Missfire? Coil Pack replacment Help Required

[briansmith246]

Hi all,

After some deliberation i ended up buying another V8 Discovery (series 2 4.0 V8 ES Manual complete with ACE, air and twin electric showers er sorry 'sunroofs')

Advice required in a different area..

I drove the car back from purchasing (300 miles and it never missed a beat) however recently it has started playing up.. i am not getting a traditional misfire, but more of a hessitation and rough running under load, i can rev through it and the car accelerates away (no smoke etc) however it is still not as smooth as it should be, it idles well but with a very slight fluctuation. Car has done 80k.

I have rave cd and seek advice with the following jobs;

Replacing both coil packs, ht leads and plugs
Replacing both rocker cover gaskets (slight weep from both)
Throttle body preheater modification part (slight coolant weep)
Oil and air filter change + oil (what do you recomend for this engine?)

My local Land Rover supplier (Brookwells - Devon) informed me that they had only ever sold two upper plenum chamber gaskets for this motor, so can i get away without expending another £30 of hard earned cash!

I intend to photograph all the steps and then post on here to help out people in the future - I have just done 'replacing gearbox bias plate' and will be posting that soon.

Help and advice greatly apreciated, and any 'experts' in the Torbay area welcome to pop round to help or hold the camera ! ..... :)

[V8_Disco]

Sounds rude but its been covered before do a search it will turn up

I would look at getting the Rave CD for the car, its the workshop manual and has all the info and blown up diagrams, its a fidaly job but well doable

if you are thinikning of running on LPG use genuine componesnts, In fact its such a pain in the *** I would only use these or OEM as its not a job you want to do again in the near futre

Tip, use Maignour (sp?) leeds they do make a diffenece and are cheeper than the lower spec LR ones

Aidan

[JulesV8]

"sp": Magnecor leads.

I agree with V8 Disco, they are very good though you could also look at Lumenition ones.

Essentially, go for 8mm or 10mm to make sure there is a good spark at the plugs.

[briansmith246]

Sounds rude but its been covered before do a search it will turn up



I would look at getting the Rave CD for the car, its the workshop manual and has all the info and blown up diagrams, its a fidaly job but well doable

if you are thinikning of running on LPG use genuine componesnts, In fact its such a pain in the *** I would only use these or OEM as its not a job you want to do again in the near futre

Tip, use Maignour (sp?) leeds they do make a diffenece and are cheeper than the lower spec LR ones


Aidan


Thanks Aidan,

No its not being rude, although i did search through Discovery forum before posting (should have looked in RR section as well?), perhaps i should have said, is there anything else i should be looking at with these symptoms, all the pointers are ignition and the leads do look a little dated, my intention is to replace everything whilst its all off incl coil packs as i dont want to mess about with it again.

I know to use quality components

I have Rave CD and was just after advice on actually removing the bits, pitfalls hidden dowels/bolts etc, and anything else to look for whilst im lurking under bonnet. Also no mention about upper plenum gasket rave cd says replace, shop says no need as they never sell them?

For some of us 'amateur mechanics' it is sometimes nessecary to ask what are dumb questions to the more enlightened, before dismantling large lumps of machinery.

Will be posting step by step photos for the less experienced after i've 'completed the task' as they are extremley useful (downloaded the step by step guide to removing headlining / sunroofs to fix my twin showers) and i will be posting Bias Plate replacment this weekend now i have fixed my wobbly gear lever...

Many thanks for advice thus far...

[briansmith246]

Sorry i forgot,

No LPG (complicated enough!) and engine managment light has not illuminated. (missfire more of hessitation until revved through)

Thanks
Brian

[v8jobster]

have you had the plugs out yet??

That would be my 1st point of call, and change them as precautionary to see if the problem still persists.

[briansmith246]

have you had the plugs out yet??

That would be my 1st point of call, and change them as precautionary to see if the problem still persists.

Just gathering the parts together, hoping to tackle this weekend British Summer allowing... Will post outcome

[V8_Disco]

Thanks Aidan,

No its not being rude, although i did search through Discovery forum before posting (should have looked in RR section as well?), perhaps i should have said, is there anything else i should be looking at with these symptoms, all the pointers are ignition and the leads do look a little dated, my intention is to replace everything whilst its all off incl coil packs as i dont want to mess about with it again.

I know to use quality components

I have Rave CD and was just after advice on actually removing the bits, pitfalls hidden dowels/bolts etc, and anything else to look for whilst im lurking under bonnet. Also no mention about upper plenum gasket rave cd says replace, shop says no need as they never sell them?

For some of us 'amateur mechanics' it is sometimes nessecary to ask what are dumb questions to the more enlightened, before dismantling large lumps of machinery.

Will be posting step by step photos for the less experienced after i've 'completed the task' as they are extremley useful (downloaded the step by step guide to removing headlining / sunroofs to fix my twin showers) and i will be posting Bias Plate replacment this weekend now i have fixed my wobbly gear lever...

Many thanks for advice thus far...

They might be in th RR section as I tend to use both ...

Coil packs - Very tight Fit!, and bolted to both the upper and lower inlet manafold, I dont bolt the top to the upper inlet manafold as locating this with the LPG kit as well is a right pain, done 30k since I started doing this not an issue makes refiting easyser and you can get a bit more acess later if needed,

Getting the clips and electical socket of the coil packs is also a pain make sure you have a good grip on the sprung wire as you dont want this shoting around the workspace

Its not "hard" just a job that takes alot longer than it should

hope this is of some help

Aidan

[briansmith246]

Job done,

Removed plenum chamber etc, replaced leads with Magnecor as suggested, new plugs and air filter fitted, starts and runs superb. Left original coil packs as they looked fine.

The job was a b*****d to do requiring me to actually climb on top of engine to see where, and access, the coil pack bolts !!

I took photos along the way and will post along with bias plate repair once i have finished replacing the bonnet release cable (as soon as i finished the ignition problem the bonnet wouldnt open !!! - why did i buy another bloody Land Rover ????!!!)

Thanks for all the advice

[V8_Disco]

Good to here you got it done, and yes acess to the coil packs was designed for a monkey!

Did you have issues with the top or the bottom bolts, I once droped a lower bolt onto the Gasget above the V God I was pleased I had a magnetic stick that day!

A