4.6 misfire help wanted £££

mtkmarc · Nov 20, 2013

hi guys, just picked up a p38 4.6 with petrol and LPG,
ran fine first two days on petrol no problems, filled it up on lpg and ran fine for a day no problems. it has now started to misfire on one cylinder,

i dont want to throw money at it replacing the plugs leeds coil maf sensor etc if its something like a bad valve, would anyone in nottingham be willing to come check it out for a fee and if interested complete the work?
im no mechanic and range the local specialist LR servicing who cant get me in until 2 weeks,

want an honest experienced rangey enthusiast, to come check it out,
based near the centre of nottingham and can even travel as its drivable,

dont mind paying for your time/work just need it fixed asap

it misfires on idle, and through the revs, struggles for power, ocasionally pops, no water being used no smoke or rattles,
misfires on lpg and petrol

Datatek · Nov 21, 2013

Fire it up in the dark, lift the bonnet and look for electrical arcing around the plug leads, colis etc.

mtkmarc · Nov 23, 2013

update: ive replaced the leads, still no fix
it ran absoloutely fine today for 45 minutes then the dreaded misfire came back, it must be something electrical then?
i unplugged the MAF and it slowly died, then when i plugged it back in there was no change,

wil2813 · Nov 24, 2013

thor or gems ? single or multipoint ?

gfromleeds · Nov 24, 2013

The pop your getting is unburnt fuel hiting the hot cat and lighting in the exhaust so its not a valve
I had a very similar problem when I had my 4.6 turned out to be the coil pack had a bad link in it.
Oh and if you keep driving it you could do searious damage to the catalyst convertor cos the unburnt fuel overheats the cat then it starts to melt the honey comb blocking the flow of gasses

mtkmarc · Nov 24, 2013

It's a gems with multi point Just picked up a coil pack so I'll try tht today and let you know

grnoval · Nov 24, 2013

If its any help, i've just done the coil packs, on my 4.6 motronic - started with a misfire on 5, then 5 & 8. Lacking power and generally thinking petty can was the way forward.

New coilpacks on, and it goes like stink!

Parisien · Nov 24, 2013

Result Grnoval......fingers Xed, thats it fixed!

P

mtkmarc · Nov 24, 2013

replaced the coil pack and it seems fine now, popped and banged at first but soon cleared after a rev or two. im guessing that plug may have been fouled but is now clean?

it wont run on lgp now but i think that might just need resetting
fingers crossed its cured.

Druim · Nov 24, 2013

mtkmarc said:
replaced the coil pack and it seems fine now, popped and banged at first but soon cleared after a rev or two. im guessing that plug may have been fouled but is now clean?

it wont run on lgp now but i think that might just need resetting
fingers crossed its cured.

Where did you get a coil pack on a Sunday?

mtkmarc · Nov 24, 2013

:bolt: It was a second hand one, however if it hold up until payday on friday i will be purchasing a new one just for peace of mind, (left 2 of the awkward bolts out anyway to make it easier)

Saint.V8 · Nov 24, 2013

do the bolts act as part of the coil pack earth path???

EDIT: I think that maybe done through the wiring loom shield as per RAVE

wil2813 · Nov 25, 2013

mtkmarc said:
:bolt: It was a second hand one, however if it hold up until payday on friday i will be purchasing a new one just for peace of mind, (left 2 of the awkward bolts out anyway to make it easier)

save your money if it aint broke leave it alone

mtkmarc · Nov 25, 2013

Well it seems to have cure it, another journey completed without a hick, and it ran on lpg too.

4.6 misfire help wanted £££

mtkmarc

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Datatek

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mtkmarc

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wil2813

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gfromleeds

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mtkmarc

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grnoval

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Parisien

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Saint.V8

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wil2813

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