Thread: Fuel Injecting a Series Landrover

Hi All,

I have been promising for a while to put up some details of the fuel injection that I have put on my Series 3 Game.

I had to change the starter motor after playing in the mud down at Levuka over the Australia Day weekend and to get the starter motor out I had to take the extractors off and to get the extractors off I had to remove the airbox so it seemed like a good time to take a few photos.

First though I will run through what I put together. After a lot of research I decided to use a Megasquirt ECU, these are a DIY ECU that you can build from a kit or get someone to build for you and there is a lot of information available, lots of programs for tuning and lots of options on the build. There is a very active online community for keeping the firmware current and for bringing in new options, in fact almost too much as it can get confusing. I got mine built in the UK by ExtraEFI, the guy there is one of the authors of the Extra firmware that gives most of the useful options. The version I got is a Megasquirt 2 running the MS Extra firmware and is set up to run from a 36-1 trigger wheel. I am also using it to control the ignition directly through Coil on Plugs (COPs) so it includes the drivers for the coils in the ECU. The injection is batch fired and the coils are running in wasted spark mode, if you want sequential you have to have another trigger that runs off the cam rather than the crank and the benefits did not stack up with the work required on that one .

The actual hardware I have used is individual throttle bodies from a Honda CBR600RR motorbike with injectors in the throttle bodies and the COPs from the same bike. I used the injectors from the bike since the horsepower output seems to be the best way of sizing injectors and the bike get about 118 HP at around 12k RPM so I figured that there would be more than enough fuel for the series engine with 82 HP when new. This seems to have worked out as I have no issues with it leaning out up the rev range.

I tried to use a trigger wheel bought from ExtraEFI but could not get it to fit properly so I had one laser cut here to my specs. I have a capstan winch drive on the front of the pulley so the wheel had to clear that. It is bolted on to the crank pulley (drill and tap holes) and I then had it run in a lathe to make sure it was perfectly centered. The sensor is a GM VR sensor and I had to make a mount that sits between two of the front cover bolts and allows some adjustment so as to get the clearance perfect.

The other sensors used are engine temperature, intake air temp, throttle position and manifold air pressure (MAP). Engine temp caused some problems because I could not get a proper mapping of either the standard sender or the external bolt on sender I tried so had to replace the standard sender with a GM one that the mapping already existed for. MAP can also be interesting as the four throttle bodies never really give constant readings, particularly at idle and low revs. This is catered for in all the varied programming available for the ECU though.

The throttle bodies as fitted to the bike are two units with two throats (basically like two dual throat carbies) that are joined together with the throttle control in the middle. I had to separate these two units and move them slightly further apart to match the ports on the series engine so there was a fair bit of amateur fabricating to make intake manifolds, longer links between the throttle bodies and then to make throttle linkages and a link to the idle air control with the choke cable. I was able to retain the standard throttle linkage with a spacer to bring the final connection out from the inner guard more underneath the throttle bodies. Many thanks to Killer (Mick) from this forum who helped with the loan of a spare head for test fitting and cutting out plates and welding for me on the inlet manifolds and other bits here and there.

Because of the need to separate the throttle bodies I also had to get new fuel rails made up and these were done down in Melbourne and work perfectly.

There seems to be a fairly long list of extra bits now that I am actually thinking about it . Because the standard series has a mechanical lift pump and no baffling in the tank I also needed an electric lift pump, low pressure filter, expansion tank, high pressure pump, high pressure filter, fuel pressure regulator and lots of good quality high pressure line and clamps. The fuel pumps and expansion tank sit on the chassis rail behind the gearbox so if you lift the center seat panel you can see them there. There is also a wideband oxygen sensor in the exhaust and a TechEdge controller for that linked into the ECU. Oh and of course a custom air box, which took four tries to get right, it uses the standard oil bath air filter.

Also because the series has not got a lot of electrical stuff standard every bit of wiring had to be added. I have positioned the ECU on the inside of the firewall and run the wires through from there, the relays and fuses are all on the engine side of the firewall. The Megasquirt ECUs are very fussy about their wiring and making sure that there is no generated noise from poor earths and such like so a lot of effort was put into making all the connections good quality and a common earth bus was attached to the engine to get that side of things sorted.

I no longer need the distributor to control spark but have left it there to fill the hole. I may possibly use it later as the extra trigger for sequential park and injection but honestly I don’t think it is really needed for this application.

So that is the hardware but involved in this, as I am sure you can imagine, was six months of work from when it came off the road till it first started (and it started the first time I turned the key). There was also an engine swap, after the first start, as I discovered very low compression in the front two cylinders, and there was a lot of tuning and set up after it was first running. There has also been a gearbox rebuild and the adding of an overdrive and a complete new exhaust system. But I can now sit on 100kmh towing a trailer with the camping gear in (until I hit a hill at least) and it is generally a pleasure to drive compared to what it was.

The tuning software I am using is TunerStudio and it runs on the MacBook Air I have, it’s a bit surreal in a 35 year old car to have a laptop sitting on the seat showing you everything happening in the engine and doing live tuning while you are driving along, but fun ☺. Next up is probably an Android tablet running the software that can sit up on the dash and give me a heads up display on the windscreen while driving.

I want to rebuild the original engine now and perhaps do some performance mods to the head in the process and then see how it can really go.

Ok, you have stuck with this story for that long the photos will be in the next post.


Cheers,

TimJ.

There really isn't a lot of power difference overall, I have had it on a dyno and it came up at 62hp at the wheels which is not bad from an engine that has 82 at the flywheel when in perfect condition. Since then I have retuned it quite a bit and it is going better. With the carbie I was changing into third gear up and over the gateway bridge, now I just go over in 4th. But the biggest difference is in drivability it is much smoother and has more power in the midrange than before. Also the main reason I did this (apart from a desire to do something different ) was to get rid of the problems I had with the carbie off road, due to an incorrect gasket kit it was dieing on hills, particularly if the right side went into a rut. I fixed that with the right top cover gasket but then it started flooding in dips and I just got fed up with it. I got to a stage where I could pretty much pull a Zenith off the engine, pull it apart and put it back together blindfold.

Cost is a bit of an uncertain thing as many of the parts were bought on ebay from the US or UK. The largest single cost was the ECU and sensors which cost me around $750 with the exchange rate at the time and the options I wanted. The throttle bodies, wiring loom, COPS and rubber mounts from the bike cost me around $300 from the US but I have since bought all that plus an original airbox as a spare for $150 delivered so price depends on what is available at the time. I am sure that there would be other throttle bodies that would work just as well and may be cheaper. Other costs were fuel rails, fuel pump, expansion tank, filters, hoses, pressure regulator, oxygen sensor, software, and metal for making brackets and manifolds.

All up probably a little on the up side of $1500, not economical really but a project that I thought was worth doing. On a recent trip up to Manar park I measured the fuel consumption from Brisbane to Kingaroy and got just over 12l per 100 while sitting on 100kph in hilly country, on a trip to Fraser with quite a bit of slow going I got 16.7lph and that included sitting up to 110kph on the way there and back. So considerably better than standard economy but that will take a while to make the difference. It's just much better to drive though, particularly off road and that is what I like to use it for.

Cheers,

TimJ.