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View Full Version : Missfiring 3.9 V8-Please help


s111Truck_cab
5th Feb 2007, 18:47
Hi, my 94 3.9ES Disco(sequential LPG fitted) started missfiring a few days ago. The last time it did this was 5 months ago and new magnecor leads sorted it plus it had new head gaskets fitted with no water loss now. I took it to my Landy specialist and they were unsure of the prob but suggested trying some new leads of which i have just done with no difference. It misses throughout the rev range plus stutters when reved up and is even worse on lpg-just had the system fully tuned. So far it has had brand new genuine rotor arm, dizzy cap and leads. It had new plugs 3000 miles ago. The only things left are to try new plugs and a coil. What could it be if not any of the above, im told its not pressurising the cooling system and no liners are slipped???

s111Truck_cab
6th Feb 2007, 18:31
Well have tried new plugs and coil today with no difference. have been Speaking to my landy specialist again today and the only other thing he thinks it is that the head gaskets have gone again. Have been quoted some £800 to have them done including regrinding the valves. He said that when it was last done the strech bolts should have been replaced which on phoning my local garage who did them say they wern't replaced as they don't need to be? Who is right? my specialist has been working with v8's for 30 years. So I have booked my disco in to my local garage and have asked them to fix the problem as they did the job!

s111Truck_cab
6th Feb 2007, 20:53
bump

s111Truck_cab
8th Feb 2007, 19:08
Anyone got any ideas?

V8_Disco
8th Feb 2007, 21:42
It looks like i will have to rebuild the V8 myslef as places round here wont work on Gas ...

I have a post about this in the RR section as there are more V8s on there!

But HG is a consideration, as is the reuse of the bolts, this could be causing the loss of compreshion ... this is all conjecture mind

you might not be loosing coolant but does the system presurerise?

get it running well on petrol well first, gas comes second to that i have always been told that

Aidan