1995 E36 328 Coupe LPG Conversion - DRAFT

Disclaimer No warranty of any kind implied or given and no liability accepted for any loss, damage or injury, no

matter how incurred from reading or attempting to follow this document. This is merely how I

installed LPG on a car and I am not recommending this process.

Revision history This document is in draft and unchecked.

Safety first Work should only be undertaken by competent persons

If in doubt seek expert advice or help prior to starting the job and do not attempt it.

Do not place yourself or others at risk

A method of safely raising and supporting the vehicle is required and is not covered in this

document

The suspension system will be partially dismantled and additional care must be taken to

avoid inhaling or coming into contact with brake dust

Do a risk assessment before starting work. If in doubt do not attempt it.

It may not be advisable to work alone under a vehicle.

Before working on the electrical system the battery should be safely disconnected by

removing the earth lead.

Contents Disclaimer ............................................................................................................................................. 1

Revision history..................................................................................................................................... 1

Safety first ............................................................................................................................................. 1

Contents ............................................................................................................................................... 2

Background ........................................................................................................................................... 4

Cost Benefit Analysis ............................................................................................................................. 4

Tools ..................................................................................................................................................... 5

Parts list ................................................................................................................................................ 5

Design decisions.................................................................................................................................... 6

Design decision 1 – Tank ................................................................................................................... 6

Design decision 2 – Filler type and location ...................................................................................... 6

Procedure ............................................................................................................................................. 7

Mount tank ....................................................................................................................................... 7

Multivalve installation into the tank ............................................................................................... 14

Mount filler ..................................................................................................................................... 15

Rear to front LPG line ...................................................................................................................... 21

Solenoid valve and reducer mounting ............................................................................................ 28

Injector mounting ........................................................................................................................... 30

MAP sensor mounting .................................................................................................................... 33

ECU mounting ................................................................................................................................. 34

Wiring ............................................................................................................................................. 37

Overview ..................................................................................................................................... 37

Permanent live ............................................................................................................................ 39

Permanent earth ......................................................................................................................... 39

Ignition live ................................................................................................................................. 40

RPM feed .................................................................................................................................... 40

LPG injector connectors .............................................................................................................. 41

Petrol injector connectors .......................................................................................................... 41

Lambda sensor wires .................................................................................................................. 43

Reducer temperature sensor ...................................................................................................... 44

Gas pressure sensor .................................................................................................................... 44

Switch / buzzer / fuel gauge unit ................................................................................................ 45

Gas level sender .......................................................................................................................... 45

Solenoid valves ........................................................................................................................... 46

MAP sensor ................................................................................................................................. 47

Interface connector .................................................................................................................... 47

Injector nozzle to manifold fitting. .................................................................................................. 48

MAP ................................................................................................................................................ 50

Reducer to injector solenoid LPG pipe ............................................................................................ 51

Reducer cooling system feed .......................................................................................................... 52

Top reducer hose ........................................................................................................................ 52

Bottom reducer hose .................................................................................................................. 53

Bleeding ...................................................................................................................................... 54

Filler nozzle examples in use ........................................................................................................... 55

Gun type filler ............................................................................................................................. 55

The other filler ............................................................................................................................ 56

Lessons learned .................................................................................................................................. 57

Filler mount..................................................................................................................................... 57

Tank size ......................................................................................................................................... 57

Tank orientation ............................................................................................................................. 57

Injector solenoid mounting ............................................................................................................. 57

Wiring ............................................................................................................................................. 57

Fuel (petrol) injector wiring ........................................................................................................ 57

General wiring ............................................................................................................................. 58

Wiring conclusion ....................................................................................................................... 58

Background Modern LPG conversions are a good way to retain the performance of a large engine petrol car but

with the equivalent running costs of a diesel or small car.

The basic options are as follows:

Take the vehicle to a specialist for conversion.

o Pro – hassle free, no tools required.

o Con – requires more money, not necessarily true if you do not have the required

tools or skills.

