research shows that the efficiency of fuel engine can be increased by modifying
the coding of the vehicle’s ECU to alter the air/fuel ratio and spark engine’s
ignition timing without a visible decrease in automobile performance.

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Background and Problem Statement

fuel economy for post-production automobiles can be improved noticeably with a
low cost. What attracts people the most is fuel efficiency in consumer
transportation which has great deal of attention. There are many possible ways
in which the fuel efficiency of engines can improved, which would support in
the reduction of dependence on import of oil, the mitigation of climate change,
and other economic and environmental benefits.  

a major attention is given on the automobiles that are yet to be marketed and
not to the vehicles that are already on road. Excluding the huge number of
possible alternative fuel systems which are currently being produced or
developed, there are various other mechanical and physical variables which have
an impact on the way the internal combustion engine, transmission and other
components of a typical car or truck interact. These component interactions
when coupled with the effects of the natural world on the vehicle in motion
have a great deal on the thermodynamics of the engine operation and noted fuel
efficiency. Hence, there are different ways by which the fuel efficiency of the
vehicle can be affected, with variance in the observed gains in fuel efficiency
depending on the method utilized.

such as cars and trucks which are already on the road will continue to have an
immense impact on fuel consumption in the U.S. While there are researches going
on upon the identification of novel technologies for the future personal
transportation, the majority of the world’s population depends on petroleum for
future personal transportation. There are various other alternatives developed
such as fuel vehicles other than petrol, hybrid cars and electric vehicles,
although their market share is and is continued to be projected low.

Furthermore, a wide segment of population cannot readily purchase new cars that
have improved technologies; therefore, such technologies will be economically
accepted only on the secondary market.

project was aimed to accomplish two goals. First, the examination aimed to
discover attainable fuel-efficiency gains from the reprogramming of vehicles
equipped with early ECUs. Second, to establish a platform which provides
further empirical research on fuel efficiency and the modification of
automobiles for such purposes may be conducted. With these two goals in mind,
both the experiment and the modification of the vehicle were designed.





Experimental Setup

idea is small scale and is planned as a simple proof-of-concept for the basic
protocol for increasing fuel efficiency in a post-production automobile through
the manipulation and alteration of programmed fuel injection. In this study,
with the smallest amount of possible modification, the efficiency of fuel
economy is intended to be achieved. This resulted for the study to accomplish
its two main goals: 1) To improve the fuel economy by low-cost method.                     2) To establish a base
upon which more complicated methods can be investigated, which in turn, may
produce larger gains.

Vehicle Characteristics

this study is intended to provide proof of the concept, an ideal vehicle was
chosen. The important characteristics required of the car were that it should
be commonly used ( popular vehicle) ,should also be easily available on the
resale market, it should have a low cost, it must have ECU turning system which
is commonly available and also, it should have a high fuel efficiency.

 For this study, a 1994 Honda Civic DX sedan
was purchased. A Honda CIVIC DX was chosen as this vehicle met all the required
characteristics of an ideal car. As mentioned by its widespread commercial
availability and frequent mention in trade for a, it is known that Hondata
system has one of the best ECU turning systems on the market. It was developed
for the 1992-11995 Honda Civic. The fifth generation of Honda Civic is said to
be the most successful cars ever produced and it’s ever present in both
modified car communities as well as low cost used car throughout the U.S. It
had a 1.5 liter, four-cylinder D15B7 engine which was recently redeveloped and
turned up. This could be regarded as a reliable basis for turning.

General Summary of the Hondata s300 Turning System.

the availability of the Hondata s300 turning system is easy, the decision to
use a Honda Civic as the experimental vehicle was made. This system consists of
microchip installed on the vehicle’s ECU. It is included within a logic
controller that guides the engine to obtain information from the s300 and it is
directly programmable as opposed to the controller installed within the OBD-1
P06 ECU. The s300 is widely known by many higher-end car shops and has been
fine turned amongst the aftermarket community. It consists of a USB socket and
allows connection with a laptop computer and manipulation of ECU programming
through Hondata software program. This program allows a real time monitoring of
engine performance, and also provides three-dimensional views of graphs of both
the fuel and ignition maps utilized by the ECU to control the fuel injectors
and spark plugs based on engine temperature, revolutions per minute, and oxygen
sensor readings, with an additional capacity to include other inputs. An
aftermarket turbocharger or a switch to an alternative fuel source can
incorporated by performing modifications using the s300.

Vehicle Operation

investigation of the effect of ECU modification was made through a test-driving
protocol which is roughly called as “normal” driving. Hence, a driver needs to
have an understanding of the day-to-day schedule and driving protocol should be
obeyed in this study. The driving conditions were mixed, meaning, 40% of miles
was driven within city limits and 60% of miles in highway conditions. The
different other variables that were approximately held constant are tire
pressure, the weight carried by the vehicle, along with oil and other fluid
levels. Also, the observed gas mileage and other engine performance
characteristics was noted based on driver observations.


trained technician named Erich Uhlman at Pre, performed turning. Pre is vastly
known for its excellence in the area for its turning and modification of cars
for personal use and also, track and racing applications. Auto turning and
repair shops usually use dynamometers to measure power output in the form of
output power which is measured in horsepower or kW and torque measured in N-M
or lb-ft throughout the rpm range of the vehicle tested. For this experiment,
dynamometer turning is utilized to provide reliable power output information
also allowing for finer turning of the air/fuel mixture by modifying the ignition
timing and fuel output with the help of an experienced technician. The use of
dynamometers also enabled for the testing of parameters at different engine
speeds safely, which enabled for more exact turning and solid basis for later


table below shows the Fuel Efficiency Results for Each Experimental Stage











Base Tune





Lean Tune





Lean + Spark






article outlines the results of the fuel efficiency protocol testing. The
overall fuel efficiency results are as shown in the above table. It is noted
that the largest increase occurs in the final stage of the experiment when the
fuel leaning was coordinated with the ignition spark timing, which allowed for
the higher levels of leaning than was possible when only reducing the fuel
output. It is noted that the overall average fuel efficiency increased by 6.07
mpg, and the maximum fuel efficiency experienced during highway driving
increased by 13.02 mpg. This suggests that the protocol for fuel leaning is
most effective in improving the top gear efficiency of used vehicle engines.