the RPM and boost
changes. Having this functionality in the EBL eliminates the need for
add on boost retard units.
At times deceleration can be troublesome. If too lean the engine
can start to surge. As the vehicle slows to a stop this surging can
carry into idle mode. Which can result in the engine stalling.
Best bet here is to manually increase the VE in the low MAP areas of the
RPM being used. This is usually in the idle to low RPM range of the
You can un-check the forced open loop during decel
option to do a VE Learn. However, since prop gains will then be active
and the AFR will get leaned out some. It is easy to get surging during
decel. This surging is why the decel is open loop in the provided
Another issue is that during decel the PW gets
small. Very little fuel is required. So it is easy for closed loop
INT/BLM to rise and fall while being unable to control the actual AFR.
This time it will start to buck as the fuel comes in and out.
the injector compensation offset will help in this regard. Which is
required for proper control of the injectors. But it doesn't always
correct the surging.
An aspect of decel is that the air/fuel
density in the chamber is very low. Which is difficult to light off. So
a little extra fuel goes a long way in preventing misfires. And it
isn't really a lot of fuel.
This extra fuel also helps when
the engine drops into idle. Otherwise idle can start to surge before
either settling down or stalling (it's usually one or the other).
The purpose of acceleration enrichment (AE) is to add fuel whenever the
throttle is opened or manifold pressure increases. The affect is to
prevent sags, lean backfires, and popping out of the throttle body.
In the carburetor world AE is known as pump shot.
The reason AE is required is that as the manifold pressure increases
fuel drops out of suspension and coats the walls of the intake manifold
and runners. The additional AE fuel makes-up for this loss to the
manifold/runners. Both TBI and MPFI systems require AE. With the TBI
system requiring higher levels, and MPFI being a little tricker to get
correct. The wet flow plenum on a TBI system buffers fueling
changes. This helps prevent rich & lean spikes by smoothing fuel
delivery to the chambers.
The higher the airflow velocity, the less fuel will be on the walls.
And, the less fuel will drop out of suspension with an opening throttle.
tuning AE there are a number of tables that can be used. There is both
delta MAP and delta TPS tables that control the volume and duration of
additional fuel. This added fuel is further changed by an RPM and CTS
Before AE is added there are a couple
of qualifiers. The TPS needs to have increased more then a set amount
for dTPS AE. And the MAP needs to have increased by a set amount for
dMAP AE. These are programmable parameters:
that the dMAP & dTPS AE functions are separate from each
other. IOW, it is possible to have MAP AE and not TPS AE.
- "AE - Delta Map Qualifier"
- "AE - Delta TPS% Threshold for AE"
Chain of events:
one or both of the thresholds have been exceeded the ECM will calculate
the AE fuel pulse width. The delta of the MAP/TPS will be used to look
up the PW value from the respective AE PW table:
The results of these two lookups are added together. Then compensated for by the engine RPM:
- "AE - MAP PW"
- "AE - TPS PW"
Then further compensated for by the engine coolant temperature:
of these compensations can increase or decrease the volume of AE fuel.
At higher engine RPM very little AE is required. The airflow through
the induction system is high enough to prevent the fuel from falling
out of suspension.
A cold engine requires additional AE fuel. So it is common to add to the CTS compensation as the engine CTS falls.
The final AE fuel is then added to the engine.
The MAP and TPS Filter Tables:
There is two tables of filter values based on the engine coolant temperature. One table for MAP AE and another table for TPS AE.
purpose of the filter tables is to create the delta MAP and delta TPS
values. The smaller the filter value the larger the delta. This is important to understand as it affects three areas of AE.
- "AE - MAP Filter"
- "AE - TPS Filter"
Remember that the smaller the filter value in the table the sooner, larger, and longer lasting the delta MAP/TPS value will be.
dMAP and dTPS values are used to check the threshold to see if AE is
required. And is used to lookup the AE PW from the PW tables ("AE - MAP
PW" & "AE - TPS PW").
A lower filter value also
increases the duration of the AE. It takes longer for the delta MAP/TPS
to return to zero once the current MAP/TPS stops changing.
the end the filter values affect three areas of the AE functionality:
the threshold for AE, the volume of AE, and the duration of the AE.
Affect on AE of Changing Injector Flow Rate:
the injector flow rate directly affects the volume of AE fuel. This is
because AE is pulse width based and is not affected by the BPC value.
best way to compensate for a change in injector flow is to use the
ratio of the old injector flow divided by the injector new flow rate.
