V8 Discovery Running Gremlins...

[Crispywombat]

Hi,

I'm a the proud (ish) owner of an 89 3 door 3.5 Disco running SU carbs and an LPG conversion. I'm after some advice. Thle car starts and runs ok on LPG, it does backfire a little but looking at the state of the HT leads, that's no suprise! It won't however run on petrol, it just coughs and farts, it's only done 93k which I beleive to be true and as I say is pretty good on LPG.

While I'm here what are your thoughts on replacement Leads and Plugs?

Cheers,


Rob

[craig_midz]

get geniune parts ie dizzy cap an rotor arm an 8 mm leads an i use bosch spark plugs but with lpg best to use geniune dizzy cap

[Crispywombat]

Thing is it runs great on LPG, just not on petrol, I was wondering if it was a fuel filter or the fuel pump....

[Skibum346]

Could be porous fuel line somewhere letting air in...

[Crispywombat]

I've been out in it today, running on petrol ok up to about 40 ish when it just seems to run out of power, I know the leads and plugs need a change but it does seem to be fuel starvation...not sure how though. I'll take a look at the fuel lines when this snow settles down a bit!

[300TDi Disco]

Petrol can go off after a while have you just been running it on LPG? My mate had this problem with a vehicle. He was just running it on LPG for a while and now it doesnt run on petrol very well. hope this helps.

[Crispywombat]

I just filled up with petrol just to make sure, I only had around a quarter of a tank and added over 60 litres so I'm hoping that's not a factor, just looked at the airbox and it's in a poor shape, so the mixture might not be too clever. Does anybody know about oiling the SU carbs, I'm guessing they haven't been done in a while.

[300TDi Disco]

Think you may have to get the coins out your pocket and give it a full service.     

[Crispywombat]

If it was only coins I wouldn't be bothered!!!! :'(

[Range Rover Blues]

If it runs fine on LPG I wouldn't be looking at the HT ignition, I'd be checking the timing.  LPG is much harder to ignite but that's down to the Octane being about 112-115, so you can run much more advance.  However it won't then start or run on petrol without damage.

More worrying is that on carbs like the SU or Strom you need a piston lifter to hold the SU piston fully open, otherwise the needle runs up and down all the time without any fuel on it, it wears out and goes off callibration.  The SU piston can also screw with the LPG metering.

[Crispywombat]

Well I oiled the SU's and since then she's beeen running like a dream...well almost still backifires now and then on the LPG but I'm replacing the HT's, dizzy cap and plugs and I'll see how she is then!