Purchase LPG equipment and fit, setup and calibrate.

o Pro – cheapest option.

o Con – requires conventional tools, effort and experience of setting up LPG, laptop

and appropriate interface.

Purchase LPG equipment from a reseller that is prepared to brief you on the equipment and

includes returning the car to them for setup and inspection.

o Pro – Medium cost, benefit from professional inspection and setup, and receive

appropriate certificates.

o Con – requires conventional tools and more running around. No laptop or interface

required*.

Purchase a vehicle with LPG already fitted.

o Pro – Minimum effort and someone else will have borne the brunt of the costs.

o Con – LPG is relatively rare so it may be impossible to find your chosen car with it

already fitted.

This document only covers the third option.

*Note: I supplemented the third option with my own laptop and purchased an interface. I also

installed Windows Media Encoder to capture the whole setup process for reference.

Cost Benefit Analysis I chose LPG based on the following factors:

An expected reduction in fuel costs of approximately 30% - 40%

Break even on the purchase in <8 months

The logical conclusion that the cost of fuel would go up year on year

Tools These tools are required:

Comprehensive general tool collection, not limited to:

o Assorted sockets

o Assorted spanners

o Clic/Clic R hose clamp pliers

I purchased 040214231 from Machine Mart

o Large flat blade screwdriver

o Torque wrench(s)

Job specific tools, not limited to:

o Soldering iron, solder, and heat shrink

o Spring compressor

o 5mm Drill bit

o 6mm Tap

o Flexible drill drive

o Grinder

o Welder and consumables / safety equipment

o Steel / Aluminium sheet

o Rivet gun and rivets

Garage equipment for raising and supporting the car

Safety equipment, such as but not limited to:

o Eye protection

o Dust mask

o Gloves

Knowledge base:

o LPG kit parts literature

o Supplier that provides phone or email support

o I personally collected the kit so the supplier could talk me through the parts and how

they fitted together. It is surprisingly simple. As it happened he had a converted 525

on site which was nice to see

Parts list o LPG Kit

o Steel sheet and optionally Aluminium sheet

o Rivets / Screws

o General wiring consumables.

o Other – there are always a load of bits and bobs required, for example I used part of

a Vectra cooling system hose to improvise coolant pipes to the reducer / heat

exchanger.

Design decisions The pros and cons of some component selections are below. These are laid out to aid in the choices

and also to show how someone else would select different parts depending on their vehicle /

application.

Design decision 1 – Tank Option Pro Con

Cylinder in boot space

Larger capacity tank easily accommodated

Full size spare retained in original location

Increased range

Boot space compromised

Split rear seats may be obstructed

More complex mounting

More complex connections to filler

Raises centre of gravity

Toroidal in spare wheel well

More boot space available

Split rear seats still clear

Simple fitting*

Simple connections

Reduced range

No spare or reduced luggage space Note some may find a can of tyre repair an acceptable mitigation

Based on the above a toroidal tank was chosen and a compromise on boot space achieved with the

purchase of a second user 16” space saver to minimise the amount of boot space used.

*Note: Some later cars may have the fuel tank carbon canister situated under the spare wheel well

which would require re-location or a different design decision outcome.

Design decision 2 – Filler type and location Option Pro Con

Panel mounted Convenient and clean position

Unlikely to be damaged in a collision

70mm diameter hole required in panel

Black, cannot be colour coded

More complex mounting

More complex routing to tank

Battery box and exhaust back box inhibit routing to a toroidal tank if mounted in either quarter

Bumper mounted Does not require cutting an expensive panel

May be damaged in collision

Complicates bumper removal

Requires clearance behind bumper

Must comply with COP11 clearance from exhausts

Under bumper central mount

No panels are cut to enable fitting

May use a pump on either side of the car

Simple connection to tank

Less likely to be damaged in a collision

Must comply with COP11 clearance from exhausts

May be inconveniently low

Based on the above an under bumper filler was chosen

Procedure

Mount tank It should be noted that LPG is a heavy gas and does not easily disperse. The design of the toroidal

tank and its fitments are such that all the bolt holes and screw holes and cover have rubber seals to

ensure that any gas leaked or “blown off” by the pressure release valve is safely vented under the

vehicle onto the floor where it can disperse. To this end the vent tubes need to be a good fit in the

floor and protrude far enough below the vehicle.

