Land Rover Fuel Injection System Manual

							
LAND ROVER 
 
 
 
 
 
LAND ROVER 
FUEL INJECTION SYSTEM
 
DESIGN AND FABRICATION  
AUTHOR: CIARAN J BRADY
(cbrady at conehead dot org)
 
PROJECT DURATION: Feb to May 2010
 
Document version – 2.06 – 28th Aug 2010
 
 
 
 
 
 
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Main Index
 
Main Index
Figure index
Introduction
Overview
Selected Donor Vehicle
Donor vehicle parts supplied
Missing parts
Project duration
Refurbishment process
Fabrication / Design process
Fitting the injection Intake manifold
Selection of orientation of plenum and trumpets
Throttle linkage
Mass air flow sensor and air filter
Positive crank case ventilation (PCV)
The fuel system
The fuel tank
Vacuum plumbing design
Engine cooling
Idle control system
Exhaust and Lambda sensors
Bench testing the electrical wiring loom for the ECU
Loom analysis results
Road speed transducer system
Mounting ECU and main + fuel relays
Fitting the wiring loom
Fitting the 14CUX diagnostic reader
Using the diagnostic reader
Fuel cut off – inertia switch
Appendix A – 14CUX Fault Codes
Appendix B – Final notes, comments and links 
 
Figure index
 
Figure 1 – 1992 3.9EFi donor vehicle parts as shipped
Figure 2 – Plenum side view
Figure 3 – Plenum rear quarter view – fuel flow and return
Figure 4 – View of stripped intake manifold
Figure 5 – View of Intake runners
Figure 6 – Underside of plenum.
Figure 7 – Close up of plenum chamber pre-heater
Figure 8 – Close up showing the throttle linkage
Figure 9 – Drilled throttle assembly rivets
Figure 10 – Painted plenum - minus all ancillary components
Figure 11 – Sprayed idle bypass air valve housing and plenum pre-heat\
er
Figure 12 – Sprayed plenum complete with rebuilt throttle linkages
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Figure 13 – Rover V8 cleared down to the valley
Figure 14 – Left and right views of the V8
Figure 15 – Underside of original carburettor manifold (showing the \
plumbing)
Figure 16 – Underside of injection manifold
Figure 17 – Cooling plumbing for the heater matrix
Figure 18 – Intake front and rear view
Figure 19 – Injector testing results
Figure 20 – Finalised injection intake base
Figure 21 – Underside of plenum intake trumpet housing (note vacuum \
ports)
Figure 22 – Final position of the plenum
Figure 23 – Throttle fabrication
Figure 24 – Throttle cable mount bracket
Figure 25 – Mass air flow sensor schematic
Figure 26 – MAFS air path
Figure 27 – MAFS mounting bracket
Figure 28 – Mounted air filter (outer canister removed) clipped to \
MAFS
Figure 29 – PCV schematic
Figure 30 – Rover PCV coupling T piece
Figure 31 – View of the PCV system pipe routing
Figure 32 – Fuel system schematic
Figure 33 – Fuel pump and plumbing schematic
Figure 34 – Fuel pressure tap off point
Figure 35 – Idle control system
Figure 36 – Idle air supply pipe (red) – no longer used
Figure 37 – Idle air supply pipe (red) – finalised
Figure 38 – Welding lambda sensor threads into the exhaust downpipes
Figure 39 – Original loom connector layout in donor vehicle
Figure 40 – New loom layout suited to the target engine bay
Figure 41 – ECU Connector layout and numbering (and tune R)
Figure 42 – Injector electrical connectors
Figure 43 – Exhaust Lambda electrical connectors
Figure 44 – Fuel temperature sender electrical connector
Figure 45 – Coolant temperature sender electrical connector
Figure 46 – Throttle position sensor (potentiometer) electrical con\
nector
Figure 47 – Diagnostics plug (item 34 in workshop manual) electrica\
l connector
Figure 48 – Mass air flow sensor electrical connector
Figure 49 – Bypass air valve electrical connector
Figure 50 – Main cable connector linking loom to vehicle
Figure 51 – Main interface wiring chock block electrical connector
Figure 52 – Original loom fuse arrangement
Figure 53 – New loom fuse arrangement
Figure 54 – Condenser fan and heater/air conn electrical connectors
Figure 55 – Break out cable (close to ECU) wiring of 25 way female \
D
Figure 56 – Original coil wiring (when mounted on firewall)
Figure 57 – New coil wiring (when mounted on passenger side fender)\
Figure 58 – Original ignition switch wiring
Figure 59 – New ignition switch wiring
Figure 60 – Road speed transducer speedometer cable layout
Figure 61 – Wiring the diagnostic display into the loom plug
 
