Got another one I need help with...

[Disco1fun]

hi Guys,

As some of you know I finally purchased a disco 6/8 weeks ago. I have been fixing all the issues that come with buying a $1000 disco but have hit my second issue that I havent been able to resolve with the search function on the forum.

She is a 98 3.9l dual fuel. Gas was fitted at the beginning of this year.

Sometimes (seems to be worse with aircon on) it surges underload. A bit like when your plugs/leads are starting to fail. Taking off from a stand still or powering up a hill she chugs and splatters but only on petrol.

Funny thing is that my father owns a 93 model 3.5l that had the same problem. Now whilst it was/is my fathers car I spent more time driving it than him as it was his second car and I used it to tow the boat. The problem dissapeared the day I was filling up the boat with premium and decided rather than switch pumps I would put premium in the old disco as well. Ran like a beauty and still does.....after a quick look turns out thats what we should have been putting in all along. As such I am running premium in the new one but the problem still exists.

Any ideas??

Oh and by the way......LOVE the truck...nothing better than pulling my mates squillion dollar patrols and prados out of the proverbial after they gave me such a hard time over wanting to buy a landrover. Total "build/repair cost" should be about $9k.....about $500 less than the prado's last engine rebuild @ 140k's. :-/

Cheers

[loanrangie]

The disco 3.5/3.9 are low compression so premium fuel is a bit of a waste really so i doubt very much its fuel related and probably more likely fuel pump/filter/ regulator or other electrical issue like MAF.
A bit vague i know but there are many variables, cheapest would be to check leads and do the ignition module upgrade found on this site.

[Disco1fun]

Thanks loanrangie. I should have said i am running 95 octane petrol not the 91.....apparently the "repair manual" says you should?? I will order the plugs and leads today and take a closer look at the ignition module upgrade.

With the 3.5l we replaced the plugs, leads, fuel pump, fuel filter which did nothing to fix the problem but haven't had an issue since changing to 95 octane 3 years ago.

I was thinking that being there has only been 2 disco's in the family both having the same problem that it would be pretty common.

Thanks again.

[robert.bisset]

I had this problem with my dual fuel disco and it turned out to be the MAF. The car ran the same with the MAF unplugged as it did plugged in which was as you've described. New Maf from europarts off ebay for $90 + $30 postage from the UK and now runs just as good if not better on fuel than on gas. Some people have apparently had problems with aftermarket MAF sensors but i've had mine in for over a month with no problems and i didn't want to pay $370+ for a reconditioned one.

[Gary S11]

Another thing you could try is , keep it on the premium fuel and crank your timing to 10 deg BTDC made a big difference to mine..Gary

[Disco1fun]

Thank you for the replies, Robert.Bisset you were spot on about the MAF...looks like it is cactus. Will order one shortly with the steering components i now need to order.....funny thing is i contacted the gas installer about what plugs and leads i should fit and mentioned the problems to him.....all i heard from there on was tune....cha ching complex..cha ching...will take a while to get it right for your vehicle....cha ching. lol.

Garys11, will play with timing as well, timing can make a massive difference.

Spent the weekend up at Jimna (cruiser park). The old girl performed really well. Unfortunately there was a tree across the road for the trip home that i launched off at 80kmh. Luckily it looks like ive only bent steering components and trashed the damper. Ive travelled that road a 100 times in my falcon's, luckily it was in the rover..would have written the falcon off. Our 11 month old didn't even wake.

Cheers

[bee utey]

Another thing worth doing is to have the engine idling on gas, open the bonnet and check the voltage at the brown/orange stripe wire at the MAF. It should be the same as battery voltage. If your gas installer is like many, he will have cut the injector positive wires and forgotten to check the MAF is still powered. Then the engine runs in limp mode unless started strictly on petrol. All you need is to cut the original wire to the MAF and run a new one from the live side of the LPG injector cut relay.