The mount for bolting down the spare wheel would not allow the toroidal tank or its vent tube to be

easily fitted or a good seal. Therefore the sealer was removed from above the seam in the spare

wheel well and the mount twisted anti-clockwise to remove it. Two flats are provided on the

trumpet part to allow this to be easily done with a big enough spanner.

I did consider getting another spare wheel mount to modify and storing the old “colour coded” one.

However, I decided that the likelihood of removing the kit was low, that another mount could be

acquired in future if required and modifying the existing one reduced expense and effort.

The removed spare wheel mount.

Test fitting of bare tank once the spare wheel mount was removed.

Spare wheel mount modifications start here. The original mount is modified to capitalise on its easy

removal and refitting to allow the conversion to be reversed with minimum work if required.

Note: If a welder is not available a circle of 3mm or 4mm steel plate could be used for this purpose.

Pilot hole drilled and trumpet removed with a nibbler.

A grinding disk made a nice template for drawing around, the disk of steel was cut out with tin

snips....

....and then clamped in place. Note that the vent tube is fitted into notches cut in the wheel mount

and new disk that together make a hole. The position and size of which were marked from a cereal

box template of the middle of the LPG tank.

Then the middle was tack welded.

This is the mount placed on the centre of the tank to make sure all the holes are in the right places

before seam welding.

Disk seam welded into the spare wheel mount and the two reinforcing tags provided with the tank

welded to it. These tags are provided to mount the tag to a flat spare wheel well floor.

Two “generic self grip wrenches” used to twist the mount into place in the floor.

Mount in place ready for the tank.

Note: Before the tank was finally bolted down the filler mount was fitted

Tank loosely bolted into place to check fit. When the tank is properly fitted seals are used under the coach bolt heads, and O rings under the vent tube and vent tube fixing screws to ensure any gas vents under the floor and not into the spare wheel well and battery area.

And allow for adjustment of the vent tube length.

Multivalve installation into the tank Once the tank is securely bolted down the multivalve is fitted. The float is held in line with the “fill

level tube” and the flexible LPG pick up pipe is held together with them. Avoid the common error of

hooking the LPG pick up pipe over either of the other two.

The multivalve should be installed in line with the manufacturer’s instructions provided with it. The

bolts in the tank threads are discarded; they are only provided to protect the threads and are not

intended to secure the multivalve. The multivalve packaging contains more bolts. A torque wrench

may be needed here.

Mount filler If I remember rightly the COP11 regulations specify that the filler mount should be able to withstand

more than 50KG. They do not, however, specify that any panel it is connected to should.

It should also be noted there are two types of pump “nozzles”, those similar in appearance to the

traditional petrol or diesel nozzle and some where it is more like a fireman’s hose with an arm that

flips forward and hence requires more panel clearance.

The information I was given for mounting an under bumper filler was that most are mounted at the

bottom of the bumper and that there should be 6” clearance all around. As the bumper curves under

mounting it on the boot floor back edge would not provide 6” clearance all around making these

appear contradictory and exclusive instructions.

I wasted one day thinking about this and finally decided to make a mount that provided 6” clearance

all around from a couple of inches behind the gas bayonet filler and was adjustable without

removing the tank in case I made a mistake.

I purchased approximately 300mm of 50mm by 3mm wall box section.

Various cuts are made to the steel. Cutting at an angle, to make it less likely to get hooked on

anything, and then cutting a wide slot in the remainder of the bottom to allow good access to

tighten the compression joint.

The brass bayonet filler came with a steel L shaped bracket, the short side of the L to allow it to be

screwed or bolted to a suitable place was sawn off and I welded the remains to my bracket.

