Problems LPG after engine change from 3.5i V8 to 3.9i V8

Hi, I have a very early LandRover 110 V8 on a Y plate first time round with a BRC AT90E LPG system on it. It used to have a 3.5 V8 engine converted from its original carburettors to injection, but keeping the points type ignition. But now I have replaced the 3.5 engine with a Range Rover 3.9i engine, non cat type/electronic ignition & a hotwire type air flow meter. It will start but not keep running & I keep losing the signal & spark & also am losing my marbles over it.

Not sure if I need a signal booster/amplifier etc; Any ideas please anyone?

So does anyone have or know where I can get a wiring diagram for the LPG system.

It has run fine on LPG for the last 9 years.

did you change the coil? Im sure a "points" coil is different from an "eletronic" coil

Yes the coil & distributor are from the 3.9i engine.

Have seen a few dizzy connectors f8ck up....the rubber thing with 2 wires at 90 degrees to each other that attaches to the wee module on the distributor. you can cut it off and replace with terminals, just make sure the wires are the right way round.

Some old "points" things had a feed to the coil with 12v from the starter to make sure there was plenty voltage for starting, you checked there's power when your not cranking it over.

has it done this since fitted or just come on and ran fine for a bit before

Hi 2 Horse,

The title of your post suggests that you think you have an LPG problem but little of the information provided (to date) supports this. Most people have focussed on the dizzy change as a possible cause and this may well be correct but you could help here by answering one simple question. Does the car run ok on petrol and die when you switch over to gas?

If the answer is yes, the problem aint the ignition. If no, it probably is.

If it is the ignition at fault, I suspect that EeEK has the right answer in that the electronic ignition needs a 12volt supply whereas the original 'points' system utilised 12volts for starting and then 6volts when running. You can check this by running a temporary 12volt feed from the + on the battery to the + on the coil and start the engine. If it now runs as it should, you have your answer.