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Introduction
The land rover came with a standard induction system consisting of twin \
1.75” SU carburettors 
fitted to a 3.5 litre 9.35:1 compression ratio rover V8 using electronic\
 ignition. The vehicle 
employed a stainless steel exhaust system coupled with log style exhaust\
 manifolds. However, 
even after rolling road jetting of the carburettors and with good and ti\
ght linkages for both throttle 
and choke, they were the usual SU horror to drive with. The mixture was \
generally fairly good on 
cruise and part throttle – but cold starting was erratic to say the l\
east, and carburettor icing 
occurred regularly unless the weather was warm. It was quite typical to \
experience boggy 
stumbling running when having the audacity to approach traffic lights if\
 the engine was anything 
other than fully warm and even when fully warm, the engine idle speed wa\
s impossible to set with 
any degree of precision. 
 
Many will disagree, and some off roaders have very good reason to prefer\
 carburetion over fuel 
injection – but speaking personally, while I admire the elegance of t\
he constant vacuum 
carburettor, I have had first hand experience of both Stromberg and SU c\
arburettors on three 
vehicles in my life, and have equally loathed them all. 
 
This paper describes the conversion of the existing carburetion system t\
o a fuel injection system in 
full and is designed as a maintenance aid.
 
The conversion project started in February 2010 with an extended period \
of research. By the end 
of May the basic injection system was running. Fine tuning was then unde\
rtaken over a period of 
months. 
 
As stated, the primary intention when drafting this document was to have\
 a maintenance aid. 
However, anyone thinking about attempting the same carburettor to EFi co\
nversion on a Rover 
engine may find these notes useful even if just for background research \
– and so I took the 
decision to make these notes available on the web. If this is your aim -\
 have fun with the 
conversion. I can say that once it works, it is a vast improvement on ev\
en an ideally setup 
carburetion system.
 
Overview
When it comes to injection systems there are a number of systems capable\
 of fueling a Rover 
216CID small block engine.
 
A company in the US called FAST have created a system known as EZ-EFi wh\
ich is a self learning 
fuel injection system consisting of a large four barrel plenum fitted to\
 a custom manifold. The kit 
comes with an ECU capable of learning the fuel requirements of broadly a\
ny size engine – but the 
system is costly and very much aimed at larger displacement engines (th\
e CFM capability of the 
four barrel body is well over 1000CFM). By the time all aspects of syst\
em design were considered, 
the cost became prohibitive as did the injection air flow rates – sug\
gesting poor low speed 
performance for what would be a low revving four wheel drive vehicle. 
 
Another off the shelf DIY system is known as megasquirt. This consists o\
f an ECU designed along 
the lines of open-source with enough instructions / help to build a full\
y working injection system 
using additional off the shelf sensors, injectors etc. Megasquirt has a \
significant data logging 
capability which when coupled with a laptop provides a tremendous degree\
 of flexibility. It is also 
very popular and clearly is a viable option for this engine. However, it\
 works by referring inputs to 
a fixed map of fuel requirements. That means that any change to the engi\
ne necessitates the 
rebuilding of fuel maps in order to achieve proper fueling – an aspec\
t that appears only to be a 
useful asset when selling the product. To the end user it is a potential\
 liability. 
 
