Installing a Lucas hotwire or airflap EFI system on a V8.I

'll assume you've got a usable V8 rover engine. The vehicle doesn't matter although you should bear in mind that the entry into the throttle body requires some space to the right hand side facing the engine bay and this can be a bit awkward on Defenders and Series vehicles as the inner wings and heater interfere somewhat. It's not impossible to fit but requires a bit of thought when choosing the position for the airflow meter and it's easiest to replace the standard bulky airbox with a K+N or a smaller Range Rover item. I can provide photos of hotwire and airflap installations on these as a guide if needed.

Gains

Depending upon the engine version, you should see significant gains in torque and peak power across the range, however, if you intend to use non-standard camshafts and hotwire EFI you will need to consider getting the ECU remapped. I'll spout on about this later. If you are using an airflap system it doesn't matter what camshaft you use as long as your engine is producing less than 300bhp.

Typical gains on a typical standard carburetted 3.5L engine with output around 155bhp and torque of 200ft/lbs, could see 180bhp and 210ft/lbs with improved starting, economy, emissions, reliability and with more smoothness and tractibility. Engines with ported heads and/or more radical cams will benefit significantly more in these areas, particularly with low speed tractibility on more radical cams. Bigger engines will benefit still more, with standard airflap systems working on engines up to 270bhp and hotwire up to 320bhp albeit with ECU remapping on hotwire systems.

What you need

You'll need the following parts:

Fuel PumpEFI fuel pump, either one of the standard Rover/Landrover in-tank units such as the combined meter/pump unit used on range rovers, or the in-line unit used on Rover 820's, Volvos, Jaguars etc.

The best inline pump is probably either the 603 or 604 models from Eurocarb (Telephone: 0118 943 1180). Listed as replacements for the Morgan Plus8 and LR conversions. The two models either have banjo or hose connections and cost about £100. If you expect to go racing or have an output greater than 180bhp it's well worth considering fitting a rising rate or adjustable fuel pressure regulator for about £60 available from RPI, JE, V8 Developmemts and others.

For 3.9L engines and above I would fit one anyway and set the fuel pressure to 39-40psi. It is also possible to carefully squeeze the existing one in a vice to raise the fuel pressure, but it takes practice and patience to get the pressure right. It's really not necessary to change it on a bog standard 3.5L engine and it will still work ok on a 4.6 but expect the fuelling to be weak at the top end.


Parts List

The complete EFI system comprised of:

Other Parts

You will also need the following tools:


Installation

Removing the existing Manifold

On many older V8's, the two outer bolts at the very rear and front of the manifold can become rather corroded and difficult to remove. There is a real danger that these will shear off if forced, particularly on the rear ones. Usually they will undo a small amount and then bind due to corrosion on the base of the threaded portion of the bolt. The only solution to this is either to shear them off which is a real nuisance to repair, or cut, melt or grind off the ends of the manifold around the bolts and work in some releasing solution and intense heat on the bolt from a welding torch to reduce the corrosion beore attempting to remove it.

Try using releasing oil on it for a day or two first if you run into this problem as you may find it will ease a little with persistant soaking and gentle tightening/untightening. It's a common issue and would also occur if you needed to replace a head gasket or perform any head repairs. It's caused by water finding it's way out of the waterways and onto these bolts and can be prevented by reasonable care in rebuilding. Remenber to drain the water before removing the manifold. The best way is to remove the bottom radiator hose as this will ensure any water remaining is below the level of the exposed intake ports.


Locate the EFI pump

Fit the fuel pressure pump as appropriate bearing in mind that in-line pumps are poor suction pumps and should be at the about the same level as the fuel in the tank. An additional lift pump may be required if the pressure pump cannot be located near the fuel height. On defenders with underseat tanks there is space between the top of the tank and the seat base for this pump and it's a very convenient location. On range rovers it can be clamped to the underside of the load space by the tank or on the top of the rhs chassis rail. A return line is also required. It is perfectly OK to retain the existing lift pump but remember that the new pressure pump must be in the line after the lift pump. IE the lift pump must be connected to the tank and then to the pressure pump inlet. This can be extremely useful if the pressure pump cannot be located near the tank nor at a similiar height.

Fuel Lines

As the fuel line is pressurized at up to 40psi, it is imperative that the correct hose is used for flexible sections and that metal pipe be used wherever possible. 6mm or 1/4" Cu/Ni brake/clutch pipe or 8mm Minibore copper pipe (for plumbing) is suitable for flow and return pipes and the lines should be routed where they cannot be easily punctured. Remember to mark which is which as they enter the engine bay to avoid later confusion and problems.

Install the ManifoldThe EFI system can be fully assembled onto the engine however you will find it easier to fit the engine if the plenum top is removed and you will need this removed to attach the wiring loom to some of the injectors. Examine the inlet ports on the cylinder heads. Later engines have a small raised section in the upper edge to clear the injector spray. If these are not present you will need to add them. It can be done in situ by thoroughly stuffing the ports with rag or paper and masking off the valley area to prevent swarf falling in, then using the valley gasket as a guide, mark out the required shape with a marker pen and cut to size with a Dremel or similiar. The curved section needs to taper into the port about 15mm. Use a vacuum cleaner to remove the swarf and keep the vacuum cleaner by the port as you withdraw the tissue or rag in the port. Now fit the gasket, seals and manifold and torque correctly. Fit the plenum top making sure the joining faces are cleaned and coated with a thin layer of silicone sealer. Connect the petrol pipes.


