Hi everyone, I'm scratching my head with this one so would appreciate any input!
I have a 1996 Discovery V8 Petrol with LPG, every time I drive through a puddle it misfires - doesn't even have to be a deep puddle! I've had a look to see why, I've tried cleaning all contacts, covering with grease all to no avail. I did hear some arcing and when I checked this in the dark I could see this arcing in numerous places on the distributor cap, HT leads and between the terminals on the coil. I have therefore changed the cap/rotor arm and leads which is where I am now confused.
The cap is now clear of any arcing, however the leads are arcing where they are either touching or close to metal and weirdly along my top radiator hose (rubber!). I know it's been a while since I was at school and college but can't believe I've got it wrong that rubber could act as an earth for arcing?
I do still have the slight arcing between the terminals on the coil.
The disco is running fine despite this arcing - any help would be appreciated

The only thing that can will or may cause a problem when you go through a small puddle is the connection plug to the speed sensor. the engine ecu won't like it if it's doesn't get a signal hence the misfire. U may also have notice the speedometer fluctuating.

Sounds you have purchased some iffy plug leads as genuine ones don't 'track' when new.

With the hose tracking, if it was pure rubber it won't, but yours may have some metal in it's makeup as a reinforcement and to help keep it's shape, some hoses now use nylon.

Thanks for the response, where do I find the speed sensor?

it is very important to use quality ignition parts when running on lpg. it sounds like you have either bought cheap leads or they are faulty as Discool says. when running on lpg any ignition fault will show up quicker than when running on petrol.

rrssupercharged said:

Thanks for the response, where do I find the speed sensor?

Click to expand...

You will have to get underneath, sorry, but then u should see a cable going to a unit bolted to the upper side of the transfer box, the unit is a transducer and is fixed to the t box with a single allen headed screw, u will then see the connection plug.. it should have a water proof shroud but remove and clean and replug and hopfully that was your problem.

OK, i've tried replacing the main coil HT lead with an NGK one as this was the main one arcing/tracking - still does the same thing!
I'm thinking that the arcing/tracking between the terminals on the coil may somehow be causing this?
Any other ideas?

can you see any cracks in the coil housing near the shorting? where are you in the country, if you close you can try my coil out.

Thank you for the offer Discomark - much appreciated. I've just bought a new coil which has stopped the arcing/tracking on the coil itself but still have the prolem on the coil to cap HT lead

What make was the dizy cap, might be a crappy one.. go for a blue lucus if you haven't