Shown below with the brass bayonet and plastic trim fitted.

Shown below is the same bracket with bayonet removed and holes drilled to make its positioning

adjustable,

The mounting bolts are spot welded to steel oblongs for two purposes. This spreads the load of

securing the filler bracket to the boot floor making it more secure and able to take a bigger load and

stops the bolts spinning as once the tank is in place they will not be readily accessible if the bracket

is moved.

Paint applied. You may be able to see a 5mm hole drilled in the bottom right corner of the filler

bracket.

Various articles on the web spoke of allowing a coil of pipe to allow slack in case the filler is damaged

in an accident so as to protect against damaging other components so I allowed a loop as this would

also accommodate if the filler bracket was moved fore or aft later.

The rubber sleeve is stripped from the pipe at both ends and olives used where it connects to the

multi-valve and brass filler. This is basically a compression fitting for those familiar with plumbing.

A hole was also drilled in the filler cap and two zip ties used to create a tether to stop it being lost

The finished filler and cap are shown in place. Note the lugs on the bayonet are East and West not

North and South.

Multivalve shown with the filler pipe on the left and the front to rear pipe on the right.

Note: I wasted about a half a day trying to bend these pipes to line up with the multivalve. In the

end I bought a Clarke CHT264 from Machine Mart which allowed me to get the pipes near enough to

apply some adjusting force by hand to finally fit them.

Rear to front LPG line The COP11 rules state that pipes should be secured not more than 60cm apart under the vehicle. As

I was not going to strip the whole interior out I slid some brake pipe down the drill to make sure it

went just through the bodywork without going far enough inside to cause damage to trim etc.

I removed the near side rear spring to allow access to route the front to rear pipe and make sure it

would clear the suspension throughout the full range of movement. I lost about ½ a day due to a

stripped locking wheel nut.

Heat shield mount doubled as pipe securing bolt. The front to rear pipe left the multivalve, out of

the vent tube, and up the side of the spare wheel well................

..........then around the outside of the subframe mount but above the anti-roll bar mount

.....and up the inside of the chassis box section.......

........ because I had found that when the car is on the bump stops if it was on the bottom of the box

section it would be crushed.

The pipe then has to come across to the outside to go around the petrol tank..........

...........and above the rear trailing arm. Clearance still exists with the car sitting on the bump stop

The plastic shield is removed from the corner near the tank to allow the pipe to be routed and

secured.

And trimmed..........

........and refitted.

A simple screw replaces the sheared stud and nut that fixed the shield in place.

And the pipe bender came in handy again as the LPG pipe joins the run parallel to the brake and fuel

lines.

And continues along the floor behind the fuel filter cover and up into the engine bay closely

following the line of the fuel pipes until it deviates to connect to a solenoid mounted with the

reducer.

Solenoid valve and reducer mounting I assembled the front solenoid and reducer onto a bracket and piped them together.

The complete assembly was them bolted to what would be the battery mount on a 1.8. The open

fitting on the left of the solenoid is where the front to rear LPG pipe will connect.

Injector mounting Note: these are essentially solenoid valves if my understanding is correct.

Mounting of the injector blocks depends on the type you have. The chosen location complicates

changing coils or spark plugs and is not ideal. However, the injector blocks lift away after undoing 4

nuts so it is a minor inconvenience.

A bracket location was chosen and marked on the cam cover trim.

I am not a fan of using this thin plastic as a mount so a plate was also fitted on the inside to spread

the load and ensure the mount was rigid.

A view of the inside of the cam cover trim showing the reinforcing plate.

Cam cover trim refitted to the car. This would not be the only time it was removed and refitted.

Here you see the solenoids mounted on the bracket. Note the wires for the pressure sensor near the

oil filler cap.

Each block is capable of fuelling 4 cylinders, so two are used and two solenoids will be left unused. I

must point out that various solenoids are available in singles and threes as well. However, four is

likely to be the cheapest and most readily available and I choose to see having two ”spares” built in

as a bonus

Each block is mounted on two rubber bobbin type mounts that screw into the base plate and are

then bolted to the bracket.

