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[Nick W]

can you manage to remove the offending lead or for that matter all the leads with plenum still on. i did it a few weeks back but with it removed. cant recall if you can.lets say you can. and you have access to a meter it might be worth checking the leads first. water and heat does seem to kill them.

It's fiddly, but possible to replace the leads with the plenum in place. With that in mind, a quick visual inspection of them should be enough to condemn them, or not. A new set isn't expensive, and the faffing about doesn't really justify checking them with a meter. After all, you won't need to change them again.

[Andy H]

can you manage to remove the offending lead or for that matter all the leads with plenum still on. i did it a few weeks back but with it removed. cant recall if you can.lets say you can. and you have access to a meter it might be worth checking the leads first. water and heat does seem to kill them.

It's fiddly, but possible to replace the leads with the plenum in place. With that in mind, a quick visual inspection of them should be enough to condemn them, or not. A new set isn't expensive, and the faffing about doesn't really justify checking them with a meter. After all, you won't need to change them again.

When I changed the leads on my 1994 V6 about 15 years ago the leads from Vauxhall cost £75 per side. I thought that was expensive.......

[cam.in.head]

Yes new is always better .i just thought he may want to test leads then at least he would hopefully have found a fault if 1 or more were showing open circuit.

[Nick W]

It's fiddly, but possible to replace the leads with the plenum in place. With that in mind, a quick visual inspection of them should be enough to condemn them, or not. A new set isn't expensive, and the faffing about doesn't really justify checking them with a meter. After all, you won't need to change them again.

When I changed the leads on my 1994 V6 about 15 years ago the leads from Vauxhall cost £75 per side. I thought that was expensive.......

I paid about £30 over the counter at a local motor factor, just before they closed for the day. They're a standard service part for any dispack equipped Vauxhall V6, so I don't see any reason to buy them from a dealer.

[Diamond Black Geezer]

Mine are Bosch Vectra (B) V6, different part numbers to Omega, but they do fit/reach, if you see a cheap set for Veccy.

Definitely worth changing the HTs when you do the DIS pack 

[cam.in.head]

Not sure about not needing to touch them again thou.depends how long your keeping the car. My brothers 2.5 was bought in 2005 and didn't have its original leads on then. We replaced them approx 2009 with new Bosch.they failed this year due to heat with a bad misfire.5 of the 6 leads were open circuit .all the failures were where the lead crimps into the plug end due to heat . Also comparing to an original lead found in the boot the Bosch leads didn't fit as well as the original.could have been wrong type but the newer Bosch leads bought also didn't fit perfect although still worked perfect. They were taller ,and slightly thinner. Surprisingly number 6 was the OK lead

[terry paget]

I once bought a set of V6 plugs from a factor, nicely boxed up, for about £12. Put it on the car, ran fine, no misfires, but some radio unterference. I replaced them with an old set from my parts heap, interference cured.they were fine. Clearly Omega leads need to be resistive.

[Greenbay packer]

Yes new is always better .i just thought he may want to test leads then at least he would hopefully have found a fault if 1 or more were showing open circuit.

Starting to hope (or kid myself) that it may just be a lead that's at fault. Using an inline tester I have now confirmed that I have HT power getting to 5 out of 6 cylinders but nothing is getting to the front drivers side (no.1) spark plug. I'm sure I've read somewhere that the dis pack module has three sections inside, each of which covers 2 cylinders. Can anyone confirm this?  I was thinking (or hoping!) that if this is the case and the unit is faulty I would be most likely to lose two cylinders rather than just one.  Or can did pack failure just affect one pot?

[Kevin Wood]

The coil pack fires plug 1 and 4 from the same coil internally. It's not impossible for the output on no.1 to fail while no.4 is still fine (short to ground on the no.1 end of the coil would do it).

Also, an open circuit lead on no.1 would likely cause a weak or missing spark on no. 4.

Could try swapping the connectors at the coil pack for no. 1 and no. 4 and see if the spark moves to no. 1 and no. 4 is thereafter faulty?

[Greenbay packer]

The coil pack fires plug 1 and 4 from the same coil internally. It's not impossible for the output on no.1 to fail while no.4 is still fine (short to ground on the no.1 end of the coil would do it).

Also, an open circuit lead on no.1 would likely cause a weak or missing spark on no. 4.

Could try swapping the connectors at the coil pack for no. 1 and no. 4 and see if the spark moves to no. 1 and no. 4 is thereafter faulty?

Thanks for confirming that, it was what I was hoping to hear. Definitely going to concentrate on eliminating a lead issue now before looking at the dis pack.

[cam.in.head]

Gottabe worth a try especially if car was running well before the water issue and you have found a missing spark at 1 plug.

[Greenbay packer]

Gottabe worth a try especially if car was running well before the water issue and you have found a missing spark at 1 plug.

Definitely, thanks.

[Greenbay packer]

Just to complete the tale, I tried a new lead on no.1 but still got no spark despite no. 4 seeming to be ok (perhaps my tester was a bit misleading but the flash looked as good here as on the others that were working), so concluded the fault must be with the dis pack.  Decided to remove the unit the hard way so whipped out the wiper motor and undid the four bolts - it was fiddly, but I have a pretty useful 1/4' drive socket set with various extensions so was able to get it out fairly easily.  Couldn't see any sign of a fault or shorting on the outside of the unit, in fact it appeared to be in such good condition I began to doubt my diagnosis so I connected the leads up again with the unit lose on top of the plenum and tried the car again with new and old HT leads.  Same result, it still seemed to be firing on 5 cylinders.

Bought a new Bosch unit from autovaux on eBay for £70, tried it on top of the engine again and started the car.  Success!, running on six again and sounding nice and smooth.  Fitted the unit back on its shelf, which was more of a pain than getting it out, started the car again and all was still fine.  Tried the car on a short run, then took it away for the weekend and 450 miles later I'm still happy.

Thanks for all of your replies they were a big help, this forum is great.

[BazaJT]

Good to hear you've got a result