MkII Fuel Cut Defencer
From: "Kostas G.D.Chryssos Ph.D."
Date: Wed, 01 Oct 1997 21:36:11 +0300
Hi everybody,
I have just finished ( had it finished...) a new design for a FCD unit.
It has two adjustable settings, one to be set just prior to engine cut-off
trigger point and a second at a point where the driver would like to have
the FCD by-passed so that the safety feature in employed say over 16 PSI
etc. It is an electronic circuit with 4 wires, one to +12V switched, the
other to ground, and the other two one to the boost sensor and the other to
the input of the ECU, similar connection with any other FCD. There are also
2 trimmer pots for setting T1 and T2. I have found very convenient to
adjust the settings as follows:
Remove the rubber pipe from the boost sensor (car idle) and block it.
Connect another rubber pipe to the port of the sensor and a small hand held
air pump ( I used the one on the blood pressure meter).
Connect a mechanical pressure meter on the same pipe with a T junction.
Pump air slowly into the sensor and note the reading on the pressure meter
and the front panel boost meter just to have an idea to what pressures the
panel meter works/indicates.
In the meantime connect a digital voltmeter to the output wire of the
sensor. If you take a thin cloth pin or needle you can puncture the wires
insulation close to the sensor and connect the meter without damage to the
wires. You must expect a ) to +5Volts readings there in relation to the PSI
you pump in. Take notes every PSI or so.
At the same wire the 5V readings are measured the FCD input is also connected.
Read the output of the FCD, it should follow the input.
Add pressure till the cut-off point for the particular engine ( the FCD is
universal in this respect)
Back off the pressure by 0.5 PSI and adjust the T1 of the FCD so that the
output voltage does not change any more.
Increase pressure to the level you want the FCD to re-engage and adjust T2
for a voltage jump to a value equal to the input voltage.
The FCD is now programmed.
I will send a copy of the electronics upon passing of all tests for bugs
etc ( no it is not digital ) to the MR2.COM so that anybody can copy it. (
no royalties involved).
(68k JPEG) 
(116k JPEG)
Regards to all,
Kostas G.D.Chryssos Ph.D.
ELFON Ltd., 30 Ikarias str., GLYFADA 16675
Athens, HELLAS (GREECE)
Tel: ++ 30-1-9628212 Fax: ++ 30-1-9649833
e-mail: sv1bt@compulink.gr / sv1bt@otenet.gr
From: "Kostas G.D.Chryssos Ph.D."
Date: Mon, 10 Nov 1997 20:58:21 +0200
Subject: MR2 T Boost input to ECU / FCD set points
For those who will want to tune the FCD I have posted, they can consult
the values of the Turbo boost in PSI plot that I have prepared plotted
against the DC Voltage input to the ECU for a 91T model. This plot is
available to anyone interested by direct e-mail. I have also marked the
corresponding indications of the stock front panel meter.
A good point to adjust for set1 point is 0,8 Bar ( 11,60 PSI) which
corresponds to a voltage of 4,25 Volts.
A good point to adjust for set2 point is 1,1 Bar (15,95 PSI) which
corresponds to a voltage of 4,83 Volts.
(86k JPEG)
Interesting to note that the stock front panel meter will point at the 8th
division mark above 0 (the ref mark about 1/3rd from the bottom of the
scale) at a boost pressure of 0,40 Bar ( 5,87 PSI) will make it to the 10th
(last division on the marked scale of the meter ) at 0,5 Bar (7,25 PSI) and
will clear to the top above the + mark of the meter) at 0,6 Bar (8,7 PSI).
The sensor's maximum practical output ( just above 4,9 volts) is reached at
a boost pressure of 1,23 Bar ( a bit over 17,40 PSI) .
Regards,
Kostas G.D.Chryssos Ph.D.
ELFON Ltd., 30 Ikarias str., GLYFADA 16675
Athens, HELLAS (GREECE)
Tel: ++ 30-1-9628212 Fax: ++ 30-1-9649833
e-mail: sv1bt@compulink.gr / sv1bt@otenet.gr
(68k JPEG) 
(116k JPEG)
Regards to all,
Kostas G.D.Chryssos Ph.D.
ELFON Ltd., 30 Ikarias str., GLYFADA 16675
Athens, HELLAS (GREECE)
Tel: ++ 30-1-9628212 Fax: ++ 30-1-9649833
e-mail: sv1bt@compulink.gr / sv1bt@otenet.gr
(86k JPEG)
Interesting to note that the stock front panel meter will point at the 8th
division mark above 0 (the ref mark about 1/3rd from the bottom of the
scale) at a boost pressure of 0,40 Bar ( 5,87 PSI) will make it to the 10th
(last division on the marked scale of the meter ) at 0,5 Bar (7,25 PSI) and
will clear to the top above the + mark of the meter) at 0,6 Bar (8,7 PSI).
The sensor's maximum practical output ( just above 4,9 volts) is reached at
a boost pressure of 1,23 Bar ( a bit over 17,40 PSI) .
Regards,
Kostas G.D.Chryssos Ph.D.
ELFON Ltd., 30 Ikarias str., GLYFADA 16675
Athens, HELLAS (GREECE)
Tel: ++ 30-1-9628212 Fax: ++ 30-1-9649833
e-mail: sv1bt@compulink.gr / sv1bt@otenet.gr