Thread: Disc 95 3.9 Petrol

What is your ignition timing set to? Stock figures are useless. 10 degrees advance at idle makes a lot of difference.

Also check the ECU temp sensor (2 wire plug at front of inlet manifold near thermostat) shows a lowish (circa 300 ohms) resistance when hot.

Lastly check your vacuum advance is working, they are all getting holey by now. Cheapest replacement is approx $60 ex UK on ebay, 2 week postage time. Replacement diaphragms can be done by Advanced Diaphragm Options in Oz.
advancediaphragmoptions.com/‎

On the highway at 110kph you should get around 14-15l/100km, around down normal driving 17-19l/100km hard driviing around town 20-21l/100km and full offroad 20-25l/100km.

So yes you need something looked at - a full tune up - plugs, leads, dissy cap, rotor (genuine only) maf cleaned, plenium adjusted, airfilter and fuel filter would be a good start.

Garry

Hi Nigel
Have you checked your valve lift (rocker covers of etc)? My old 3.5 had lost several cam lobes by 275K's. New cam and lifters made big difference to power and economy.

Andy

Even when only 135k, my 95 Classic 3.9 gave around 18 litres per hundred.
- The figure above for city driving is the same as mine, 17 to 19 average.

Expect 19 to 22 if you try to keep up or match 'every other car' at the lights.

Can't say about off-road (don't trust it!) country or Freeway running, would depend on terrain.

Go for new plugs, rotor button, cap if a bit sus, advance timing as suggested, and new (BOSCH, Magnacor or Genuine) IGN leads.

If you're used to Jap petrols, yes, the LR v8 is 'not' as fuel- efficient. Live with it...

Will try the 10 degree setting on the dizzy and check that the vac advance is working . The only thing to replace will be the fuel filter. Thanks for your input and suggestions. Nigel

Will work thru several ideas. Thanks Nigel

Use NGK Iridium plugs with Magnecore leads, for the best spark possible.

Mine has done 260 000km and I think one injector is getting a bit tired, so I bought 8 yellow ones from the US but haven't tried them yet,

Cheers Charlie

... and don't forget to let us know what you've done...and resulting fuel useage.

- Brand of fuel can make a differance especially if you have 'iffy' suppliers over there, and there's some doubt as to whether 10% ethanol blends are better/worse.

- Naturally you've got enough air in the tyres & properly aligned.

My last 4 fill-ups average 17.1 litres/100km, or 16.5 mpg in old money. - About $25 per hundred at $1.46 / litre for 91 ULP