In this picture you can see the short length of LPG pipe and hose clips securing the two together in

series.

MAP sensor mounting With the fuse box lid removed the relay cover was lifted away and the MAP sensor mounted with a

self drilling self tapping screw. Obviously this relies on a relay location being free. However, this is a

small sensor easily mounted elsewhere.

ECU mounting The ECU provided can be mounted anywhere dry in the engine bay, preferably with the wiring

connector at the bottom. However, due to various options a good mounting space was not as easy

to find as expected so it was decided that it would be piggy backed in the standard ECU space.

Note: This space is already occupied by an ECU for the gearbox in automatic transmission models

Sound proofing is removed then 5 screws are undone to remove the cover panel to expose the

standard ECU.

With the wiring disconnected the ECU slides out.

There are a few pictures missing here but the steps are as follows:

The ECU mounting bracket was removed, to do this I had to cut a spanner in half for

clearance

Once removed the mounting bracket looks something like part 6 in this image. The top and

half the height of the nearside were removed.

An aluminium plate was cut to size and then riveted to it at half height

The LPG ECU was then screwed to it.

Part 11 in the image was trimmed to allow the wiring to exit into the heater area.

The ECU mounting bracket was refitted to the car with the LPG ECU already attached

o Note that there is a round grommet in the back of the ECU space. This was used to

pass the wiring for the LPG gauge and on / off switch into the interior of the car

entering the passenger compartment behind the glove box.

Here you can see the wiring passing through the cut out in part 11 and back in to the engine bay.

Cable armour is added.

Here is another view showing the wiring leaving the ECU compartment and curving around into the

engine bay. The black fuse block is just visible.

Note: The fuse in the wiring loom is not ideally placed as it is now in the heater box area on the bend

before it enters the engine bay.

Wiring

Overview

A brief description of the wiring and its connectors will help before going further. A wiring diagram

can be found here.

Here is a brief summary in my words:

Permanent live

o Has a convenient ring terminal, which may have been changed for a larger size, and

was attached to the large live connection in the side of the fuse box

Permanent earth

o Has a convenient ring terminal and was bolted down under the earth pin near the

nearside turret

Ignition live

o There are obviously a load of places this could be picked up. I chose Pin 16 of the

X6002 connector – the “old style” diagnostic socket on the offside turret

RPM feed

o This was taken from coil number 2 on advice of the supplier of the kit.

o There are three wires to each coil, two of them are the same colour on every coil,

and the different one is the one required. This was traced back to the connector

under the diagnostic socket and the new wire wired into the “car side” of the

connector so that the coil wiring could still be unclipped if required

LPG injector connectors

o 6 multi plugs, each with 2 wires in and numbered 1 to 6

o These can connect to any socket on the injector block but the LPG pipe from the

injector to the manifold has to feed the cylinder with the corresponding number

Petrol injector connectors

o These are numbered 1 to 6

o Each has a male and female injector type socket

o The car’s loom connector is unclipped from petrol injector number 1 and the male

connector of the “number 1 pair” connected to it.

o The female connector of the “number 1 pair” is then connected to the cylinder 1fuel

injector

o Repeat for the other 5 injectors making sure the numbers always align

Lambda sensor wires

o These are optional

o Two are provided which is exactly the right number for a 328

Reducer temperature sensor

o Two wires on reducer

Gas pressure sensor

o Two wires on the end of the injector block nearest the oil filler cap

Switch / buzzer / fuel gauge unit

o 5 wires all colour matched

o Ran inside car to a convenient place, in my case the unit is fitted into a switch blank

by the cigar lighter

Gas level sender

o 2 wires

Solenoid valves

o Two wires from the ECU loom

o Connected to two solenoids, one front and one rear wired in parallel

MAP sensor

o Nice and easy, there is a connector block on the wire to fit it

Interface connector

o Used only during setup

o Tucked away into the ECU compartment when not in use

Permanent live

The fuse box lid is removed, then the permanent live can be bolted down. The original ring terminal

was cut off and a bigger one used.

