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DOES THE
ENGINE HEISTATE OR
STUMBLE?
RAISE LEFT 6 BOXES
OF THE
“Rate of Change of MAP
Sensor”
TABLE 10 UNITS*
YES
* Most of the time, fuel pulse
width needs to be added to these
tables if the engine doesn’t rev
smoothly. A lot of fuel needs to
be added before the engine
stumbles due to
too much
fuel.
As always, if the symptom gets
worse, try taking fuel out. Spark
advance can also have an effect.
ACCELERATE AT A
MEDIUM RATE
Note: This flowchart is slightly simplified. See
accompanying text for details.
GOOD! MAKE
ANOTHER RUN TO
DOUBLE-CHECK
TUNING. THEN
PROCEED TO HIGH
LOAD TRANSIENT
TUNING
YES
RAISE LEFT 6 BOXES
OF THE
“Pulse Width – Rate of
Change of TPS”
TABLE 0.3 mSec**
DOES THE
ENGINE HEISTATE OR
STUMBLE?
ACCELERATE AT A
MEDIUM RATE
NO
NO
** Avoid making too much
change to the TPS enrichment
table, as this will affect low load
transient response. Concentrate
the most on the MAP
enrichment table, as this has the
most affect on medium load
transient response.
Figure 21 EFI Tuning Guide—Medium Load Transient—After Base Map is Fully Tuned
GOOD! MAKE
ANOTHER RUN TO
DOUBLE-CHECK
TUNING.
DOES THE
ENGINE HESITATE OR
STUMBLE?
* Most of the time, fuel pulse
width needs to be added to these
tables if the engine doesn’t rev
smoothly. A lot of fuel needs to
be added before the engine
stumbles due to
too much
fuel.
As always, if the symptom gets
worse, try taking fuel out. Spark
advance can also have an effect.
YES
NO
FLOOR GAS QUICKLY
(DRAG RACE LAUNCH)
RAISE RIGHT 10
BOXES OF THE
“Rate of Change of MAP
Sensor”
TABLE 10 UNITS*
Note: This flowchart is slightly simplified. See
accompanying text for details.
Figure 22 EFI Tuning Guide—High Load Transient—After Base Map is Fully Tuned