Using that ratio compensate the two AE PW tables (MAP & TPS). As an
example, say that the 61 #/hr injectors are replaced with 80.5 #/hr
injectors at 18 psi. The new flow rate is then 94.7 #/hr.Creating the ratio:
61 / 94.7 = 0.64
into your calibration editor and open the two AE PW tables. Multiply
each entry by 0.64 (toolbox!). Save tables, save calibration
IAC Opening AE PW:
the AE parameters is an "AE - IAC Opening Fuel" term. For TBI systems
as the IAC opens (retracts, more steps), fuel needs to be added. That
is the purpose of the IAC Opening fuel parameter. It adds a small
amount of fuel each time it steps open some.
Note that MPFI engines typically do not require IAC opening fuel. And the PW is set to 0.
AE Variables in the Data Log:
What's Up Display Analysis screen Dump Log output of the data log
contains five columns of AE information. This data is helpful in
knowing what the delta values are along with how much AE is being added
to the engine. Here is a short snap shot of an AE event along with some
additional useful columns.
Some of the columns are:
sPW injector PW, sync
dTPS delta TPS%
tpsAE TPS PW in milli-seconds from the TPS PW table
dMAP delta MAP in KPa
mapAE MAP PW in milli-seconds from the MAP PW table
aePW final AE PW after CTS & RPM compensation
Note that the values don't always 'look' correct. This is because the
ECM is recalculating the AE 80 times a second. While we are data
logging at 17 times a second. However, they do give a decent picture of
how much and from where (TPS or MAP) the AE is being contributed.
RUNTIME RPM MPH MAP TPS sPW dTPS tpsAE dMAP mapAE aePW
00:00:44 1750 22 33 2 1.160 0.0 0.000 0.0 0.000 0.000
00:00:44 1700 22 34 3 1.709 0.8 0.137 0.0 0.000 0.458
00:00:44 1650 22 37 5 1.678 1.2 0.107 2.8 0.000 0.275
00:00:44 1650 22 38 5 1.770 0.4 0.107 4.4 0.000 0.458
00:00:44 1650 22 40 7 1.923 1.2 0.107 5.3 0.000 0.732
00:00:44 1675 22 43 7 2.350 0.8 0.107 6.6 0.076 1.083
00:00:44 1650 22 45 8 2.289 0.8 0.076 8.8 0.092 0.626
00:00:44 1700 22 47 9 2.808 1.6 0.122 8.4 0.092 0.732
00:00:44 1650 22 48 9 2.380 0.8 0.107 10.9 0.092 0.626
00:00:44 1625 22 51 10 2.899 0.8 0.107 11.3 0.107 1.190
00:00:44 1650 22 54 11 2.838 1.2 0.122 11.3 0.107 0.916
00:00:44 1675 22 57 14 3.204 2.0 0.153 15.0 0.137 1.419
00:00:44 1700 22 62 15 3.235 1.2 0.107 16.6 0.137 0.793
00:00:44 1675 21 64 15 3.082 0.4 0.076 18.4 0.122 0.458
00:00:44 1675 22 65 15 2.899 0.4 0.000 16.3 0.137 0.504
00:00:44 1675 22 65 15 2.838 0.4 0.000 13.4 0.122 0.397
00:00:44 1725 22 65 15 2.777 0.4 0.000 13.8 0.107 0.397
purpose of injector compensation is to make up for the time it takes
for an injector to open and then close. The proper values can be
difficult to obtain, so many times they are guessed at based on results. Which in many
cases works out OK.
general terms the higher the fuel pressure the longer it takes for an
injector to open. Increased fuel pressures are more prevalent on TBI
systems. And as such should have the injector compensation values
increased. Check the 5.4l calibration with the 80# injectors at 22 psi.
Compare those values with some stock calibrations. That will give an
idea of what values can be used.
With port injectors there
is some information available for various injectors. If available then
it is worth using to update the calibration.
Decel Fuel Cut Off:
Not much to say about decel fuel cut off (DFCO). It is intended
as catalytic converter protection during long decelerations from speed.
The ECM does this by shutting the injectors off which cuts off the
supply of fuel to the engine. Once below a programmable MPH or RPM, or
the driver puts their foot back on the gas pedal DFCO is exited and the
injectors are re-enabled.
Just don't set the RPM or MPH limit too low as this will cause engine stalling (not fun).
stick vehicles with modified engines DFCO can be rather harsh. In these
cases you may need to disable it by setting the enable DFCO enable
temperature threshold high ("DFCO - Enable Temperature").
