Range Rover P38 LPG conversion

Range Rover P38 LPG conversion

Naturally a 4.6 litre P38 Range Rover isn't the cheapest vehicle to run, so I decided that an LPG conversion was the order of the day. Being slightly practical, I decided to do the conversion myself. This gives two benefits:

I did a bit of research and determined that an OMVL Dream XXI was the system for me. This was mainly based on indications that it doesn't cause the Engine Warning Light to come on

Obtaining the system wasn't entirely straightforward, but I did succeed with the purchase of the OMVL front end kit. I got the tank from Tinley Tech who are just down the road from me, and given the weight of the tank, saved a fair bit in postage!!

For the most part, the install is pretty straightforward. The instructions are badly translated from the Italian, so some components, e.g. 'Regulator compensation' , 'Posterior Gas Solenoid Valve' , 'Collectors of Aspiration' take a bit of figuring out, but it's not too hard....

The biggest challenge was how to fit the LPG injectors to the inlet manifold. There are various schools of thought on this, but my idea was to put myself in Land Rover's shoes and decide how they would have done it if it were a production option. I concluded that they would feed the LPG into the upper manifold as close to the bottom as possible. This gave me a huge engineering challence as although I could envisage how I wanted it done, I couldn't find anybody prepared to do the aluminium welding for me. I did it myself in the end, then dressed it with head-porting tools, then sealed it with an aluminium epoxy (Devcon Aluminium Liquid) to compensate for my lack of welding skills.

Once satisfied that it was installed correctly, I fired it up, calibrated it with the laptop software, and went for a ride.

Then I booked it into Tinley Tech for an inspection, and they made a couple of tweaks to the configuration. Now it's very good, and I'm pleased with the result.

There are two minor frustrations:

1. The gas ECU takes some information from the petrol ECU via the OBD-II port. The upshot of this is that you can't use another OBD-II reader at the same time!!

2. The laptop software lacks certain features unless you have the 'dealer dongle'. I really would like to get hold of one so I can properly maintain my system. Interestingly, the ECU is actually made by AEB, and it's the same one used by a few LPG system suppliers. Unfortunately, the software is keyed to the vendor, so a BiGas dongle won't work with the OMVL system.

Some pictures of the install:

ECU and Vapouriser mounting brackets to fit on top of the suspension damper turrets

Brackets to mount the cables crossing the engine bay on the bulkhead

Fitting the control button / fuel gauge to the dash

Fitting the tank filler to the rear bumper. I have since realised that this will cause me a problem if I ever fit a tow-bar!

And the tank. 95litre volume, 72litre fuel fill.

The LPG system needs a +12 permanent feed, so I decided to take it from inside the fusebox. I initially took both a permanent and a switched feed, but only used the permanent one.

This is the buildup of the manifold:

I reckon it's pretty good, even if I do say so myself!

The Vapouriser sits nicely next to the fusebox

I kept the wiring tidy too, tapping into the main loom near the engine ECU and doing the joins inside the ECU cover

The hope is that it will give years of reliable service. We will wait and see....

All images (C) 2005 - 2015

Last modified on: 23rd June 2015 by email the webmaster

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