V8 DISCO INTERMITANT LOSS OF POWER

Joined: 06 Mar 2007 Location: gippsland Vic

I have a 95 Disco 3.9 duel fuel. Every now and then I get power loss the more I accelerate the more it losses power. Under 2000 revs its ok. Iddles fine, this is on both fuels. Have put new plugs, leads and vacumn advance unit. Any ideas, Please help as I am going to Cliff hanger in July. Thanks Claude.

Joined: 30 Oct 2004 Location: Sydney

With both fuels its not fuel.
Unless its a bad rotor/diuzzy cap/ leads/coil
Most likely after that is sticking exhaust valves.
regards Philip A

Joined: 13 Dec 2004 Location: Sunny Coast, Queensland

claude maniago wrote:

I have a 95 Disco 3.9 duel fuel. Every now and then I get power loss the more I accelerate the more it losses power. Under 2000 revs its ok. Iddles fine, this is on both fuels. Have put new plugs, leads and vacumn advance unit. Any ideas, Please help as I am going to Cliff hanger in July. Thanks Claude.

Don't listen to Phil .. just keep driving it and sooner or later the power loss won't be intermittent anymore

.. it will become permanent Very Happy

Joined: 04 Aug 2007 Location: Brisvagas

Hi - I've got a 97 on straight unleaded that would rev hard to 5000 before farting and splurting down to the 2000 mark no matter how hard I jammed the pedal to the floor. It would continue to fart for a little while longer as i drove it nicely again. I did the same with the ignition components with no improvement. As it had a unichip though I got it dynoed and the tuner had to put more fuel in the map as it was starving itself... way too lean throughout the rev range. I also have a clean fuel filter and we ruled out the pump on the dyno... its helped but my fuel consumption still appears to be crap... $240 though

Joined: 05 May 2005 Location: North Yorkshire, UK

claude maniago wrote:

I have a 95 Disco 3.9 duel fuel. Every now and then I get power loss the more I accelerate the more it losses power. Under 2000 revs its ok. Iddles fine, this is on both fuels. Have put new plugs, leads and vacumn advance unit. Any ideas, Please help as I am going to Cliff hanger in July. Thanks Claude.

Assuming the LPG uses an ECU then it'd be worth checking the TPS for consistency through the range. Dirt, corrosion or wear on the TPS could fool the ECU into using the wrong fuelling and is normally used by both LPG and petrol ECUs on dual fuel vehicles.

Joined: 06 Mar 2007 Location: gippsland Vic

I had it dynoed and the fuel mix and timing needed minor adjustments and all electrical showed good. then on the way home did it again under load. Thanks Claude.

Posted: Thu Apr 24, 2008 8:49 pm

claude maniago wrote:

I had it dynoed and the fuel mix and timing needed minor adjustments and all electrical showed good. then on the way home did it again under load. Thanks Claude.

I recently had the same symptoms, tried all what you have done and still no good.
Turned out intermittent sticking of the exhaust valves . Also if the valve face is not seating in it's seat and not sealing , then exhaust gases leak past and result is loss of power is not sealing .
I found this under load trying to get up hills

Joined: 06 Mar 2007 Location: gippsland Vic

Rovernaut was heads off or what did you do?
Thanks Claude.

Posted: Sat Apr 26, 2008 12:45 pm

claude maniago wrote:

Rovernaut was heads off or what did you do?
Thanks Claude.

I took heads off , had the heads pressure tested, heads rebuilt, faced etc. new stem seals
New head gaskets, head bolts, cost me all up about $1100 with me pulling the heads off and the reinstallation.
Instant power gains, drivers like new now.
Karcraft in Sydney, do mail order, good source for Rover parts, got all my gaskets there, they have many genuine parts/ or OEM manufacturers parts. Got my stuff there very happy and quality very good

Joined: 06 Mar 2007 Location: gippsland Vic

Thanks to everyone. Sticky exhaust valve seem to be the problem. Nulax free lifter did the job.
Regards Claude, go the Disco! Twisted Evil

Joined: 20 Aug 2007 Location: mornington peninsula

might be a stupid question but what unleaded fuel do you stick in it?

Joined: 19 Apr 2004 Location: the sticks - Tas

had same issue when Disco was first bought - new dissy cap and leads, fuel pump and dissy module plus oil change (was like glue) and Italian tune up fixed it. Now valve bounces freely!!

Stuff knows how the previous owner towed a 2 tonne trailer and boat with it! Amazing how these vehicles get abused and still keep going.

Joined: 06 Mar 2007 Location: gippsland Vic

Shell unleaded but I also put injector cleaner in it. Theses things are great Istill don't think you could stop. Go DISCO! Laughing

Joined: 20 Aug 2007 Location: mornington peninsula

i run a 98 octaine premium unleaded fuel in mine i get lot better mileage a lot cleaner burn and the aditives in it help with lubrication and keep pre ignition to a minimin even though its tuned for gas only just food for thought

Joined: 31 May 2006 Location: Bellarine, Brackistan

Couple of weeks ago I took a 17 foot tinny with an old 60 hp Johnson up the Glenelg River from Nelson in far west Vic.

Wasn't sure what the fuel use was going to be.

The first tank was 12 month old ordinary unleaded and we got 39 km out of it. The next tank was new premium unleaded and we got 70 km out of that.

Sure surprised me what the difference was.

DL