Permanent earth

A suitable existing earth point was used to bolt down the permanent earth ring terminal.

Ignition live

The rubber boot was peeled back and some insulation carefully stripped from the wire attached to

Pin 16 of the X6002 connector. The RPM wire was slid under the existing wiring boot so no

additional holes are required. The RPM wire was wrapped around this wire and the two soldered.

Electrical insulation tape was applied and the rubber boot replaced. Cutting the wire in the car loom

or dismantling the socket to slide heat shrink on was deemed too big a use of effort for the extra

return in quality.

RPM feed

Of the three wires that are connected to coil no2, the one whose colour is not present on any other

coil, was traced through to the multiplug and traced across into the car side of the loom. A wire was

then attached to using the same method as described in the paragraph above.

LPG injector connectors

These are simple 2 Pin push on connectors, numbered 1 to 6. Be sure to connect number 1 to the

injector solenoid that feeds cylinder1 and so on. Note the solenoids have been rotated 180 degrees

in relation to the base so the wiring can come from a better angle.

Petrol injector connectors

The standard wiring connections that push on to the 6 petrol injectors are the typical two pin

connections. However, they are pushed into a plastic conduit from below and held in place by a

square section rubber band and then wired from above. The same conduit contains the lambda and

vanos wiring.

This is the only location where the LPG kit interferes with the operation of the standard fuel

injection. Therefore I chose not to modify the standard car wiring to the detriment of appearance

but to allow the LPG to be easily unplugged if required in the future for whatever reason i.e. to

eliminate it during fault finding or transfer it to another car as just two reasons.

The vanos wiring was disconnected from the front end of the conduit and the clips, which are very

awkward, released to allow the conduit, with injector connectors in it, to be lifted up. The conduit

was cut away to leave only the connectors.

Note: I could have de-pinned the connectors, however, I figured that I would not be reusing the

conduit and that with 12 pins there would be a chance of introducing a fault.

The LPG wiring for the fuel injectors consists of 6 pairs of male and female connectors. Simply put

the standard wiring, 1, comes off an injector and connects to the LPG loom, 2, the other terminal on

the LPG loom, 3, pushed onto the injector. The LPG injector wiring pairs are numbered 1 through 6

and line up with the appropriate cylinder number.

Lambda sensor wires

Two wires are provided for monitoring the lambda sensors. I was told connection of these is

optional.

One wire was connected to the black <check> wire from each lambda. They were connected in the

same manner as the RPM and ignition live wires were.

Front sensor wire.

Rear sensor wire.

Reducer temperature sensor

The temperature sensor wires are shown here taped to the reducer to avoid them being pulled in

installation.

Connection to the LPG wiring loom was a straight forward process. This was a case of stripping the

sleeve off all four wire ends, tinning them, sliding the heat shrink back on two of the wires, sweating

the joints together then sliding the heat shink down and heating it to shrink it in place.

A good picture of a similarly constructed joint is that below in the gas pressure sensor section.

Gas pressure sensor

If I remember rightly I had to cut a connector off the Orange / Black wires. Barring that this was a

straight forward task using the method described in the section above

Switch / buzzer / fuel gauge unit

Glove box was temporarily removed to access the grommet on the rear of the ECU space and route

the wire bundle to the gear lever area. A hole was made in one of the switch blanks to allow the

switch wiring to be passed through it and the switch mounted. All wires are married up colour to

colour with a minor deviation for the buzzer that indicated “gas out”

Gas level sender

The level sender is held in place by two screws. I was advised to use the top left and bottom right

mounting holes. The provided wire then clips in and follows the rear to front LPG pipe to the engine

bay, zip tied regularly to secure it. However, securing it at the same time as the wire from the rear

solenoid will save some time, effort and zip ties.

Solenoid valves

The front, engine bay mounted, and rear, tank mounted, solenoids are wired in parallel and

connected to the two wires provided on the ECU loom. I hope the stylised image below makes this

clear. Note the red and black “wires” shown are not representative colours.