Wiring

Fit the wiring loom and attach all the connections, noting that some are very similar but can be deduced by colour or free length of cable. You will have two connectors left over, one is for the ECU in the car and the other connects into various circuits in the main loom. There is also a bunch of earth connections which are usually attached to the back of the right cylinder head but may be connected anywhere convenient on the engine castings. The ECU is sensitive to heat and moisture and must be fitted in the interior of the vehicle. Fit all the vacuum, air and water pipes and top up with water and antifreeze. Fit the throttle cable and check the action is correct (fully open to stop, fully closed to stop screw on throttle body). Loom ConnectionsThe EFI loom connector which connects into the main loom has several important connections on it. These are:

+12v switchedignition supply. (ECU Enable)

+12v from battery. (ECU and switched pump supply)

+12v from starter supply. (ECU Reset)

Controlled supply to fuel pressure pump (and lift pump if fitted). There are also one or more substantial earths in the ECU loom which should be bolted to the back of the right hand cylinder head or another convenient point on the ENGINE. Depending on which EFI system you have, there may be several others which can be ignored for the purposes of getting going. The most useful of these are the fast idle signals which are used for controlling the idle speed when an autobox and aircon are used. The aircon signal is handy if you have a winch. There are usually two speed inputs, one of which may be directly to an air valve rather than the ecu on earlier types. Work out where you need to pick up these connections in the main loom, remembering to insert 10 amp fuses in all three supply wires.

Tach signal into ECU

The the tacho wire in the ECU loom (white/black or white/blue)is normally connected to the negative side of the ignition coil via a protection resistor somewhere. It is important the the connection is made on the protected side and not directly to the coil. If no tacho resistor exists then a 10K resistor should be used.

Many Classic Range rovers have a suitable resistor with a spade connection on each end lurking somewhere near the coil. Dunno the part no. but it should be easy to get one. SD1 engines with electronic distributors also had an 6 pin ignition ballast module with an integral protection resistor.

So that's what two of the pins are for! Or you could buy a 10K resistor and stick it inside some heatshrink sleeving with a spade connector on each wire. Up to you. Note that on later airflap models an anti-dieseling mod was done consisting of an ignition operated relay on the airfilter bracket, which disconnects the ECU tacho feed (white/black or white/blue wire) from the coil. This isn't shown on the diagrams.

 There isn't much else to it other than figuring out why it won't work :-(

Troubleshooting the installation

Fuel Pressure

You must have the correct fuel pressure of around 35psi into the fuel rail. It will not work properly otherwise and may not run at all.

Fault Isolation

You can get the thing to start and idle with the airflow meter and throttle pot disconnected.  This might be helpful in diagnosing faulty components.


HotWire AFM

Hotwire EFI types are extraordinarily sensitive to turbulence before and after the airflow meter. If the pipe into the meter has a bend near the meter, it may not idle well and may cause flat spots as the main flow moves around at different rpm. Avoid sharp bends behind the meter for the same reason. I

Nterference

All the systems are sensitive to RF, power variations and supply noise. Ignition systems and alternators should be suppressed. Poor earths, faulty batteries, poor power connections and tired alternators can cause weird problems and misfiring.

One cylinder down

If one cylinder won't fire at all or only intermittently, then it could be a faulty or blocked injector or faulty or disconnected injector wiring. On airflap types only, the resistor pack or its connector can fail causing one or more injectors to stay closed.

4 Cylinders downIf 4 (and only 4) cylinders won't fire then the ECU is faulty or the ECU plug/socket or wiring loom is damaged, possibly the injector common wire at the resistor pack. (Its batch fired left bank / Right bank - not each injector individually)

Hot Start/Cold Start problems

Cold/Hot start problems and overfuelling can usually be traced to the boost injector in the side of the plenum (flapper system), the temperature senders or thermotime switch or the starter signal wire from the main loom socket. Starting when cranking but dying when the key is released can be caused by several things.  The supply for the fuel pump orignates from a relay on the ecu loom which is operated by a fuel cut off valve on the rear left hand side of the plenum, by the starter relay supply and via a diode pack in the ecu loom which keeps the pump running once various conditions are met.  

Erratic Idle

Erratic idle is often related to the Extra Air Valve on airflap systems (front left on the manifold) or the Air bypass valve (rear of plenum) on Hotwire systems. It could also be a disconnected airflow meter, turbulent airflow into a hotwire meter, bad earthing on the EFI loom, faulty alternator, low battery or a badly adjusted or broken throttle position sensor.

It could also be a faulty ECU. If the cam is a performance type, erratic idle may be a consequence of long valve duration. The usual cure is to raise the idle revs or live with it. Most street cams have a smooth idle but anything from "214" up may have a choppy idle below 750rpm on any engine, particularly smaller ones (3.5L).