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There are advantages and disadvantages to these systems – but it is w\
orth factoring into the 
decision land rover research leading to a flexible, self adaptive system\
 known as the C family and 
which culminated in the 14CUX. This system has two major advantages. Fir\
stly it is self adaptive 
because it measures air flow into the engine using a mass air flow senso\
r – using that to determine 
the required amount of fuel. The air flow sensor employs a hot wire anem\
ometer to sense air 
intake – and is consequently known as a hot wire system. Within certa\
in limits, engine changes 
including displacement changes from 3.9 to 3.5 litre do not significantl\
y alter the 14CUX’s ability to 
correctly fuel the engine. Even aggressive profile cams are well within \
the range available to a 
14CUX – except when the overlap becomes greater than about 12 degrees\
. The second advantage 
is that it is a readily available given it was used extensively from 199\
0 to 1995 on range rovers – 
many of which are now being retired and broken.  
 
Bosch began the line of development for this system with the 4CU flapper\
 system in 1990 – so 
called because air flow into the engine was monitored by a moving flap i\
n the air flow. From 1985 
to 1989 the 13CU hot wire system was built which used a hot wire system,\
 cooled by incoming air, 
to detect the precise air flow into the engine. From then on, the hot wi\
re system was the primary 
line of development leading, in 1990 to 1995, to the 14CU system which c\
ulminated in the 14CUX 
system. The 14CUX included a small degree of diagnostics and was capable\
 of fueling the stricter 
emission controlled engine requirements of a vehicle running catalytic c\
onvertors running in 
different geographical markets. 
 
Injection systems following on from the 14CUX (including the GEMS land \
rover system) 
incorporated fuel injection and per cylinder ignition and so are far mor\
e difficult to transfer 
between vehicles. 
 
The 14CUX system was the one selected for the job of injecting the targe\
t engine. 
 
It is important to understand one key feature of the 14CUX system – n\
amely that there is no 
programming capability and little or no data logging built into the syst\
em. Effectively the 14CUX is 
a closed box. In reality, it is a straightforward microprocessor based s\
ystem using an EPROM 
(27128) to hold the program code along with a number of fixed fuel map\
s for open loop operation. 
The system is also capable of using lambda sensors in closed loop mode a\
t low speed. 
 
Selected Donor Vehicle
Type: Range Rover 3.9EFi
Registration: KXXX XXX (VIN confirms the year of manufacture is 1993)
VIN: SALLHAMM3KAXXXXXX
VIN decoded:
l     S=Europe region
l     A=UK origin
l     L=Land rover manufacturer
l     LH=Range rover model type
l     A=Wheelbase which includes
m     Series III 88”
m     Defender 90” extra heavy duty
m     Range rover classic 100”
m     Range rover (38A) 108”
m     Freelander
l     M=Body style which includes
m     Defender 5 door station wagon
m     Range rover classic 5 door
m     Range rover (38A) 5 door
m     Discovery 5 door
l     M=Engine 3.9 & 4.0L V8 EFi petrol
l     3=Gearbox – Chrysler 747 3 speed auto RHD
l     K=Year of manufacture 1993
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l     A=Built at: Solihull, UK
l     XXXXXX is serial number off the line
 
Donor vehicle parts supplied
The donor vehicle supplied the following parts. 
  1.  Full wiring loom including main and fuel relays and a socket for the\
 air conditioning control  relay
2.  ECU – stamped 14CUX
3.  Intake manifold
4.  Air horns 
5.  Plenum
6.  Throttle blade and linkage control
7.  Throttle potentiometer
8.  Air bypass valve stepper motor
9.  Under plenum heater
10.  Pipe work linking to mass air flow sensor
11.  Mass air flow sensor
12.  Air filter housing
13.  Air fliter
14.  All 8 injectors
15.  Fuel rail
16.  Fuel rail regulator
Missing parts
Key parts not included (could not be sourced from the donor vehicle) 1.  Inertia cut off switch
2.  Road speed transducer and twin speedometer cables one leading from g\
earbox and one  leading to the speedometer. 
3.  Oxygen (lambda) sensors
Project duration
The procurement of parts and research for the project began in February \
2010, with the start of 
the hardware phase commencing on the 12
th April 2010 (the day the major bulk of the 
components arrived). The project technically ended on 30
th May 2010 with the resolution of the 
last bug and the successful firing of the engine – a total of 49 days\
, but fine tuning and design 
improvements were then carried out on the system over the following six \
months in order to 
improve the reliability and operational stability of the design. 
 
