Land Rover Fuel Injection System Manual

							
LAND ROVER 
Figure 44 – Fuel temperature sender electrical connector
 
 
Figure 45 – Coolant temperature sender electrical connector
 
 
Figure 46 – Throttle position sensor (potentiometer) electrical con\
nector
 
Note it was found to be difficult to electrically connect to the ECU(20\
) wire on the back of the 
throttle plug – therefore a short external wire has been added to the\
 loom extending the red ECU 
(20) wire to an exposed (but insulated) spade connector just behind \
the throttle plug. Testing the 
throttle voltage is then a matter of measuring the voltage between the s\
pade terminal and ground. 
The test results (after replacing the throttle potentiometer) were 0.4\
5v with the throttle closed, 
and 4.8v when open – ie: within spec. Note that a code 17 fault will \
be reported if this test is 
carried out – requiring an ECU power down to clear. 
 
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Figure 47 – Diagnostics plug (item 34 in workshop manual) electrica\
l connector
 
The diagnostic display (located inside the cab) is coupled to this plu\
g. 
 
Figure 48 – Mass air flow sensor electrical connector
 
 
 
 
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LAND ROVER 
Figure 49 – Bypass air valve electrical connector
 
 
 
 
 
 
 
 
 
 
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Figure 50 – Main cable connector linking loom to vehicle
 
The main cable connector was the primary method used to connect the inje\
ction loom to the 
vehicle electrical system. This plug was cut, and the wires fitted to a \
standard screw terminal chock 
block as shown below. 
 
 
Figure 51 – Main interface wiring chock block electrical connector
 
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LAND ROVER 
 
 
 
 
 
Figure 52 – Original loom fuse arrangement
 
 
The original donor vehicle injection loom fuses were heavily oxidised an\
d were replaced using new 
water proof connectors. Both old and new employed spade style fuses. All\
 connections were 
soldered. 
 
 
 
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Figure 53 – New loom fuse arrangement
 
 
 
 
 
 
 
Figure 54 – Condenser fan and heater/air conn electrical connectors
 
The original wiring loom included a relay and connector to drive and int\
erface to the air 
conditioning system. The primary motive for linking the two systems is t\
o enable an increase in 
engine speed when the extra running load of the air conditioning compres\
sor is enabled. As the 
target vehicle does not employ air conditioning – this circuit is ent\
irely unused. Nevertheless the 
connections are shown above.
 
 
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LAND ROVER 
 
Figure 55 – Break out cable (close to ECU) wiring of 25 way female \
D
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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Figure 56 – Original coil wiring (when mounted on firewall)
 
 
 
 
 
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LAND ROVER 
Figure 57 – New coil wiring (when mounted on passenger side fender)\
 
 
Figure 58 – Original ignition switch wiring
 
 
Figure 59 – New ignition switch wiring
 
 
Loom analysis results
The bench testing revealed only a small number of problems. The lambda s\
ensor wiring was open 
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LAND ROVER 
circuit (both sides). Also the two active feed wires (not the common \
feeds) to the injectors had 
been deliberately cut close to the ECU. It was assumed that the injector\
 wiring had been spliced in 
the donor vehicle with an immobiliser. 
 
The lambda fault was traced to a splice that had been made in the origin\
al loom again close to the 
cut injector wiring. All four faults were repaired with fresh wiring, an\
d heat shrink. At the same 
spot, there were a total of six additional wires which had at some time \
in the past been cut and 
extended. However, some of the wire joints pulled apart because the sold\
ering was poor quality, 
and some of the insulation was frayed and damaged. All of this wiring wa\
s rejoined using fresh 
soldered wiring and heat shrink insulation. 
 
After testing had confirmed end to end continuity, the loom plastic oute\
r sheath was removed in 
order to permit the movement of sensor positions to cope with the new pl\
enum orientation. The 
main parts of the loom remained intact, but the following items were mov\
ed. 
 1.  Throttle position connector was moved from odd to the even bank wiri\
ng
2.  Coil wiring (with the built in 6k8 R in the loom) was extended
3.  Mass air flow connector wiring was extended to the front of the engi\
ne
 
After which the loom was re-taped using self amalgamated tape and small \
link sections of sticky 
PYV insulation tape. At the end of that process, continuity was again te\
sted end to end. 
 
Road speed transducer system
The 14CUX uses a road speed transducer module to determine if the vehicl\
e is moving – and if so 
at what speed. There are two reasons why this module appears to be requi\
red. The first is so that 
the system can determine if the vehicle is stationary (at which point t\
he lowest idle speed is used). 
The second is to allow the injection system to limit the top speed of th\
e vehicle. 
 
The 1992 application used a simple chopper disc transducer in a metal mo\
dule connected into the 
speedometer cabling running from the gearbox to the vehicle dash speedom\
eter gauge. The unit 
has two wires, which are open circuit, but for every one revolution of t\
he speedometer cable, the 
wires go low resistance 8 times (400ohms). When correctly calibrated t\
he speedometer cable 
should rotate approximately 6 times for every single rotation of the roa\
d wheel.
 
The transducer itself is readily available – and there are a number o\
f third party companies capable 
of manufacturing speedometer cables to particular customer requirements.\
 As part of the 
fabrication, the road speed transducer was posted to Speedy Cables Ltd a\
long with the existing 
single speedometer cable and an explanation of the pair of new cables re\
quired. Within 2 weeks 
the parts arrived. 
 
Figure 60 – Road speed transducer speedometer cable layout
Fitting was straightforward with the road speed transducer cable tied to\
 the wiring loom running 
about 10 inches up the firewall on the drivers side. 
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