Torque Converter Lockup:
The torque converter clutch (TCC) is a mechanism that mechanically
locks the engine to the transmission. It is contained within the torque
converter. Only used with automatic transmissions, and is
not a requirement. Some automatic transmissions do not use a TCC.
The primary purpose of the TCC is to increase fuel mileage and reduce
transmission temperatures. A secondary benefit is that the torque
converter stall speed may be raised without excess slippage while
cruising with the TCC locked.
using a 4-speed auto (200-4R, 700R4) the first item to check is
whether the high gear switch setting is correct. Easy to do, take a
short drive with the transmission gear selection in D (not OD) and data
log. Then observe the data log on play back and check that the gear
indicator is D. If it shows OD, then change the high gear switch
selection in the calibration:
"Option Word 2 - Bit 5 - HiGrH", if checked, then un-check, and vice-versa.
will ensure that the proper low gear or high gear tables will be used
at the proper time. GM used both types of high gear switches and this
is the easiest method to find out which one is in the transmission.
The following is a brief description of the TCC calibration parameters.
Relock delays: these are delays that take place after the TCC unlocks before it is allowed to re-lock.
Forced lock MPH: once over this speed the TCC will be locked. No amount of TPS% will unlock it.
unlock: these are used to unlock the TCC while coasting with the foot
off or nearly off the gas pedal. The min/max is used to prevent TCC
lock/unlock chatter from having a single point threshold. Be sure to
have some amount of difference between the values. There are a pair of
min/max coast release values each for drive and overdrive.
thresholds to allow lockup: the vehicle speed needs to be above these
thresholds to allow the TCC to lock. Again, min/max values to prevent
lock/unlock chatter. There are a pair of min/max MPH threshold values
each for drive and overdrive.
Lock/Unlock vs TPS% and MPH:
these are the key tables to controlling the TCC. Two tables each for a
pair, then a pair each for in drive and in overdrive. These tables
define how much throttle is required to unlock and to re-lock the TCC
at various vehicle speeds (MPH).
The table "
TCC - LoGr TPS% to Unlock" is used to define when the TCC is unlocked.
Once the throttle position vs MPH is above the threshold the ECM
will unlock the TCC.
TCC - LoGr TPS% to Stay Unlocked" is used to define when the TCC is
free to lock back up. When unlocked, the TCC will re-lock once the
throttle position falls below the table threshold.
an example, say you are driving along at a steady 55 MPH with the TCC
locked. As the throttle is depressed to accelerate both the TPS% and
MPH increase. Once the TPS% is greater then the value in the "TPS% to
Unlock" table, the ECM will unlock the TCC.
Then once you
reach 65 MPH (the desired speed), you back off the throttle to go to a
steady cruise. Once the TPS% is below the value in the "TPS% to Stay
Unlocked" table, the ECM will relock the TCC.
TH400 Kick down:
The EBL will control the electric kick down of a TH400 transmission. Note
that the kick down solenoid in the transmission needs to be activated by
a relay. The relay is activated by the EBL ECM.
Several of the
included calibrations are set up for a TH400 kick down. It uses the TCC
tables for this purpose. If you want to set up a calibration
specifically then copy all of the TCC related parameters from a supplied TH400
calibration. Then set up the following option flags as shown:
The kick down and re-up-shift is controlled by the min/max
TPS% coast unlock parameters. Set both the low gear and high gear
parameters the same. While setting the minimum value slightly lower
then the maximum value.
- "Option Word 2 - Bit 7 - TCC " option to be checked (set)
- "Option Word 2 - Bit 2 - DcTCC" option to be un-checked (clear)
Word 3 - Bit 3 - TccHi" option
to be un-checked (clear), This will enable the kick down relay when the
output goes low.
- "TCC - LoGr Max TPS% Coast Unlock"
- 'TCC - LoGr Min TPS% Coast Unlock"
- "TCC - HiGr Max TPS% Coast Unlock"
- "TCC - HiGr Min TPS% Coast Unlock"
information on this page is intended to get a tuner started on
changes are required. Getting started and getting the tune worked out can be tricky. However, in the
end it all comes down to one question: how does it run? That is
the single most important question for the entire tune. When the
engine runs well, is tractable and driveable, delivers decent fuel
mileage and power, then the tune is good.
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EFI, All Rights Reserved.
of this document may
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