As you can see the picture below does not really help too much due to the angle and clutter.

However, in reality this was one of the easiest wiring tasks.

The wires from the rear solenoid, zip tied to the LPG line, enter the engine bay here. The one from

the + rear terminal is twisted together with the + for this purpose in the LPG loom and then both

together are slid into a female spade terminal and crimped into it. This is slid onto the + terminal of

the front solenoid. Repeat for the wires for the – terminals.

MAP sensor

MAP sensor wiring consists of a single three pin connector pushed straight on.

Interface connector

Unless setting up the car yourself the only real requirement here is for the connector to be safe,

clean, dry etc and to know how to access it.

Injector nozzle to manifold fitting. I decided to fit the nozzles into the manifold without removing it. This be may frowned on due to the

possibility of swarf getting into the engine. However, it’s a plastic manifold not steel or alloy and

quite soft. Plus drilling with constant pressure means the plastic was removed as two complete

swirls so I’m happy enough. Warning – foreign matter in the inlet manifold may damage the

engine.

If I remember rightly I drilled the manifold 5mm and tapped it 6mm. To get access to drill with the

manifold in place I bought a flexible drive. Note the use of some pipe on the drill to stop the drill

going in too far.

A tap was wedged into an extension to be able to reach the holes drilled in the manifold

All the nozzles were fitted at the same point in the inlet, front three pointing one way and rear three

the other. The centre two are slightly offset on angle to make sure the pipes aren’t bent to any

restrictive angles.

The nozzles must not be over tightened or the soft plastic threads with strip.

The pipes are cut to the same length and armoured where they may rub on anything. They are

secured with the clips provided with the injector solenoids.

It goes without saying but, the solenoid connected to the no 1 wire is piped to the nozzle in the no 1

cylinder runner.

MAP The map sensor has one wiring connector and two pipe connectors. The wiring was covered earlier

Purple represents the LPG gas pressure pipe from injectors to MAP sensor. Green represents the

vacuum pipe from inlet manifold to MAP and reducer via a Tee piece.

Bottom left shows the outlet on the second set of injector solenoids blanked off with a short length

of pipe with a bolt inserted in the end.

Reducer to injector solenoid LPG pipe The dotted purple line shows the path of the large bore LPG pipe from the reducer to the injector

solenoids. The pipe is armoured anywhere it may rub and passes under the heater / wiper area.

The inset shows detail of the LPG filter and reducer connections.

Note: The LPG filter is marked as directional.

Reducer cooling system feed

Top reducer hose

In spite of having some coolant hose supplied I used some sections from this old Vectra hose. The

reason for this is simple, generic hose is straight and can only do sweeping bends without kinking. I

needed to be able to introduce a 90 degree bend in a confined space near the twin heater valves.

There are no good pictured for this so a description will have to do.

The hose from the back of the head to the two heater valve solenoids was cut. About a ½” of tube

was removed and another Tee piece inserted with the extra outlet pointing down. A piece of Vectra

hose 8” long with a 90 degree bend on the end was cut. The bend on the end was fitted to the tee so

that the long end pointed under the heater valves towards the reducer. 3” of copper pipe and two

hose clips were used along with some more of the new coolant hose to extend this to the reducer.

Bottom reducer hose

Simplest of the two hoses, the bottom hose is routed in one piece, using sweeping bends, from the

reducer to a Tee piece inserted in to a cut made in the original hose from block to radiator.

The hose length and cut in the original hose was all carefully done so that the hose will not rub on

any sharp edges and at rest or in movement it does not touch anything hot or sharp. If it had

touched anything that can damage it I would have added armour.

Bleeding

By plugging the ends of the heater hoses while working on the system I lost less than a litre of

coolant. With the car topped up, heater on and front of the car raised (my sloping drive helped) the

system was bled through the bleed screw in the top of the radiator.