The project was split into two parts – refurbishment and fabrication/\
design
 
 
Refurbishment process
Refurbishment involved stripping the received donor parts into individua\
l components while 
analysing the condition and operation of each to understand function. Th\
ere were a number of 
missing components – for example all the fuel system components up to\
 and from the injection rail 
were missing, as were all the vacuum plumbing components. The throttle c\
able and all the water 
plumbing parts were missing – and what made matters slightly more int\
eresting was that the 
water plumbing was quite different for the new intake manifold compared \
to the old. 
 
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Figure 1 – 1992 3.9EFi donor vehicle parts as shipped
 
The general condition of the donor parts was good and it was clear that \
the seller had done a good 
job of carefully removing the components in order to minimise damage. 
 
Figure 2 – Plenum side view
 
The idle control system was intact, as was the throttle linkages and the\
 fuel regulator (at the back 
of the fuel rail). The throttle linkages did however appear to be in a \
bad state of repair. 
 
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Figure 3 – Plenum rear quarter view – fuel flow and return
 
In the above photograph, you can see the flow and return feed pipes to t\
he fuel rail, connected to 
the even bank of injectors (with the injector for cylinder 7 visible at\
 the back left). Note the fuel rail 
connections – using a standard hose jubilee pipe on the low pressure \
side of the fuel regulator, but 
a machined fitment on the input high pressure side. This machined connec\
tion was tackled by 
removing the olive and the free rotating nut and using a standard jubile\
e clip connection on the rail 
after soldering a lip onto the pipe. 
 
 
 
 
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Figure 4 – View of stripped intake manifold
 
The above photograph details the front of the intake manifold when both \
the upper plenum and the 
inner runner manifold have been removed (shown just in shot on the left\
). Looking at the intake 
reveals all 8 injectors (the even set of four on the left of the photo,\
 the odd set on the right) 
connected between the fuel rail and the intake manifold. Note the four b\
olts (one was missing) 
fastening the intake to the manifold. You can see the fuel temperature s\
ensor screwed into the 
front of the fuel rail – and observe that this is not exposed to fuel\
. The sensor housing is actually 
brazed to a closed fuel pipe. On the thermostat housing another sensor e\
xists (to drive radiator 
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fans – but which was not employed in my design) and just underneath \
that is a coolant temp 
sensor used to drive the dash board gauge. On the front right hand of th\
e manifold you can see the 
coolant temperature sensor used by the fuel injection system screwed int\
o the manifold. Just 
above that is a water coolant pipe that feeds hot engine water to the un\
der plenum preheating 
plate. 
 
At the back of the manifold fuel rail you can see the fuel inlet right a\
t the back coming into the fuel 
rail, which sweeps round to all 8 injectors exiting into the fuel regula\
tor – with its vacuum hose 
connected (this hose routes to the vacuum port directly under the idle \
by pass air valve stepper 
motor. 
 
 
Figure 5 – View of Intake runners
 
The above photo shows the intake runners which bolt to the intake manifo\
ld via 6 bolts, and which 
the upper plenum (shown below) screws to via 6 hex head screws. An imp\
ortant point to note here 
is that the intake runner platform is actually reversible – and can b\
e mounted either way on the 
intake manifold – a design advantage that was used to simplify the va\
cuum pipe routing. 
 
Figure 6 – Underside of plenum.
 
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