V8 Discovery

Um...sounds a bit like the old "dodgy spider" syndrome (crap soldering in the the PCB). When it does die, will it not restart for a period - if so, you can jury rig the coil to the battery to bypass the immobiliser - if it starts - that's the problem. ISTR that Rogers of Bedford have a nice fix for this - that doesn;t involve buying the new stupid LR fob replacement at £300..!

Neil, I did wonder about the 'dodgy spider thingy' but then I thought why would it keep going if I managed to keep the revs up? BTW it does the same on LPG and petrol so I'm assuming its more of an electrical problem rather than fuel. Richard

Richard,

Mine was intermittant - the local LR garage blamed all sorts of electrical things....but it was the spider - it;s the heart of thebeast ;-) Only has to rattle a bit. Even the AA diagnosed a faulty inlet manifold gasket?!?!?!?!

I'd take a look at the air flow meter, between the air intake and the engine. This isn't because I know one end of a V8 from the other, but rather that I had a similar problem on my 4.6 and that's what it was. If you can find a friend to swap with, you'll soon find out.

Of course, now somebody's going to point out that the 3.9 doesn't *have* an air flow meter and I'll look a complete berk.

David

DF> Of course, now somebody's going to point out that the 3.9 doesn't DF> *have* an air flow meter and I'll look a complete berk.

It does have one ;-) And I rather luckily have a working spare here ... so Richard .. where are you based?

I am in Maidstone, Kent. Whereabouts are you ? Richard

Richard,

I'm in Northampton......

Richard,

I have a spare MAF, TPS and Stepper....what shows you going to?

If it does it on LPG as well then you can more or less rule out the complete EFi system including the air flow meter and ECU.

Normally the only common components are the throttle position sensor ( throttle pot) and (possibly) the idle air control stepper motor. The TPS could cause your problem if it was giving out erroneous readings in the lower area - possibly causing the engine to over or under fuel and make it difficult to start but I'd expect the ECU to work around that.

The ignition system would be my main suspect as it is independant of both fuel systems and is capable of causing the problems you describe. A good starting point would be plugs and leads. Plugs take a hammering on LPG and it's a good idea to replace them every 12000 miles (I know some people replace them every 6000). HT leads need to be in good condition, especially for LPG. After that you are looking at possible distributor cap/rotor arm problems, a faulty ignition amplifier or a worn distributor. It's unlikely to be the coil if it runs OK at higher revs.

It is possible that the infamous spider could be the cause but IME this tends to stop the engine dead at any speed rather than be rpm specific. Easiest way to rule that out is to supply the ignition with it's own feed.

HTH

cheers

Dave W.

Mine had exactly the same problem on both LPG and Unleaded, and that was the air flow meter.

If you need more info from Rogers, drop me a line on here.

I work for them, on the transport side, but we are all based in the same place and I get staff discount. :-)

Neil, Pretty please I could do with borrowing these, I have a Disco V8 efi that is dead in Normandy, and I'm going out this weekend to try to get it going. I'm in Bedford.

Neil, We are going to the LRE show at Billing for three nights. Richard

I would check

i) vacuum - particularly the little vac pipe that runs from the plenum to the distributor (mine split causing similar symptoms)

ii) ignition amplifier (mine packed up, causing similar symptoms)

iii) air flow meter (mine was found to be fine when I had similar symptoms)

As you may have guessed, I had a very similar issue and found i) and ii) to both be at fault. Luckily both are cheap to fix.

Not nececelery. Mine had an intermittent fault, so it would check out fine most of the time. Only sussed it when it *happened* to play up just as I pulled out of the workshop at James French. 5 minutes earlier it'd been working flawlessly.

Which is why I thought swapping with a mate'd be a good idea - if his started playing up and Richard's didn't, it would be a bit of a clue.

David

Its definately an intermittant fault. It happened last summer and had been fine until yesterday. Drove into town and it would stop everytime for about

Hello, Colonel!

EEEEK! *NOW* I find out ;-)

Oh well....you will no doubt have seen Piglet there on a few occassions?! Sticker covered 4 tailpiped V8 Disco caged thingy!

P19 MUD ;-)

Hello, Colonel!

Mail me on snipped-for-privacy@www.mud-club.com (remove gnu to get me!) and I'll sort out something - all 3 are available to borrow ;-)

Get them back for the LRE show