Filler nozzle examples in use Note: Read the specific instructions on the pump. However, the basic processes are as below. Be

aware that failure to follow all safety precautions could easily result in freeze burns.

Gun type filler

More like the traditional petrol pump from “back in the day” when you could click the trigger back

and leave your car fuelling until the automatic “cut off” kicked in.

These have a barrel that has a cut out end to align with the two bayonet notches on the filler on the

car. Slide on, twist clock wise, pull back the trigger and then push down the little clip to lock it in

place. Then retreat to the pump to push down the big button to fill.

Removal is not quite a reversal of the fitting process. Do not touch the barrel. Squeeze and release

the trigger, there will usually be a spurt of gas, this is normal. After this rotate the barrel and remove

the filler nozzle.

The other filler

This type the handle is raised at 90 degrees to the nozzle centre line and held vertical. The nozzle

slides on the cars bayonet, handle is rotated 90 degrees clockwise on the axis of the nozzle then

pulled back. The position of the handle when vertical is 1” behind the bumper. It is primarily for this

type that my filler is extended slightly back from under the car.

Removal is not quite a reversal of the fitting process. Do not touch the barrel. Flip the handle

forward, there will usually be a spurt of gas, this is normal. After this rotate the handle upwards until

vertical and remove the filler nozzle.

Lessons learned

Filler mount The filler mount could maybe have protruded 1” less and if I only ever used the gun type filler, which

is the case 90% of the time, it could have been tucked further under.

The central filler saves time waiting for a free spot to fill time and again, as often there are only one

or two LPG pumps on a station and they share lanes with petrol and diesel pumps. Being able to fill

on either side is a benefit.

Tank size When I originally planned the conversion I passes an LPG station on the way to and from work each

day, so I merely chose the largest that would fit entirely in the spare wheel well. Range is 185 to 225

miles, typically around 200 miles. Having changed employment to a round trip of 104 miles a day I

now find the tank covers 2 days. A 20% larger tank would have raised the boot carpet by approx 1 ¾”

but not have allowed me to complete a third day’s trip without refuelling so while a bigger tank

looks appealing, at least at present this one is best fit.

Tank orientation I fitted the tank with the valves at the front as the boot floor slopes forward. The inspector pointed

out that I may get more miles on the flat that way but be more prone to fuel surge when

accelerating hard. He was correct, however this is only noticeable if I have less than 20 or 30 miles

left in the tank and I could always switch to petrol if anticipating dramatic acceleration.

Injector solenoid mounting Mounting the solenoids further towards the middle of the cam cover and / or fabricating a custom

bracket would allow me to tilt the injector pipes down towards where they cross the edge of the

cam cover. Along with slightly shorter and tighter curved pipes this would allow the injector plastic

trim to be refitted with only slight trimming to the side. However, as much as I would like to

improve the cosmetics the pareto principle prevents me from revisiting this.

Part of me would like brackets TIG welded to the cam cover and the plastic trim cut back to ease

access of the coil packs and plugs. However, that is not an option for the reasons already mentioned.

Wiring

Fuel (petrol) injector wiring

It occurs to me that I could have cut the side out of the plastic that previously mounted the fuel

injector electrical connections and slip the LPG loom connectors in so as to keep the petrol fuel rail

wiring tidier.

However, it also occurs to me that had I not wished to keep the kit transportable, that because the

ECU is next to the cars DME, the fuel injector wiring could have been cut into by the ECU

dramatically reducing the bulk of wires across the front of the heater area and preserving the

original wiring and its plastic ducting on the fuel rail.

General wiring

A logical extension of the point made above, about the proximity of LPG ECU to DME is that the

ignition live, RPM feed, main live and earth connections could all have been handled within the DME

area reducing external wiring.

It would have been unnecessary extra effort, but the interface connector could have been re-routed

to the glove box for increased ease of access.

Wiring conclusion

Based on my level of experience, and desire to be able to easily bypass the kit at the roadside / keep

it transportable to another vehicle the existing wiring arrangements were the correct choices made

with the information available at the time.